[0001] This invention relates to an improved processing method for developing originating
silver halide photographic elements.
[0002] The basic image-forming process of color photography comprises exposing a silver
halide photographic recording material to light, and chemically processing the material
to reveal a usable image. The fundamental steps of this processing typically entail:
(1) treating the exposed silver halide with a color developer wherein some or all
of the silver halide is reduced to metallic silver while an organic dye is formed
from the oxidized color developer; and (2) removing the silver metal thus formed and
any residual silver halide by the desilvering steps of bleaching, wherein the developed
silver is oxidized to silver salts, and fixing, wherein the silver salts are dissolved
and removed from the photographic material. The bleaching and fixing steps may be
performed sequentially or as a single step, that is discussed herein as blixing. In
some methods of color image formation, additional color or black & white development
steps, chemical fogging steps and ancillary stopping, washing, accelerating and stabilizing
steps may be employed.
[0003] In many situations, the usable image is provided to a customer by a multi-stage method
that involves exposing a light sensitive originating element to a scene, and developing
and desilvering that originating element to form a color image. The originating element
may, for example, be a color negative film or a motion picture negative film.
[0004] The resultant color image is then used to modulate the exposure of a light sensitive
display element, with optional enlargement, in a printer. The display element may,
for example, be a color paper, an intermediate film, or a motion picture projection
film. The exposed display element is then developed and desilvered to form a useful
color image that duplicates the original scene.
[0005] Originating elements are typically designed to allow good exposure with available
light under a wide variety of lighting conditions, that is, good sensitivity (speed/grain)
and dynamic range (long latitude and low gamma) are desired. Conversely, display elements
are typically designed so as to allow a full range of density formation after well
defined exposure and process conditions in a printer, that is, good image discrimination
(high density and low fog), low dynamic range (short latitude and high gamma) and
easy and consistent processing are desired. These greatly different needs are typically
met by providing originating and display elements that differ markedly in silver halide
content and composition as well as in the layer orders and types and quantities of
image forming chemicals employed in each. One major difference in composition is evidenced
in the use of silver iodobromide emulsions in the originating element, a color negative
film for example, for their high sensitivity and desirable image structure properties
and the use of silver chloride or silver chlorobromide emulsions in the display element,
a color paper for example, for their low sensitivity, short latitude and good developability,
as well as their ease of reproducible desilvering.
[0006] Attempts to provide camera speed color originating films that may be rapidly processed
have, to date, met with only limited success. EP-A-0 468 780 describes low bromide
ion developer formulations said to be useful with color negative films employing cubic
silver bromochloride emulsions. Although rapid development using a low bromide developer
is described, the overall light sensitivity of these films is deficient. DE 4,227,075
teaches that the quantity of bromide in these emulsions leads to rapid deactivation
of the developer solution as bromide ion washes out of the film and into the developer
solution during a development step.
[0007] Cubic shaped silver chloride emulsions and useful development methods are described
in EP-A-0 466 417, and in Japanese Kokai 04-101135. Here again, rapid access is apparently
obtained in a low bromide color developer solution but only with relatively light
insensitive emulsions not fully suitable for use in a hand-held camera. Other low
bromide developer solutions suitable for color papers employing low sensitivity regular
shaped high chloride emulsions are disclosed in US-A-5,004,675; US-A-5,066,571; US-A-5,070,003;
US-A-5,093,226; US-A-5,093,227; US-A-5,108,877; US-A-5,110,713; US-A-5,110,714; US-A-5,118,592;
US-A-5,153,108; and US-A-5,162,195. These publications teach that low quantities of
bromide ion in the developer improve staining and pressure fog characteristics. Concentrations
of bromide ion between about 0.05 mmolar and 1 mmolar are described as optimal while
bromide ion concentrations greater than about 1 mmolar are discouraged since these
are said to reduce sensitivity of the regular shaped emulsions.
[0008] Further, it is generally known that higher quantities of bromide ion in a developer
intended for low to no bromide ion containing high chloride regular shaped emulsions
lead to incorporation of bromide ion from the developer into undeveloped portions
of the emulsion during a development step. This incorporation, know colloquially as
metathesis, results in two related problems, viz. the depletion of bromide from the
developer that must then be replenished more often than typically desired, and incorporation
of the bromide into the emulsion which must then be removed during a desilvering step.
Silver bromide is well known to be more difficult to remove than is silver chloride.
[0009] The following publications discuss the use of developer solutions containing little
to no bromide ion with high chloride emulsions. US-A-4,952,490 describes a color negative
film employing large, optimally sensitized regular shaped silver chloride emulsions
featuring 〈111〉 crystallographic faces. Organic grain surface stabilizers and sensitizing
dyes are added at precipitation to stabilize the grain surface and shape. While somewhat
improved sensitivity is obtained, high sensitivity and adequate image characteristics
are not simultaneously available with these emulsions since the large, regularly shaped
grains provide only limited useful sensitivity. This is due to the roll-off in the
sensitivity of large symmetric emulsions as a result of decreased intralayer light
scatter, decreased dye-density-yield on color development and decreased quantum sensitivity
with increased grain surface area. Low aspect ratio, tabular shaped and surface stabilized
silver chloride emulsions, again with intrinsically unstable 〈111〉 crystallographic
faces, are likewise described in US-A-4,952,491. while the use of tabular shaped emulsion
grains provides some improvement in useful sensitivity, the tabular grains are apparently
quite susceptible to pressure induced marks thus limiting their use for faithfully
recording images. Additionally, the organic surface stabilizers described in both
of these related publications are known to additionally stabilize the exposed and
developed emulsions against desilvering, thus leading to poor quality images.
[0010] Cubic shaped silver chloride emulsion grains specifically precipitated with organic
grain growth directors and described as corner development grains (CDGs) are disclosed
at US-A-4,820,624 and US-A-4,865,962. When properly sensitized these symmetric CDG
emulsions are said to provide improved sensitivity so that they may be useful in both
color papers and rapid access camera speed films. Again, the developer solution employed
to provide a rapid access camera speed film contains no bromide ion.
[0011] US-A-5,344,750 describes the use of highly light sensitive silver iodobromide emulsions
in a camera speed film that is then processed at elevated temperatures in developer
solutions containing highly concentrated developing agent and bromide ion. The higher
temperatures and otherwise tightly controlled developer solution composition required
by this approach are difficult to provide especially since continuous processing leads
to a steady decrease in developing agent and developer bromide ion concentration that
results in unwanted degrees of fog growth. Further, the higher levels of iodide ion
in the emulsions remove the possibility of ready and rapid desilvering.
[0012] Yet another means of resolving these difficulties is proposed in DE 4,227,075 where
the bromide ion content of the light sensitive emulsions and the developer solution
are both said to be critical to the sensitivity issue and the developability issue.
This publication proposes that photographic materials employing cubic silver iodochloride
emulsions comprising only very limited quantities of bromide ion, when developed in
a very low to no bromide ion developer solution, can provide rapidly developable films
of somewhat improved sensitivity. The desilvering problems inherent in high iodide
emulsion elements are however still present.
[0013] Overall, the art uniformly recommends the use of low to no bromide ion developer
solutions. More recently, novel high chloride tabular grain emulsions with intrinsically
stable 〈100〉 crystallographic faces have been described in US-A-5,320,938; US-A-5,275,930;
US-A-5,264,337; and US-A-5,292,632 inter alia. US-A-5,310,635 and US-A-5,356,764 teach
that these emulsions show sufficiently high sensitivity to allow the fabrication of
camera speed three color films. Here, however, only relatively long development times
of 195 seconds are employed with the multicolor elements disclosed so that the full
advantage of a rapidly developable high sensitivity color film is not yet fully realized.
[0014] Attempts to rapidly develop multilayer, multicolor color films employing high chloride
tabular grain emulsions with 〈100〉 crystallographic faces with developers containing
no or limited quantities of bromide ion have resulted in an undesirable imbalance
in the developability of the various color layers. Further, development in these low
bromide ion developers results in inferior signal-to-noise characteristics and inferior
granularity in the formed image.
[0015] Thus a need still exists for a camera speed color element suitable for rapid access
color development.
[0016] This invention provides a rapid access image forming process for high sensitivity
color photographic elements comprising the step of contacting an imagewise exposed
camera speed color photographic element with a developing solution wherein:
(A) the color photographic element comprises a support and, coated on the support,
at least one radiation sensitive emulsion layer having in reactive association an
image dye forming coupler and within which at least 50 percent of total grain projected
area is accounted for by tabular grains each
(1) bounded by {100} major faces having adjacent edge ratios of less than 10;
(2) having an aspect ratio of at least 2; and
(3) comprising at least 50 mol % silver chloride;
(B) the contact time of the color photographic element with the developing solution
is between 5 and 150 seconds; and
(C) the developing solution has:
(1) a temperature of from 25 to 65 °C;
(2) bromide ion at a concentration from 0.25 to 50 mmol/liter;
(3) a color developing agent at a concentration from 1 to 200 mmol/liter;
(4) a ratio of developing agent concentration to bromide ion concentration of between
60:1 and 0.5:1; and
(5) a pH of from 9 to 12; and wherein
(D) the camera speed color photographic element exhibits a sensitivity of at least
ISO 25.
[0017] This invention provides for a highly light sensitive color film that can be employed
in a hand-held camera and is rapidly and evenly developable so as to provide a pleasingly
balanced image. Further, the developed color film exhibits improved granularity and
signal-to-noise characteristics that further contribute to the pleasing quality of
the formed image. Additionally, the film can be rapidly and completely desilvered
using a variety of environmentally preferred desilvering agents thereby enabling the
production of a colorful image in an ecologically friendly manner.
Figure 1 is a shadowed photomicrograph of carbon grain replicas of an emulsion of
the invention and
Figure 2 is a shadowed photomicrograph of carbon grain replicas of a control emulsion.
[0018] The originating silver halide photographic elements described herein allow good exposure
with available light under a wide variety of lighting conditions. They provide good
speed with low graininess. At a minimum these originating elements have an ISO speed
rating of 25 or greater, with greater than 50 being preferred.
[0019] The speed or sensitivity of color negative photographic materials is inversely related
to the exposure required to enable the attainment of a specified density above fog
after processing. Photographic speed for color negative films with a gamma of about
0.65 has been specifically defined by the American National Standards Institute (ANSI)
as ANSI Standard Number PH 2.27 - 1979 (ASA speed) and relates to the exposure levels
required to enable a density of 0.15 above fog in the green light sensitive and least
sensitive recording unit of a multicolor negative film. This definition conforms to
the International Standards Organization (ISO) film speed rating.
[0020] It is appreciated that according to the above definition, speed depends on film gamma.
Color negative films intended for other than direct optical printing may be formulated
or processed to achieve a gamma greater or less than 0.65. For the purposes of this
application, the speeds of such films are determined by first linearly amplifying
or deamplifying the achieved density vs log exposure relationship (that is the gamma)
to a value of 0.65 and then determining the speed according to the above definitions.
[0021] The photographic emulsions used in the originating element may include, among others,
silver chloride, silver bromochloride, silver bromide, silver iodobromochloride, silver
iodochloride or silver iodobromide. Silver chloride and silver bromochloride emulsions
are preferred. Whatever the emulsion mix, the originating photographic element must
contain at least 50 mol % silver chloride, with 70 mol % being preferred and over
98 mol % being most preferred. The total amount of silver iodide in the photographic
element must be less than 2 mol %, and preferably less than 1 mol %. The total amount
of coated silver may be from about 1 to 10 grams per square meter, with less than
7 grams per square meter preferred, and less than 4 grams per square meter being most
preferred.
[0022] The originating photographic elements of this invention contain at least one radiation
sensitive silver halide emulsion containing a dispersing agent and a high silver chloride
grain population. At least 50 percent of total grain projected area of the high silver
chloride grain population is accounted for by tabular grains that (1) are bounded
by {100} major faces having adjacent edge ratios of less than 10 and (2) each have
an aspect ratio of at least 2. The tabular grains are intrinsically stable and do
not require the use of stabilizers such as thiirane, thiepine, thiophene, thiazole
and other such cyclic sulfides; mercaptoacetic acids, cysteine, penicillamine and
other thiols; and acetylthiophenol and related thioesters and thiocarbanimides to
maintain their shape. Such stabilizers may restrain development.
[0023] It has further been discovered that the use of a certain class of development inhibitors
can inhibit the desilvering of the originating photographic elements used in this
invention. Development inhibitors typically comprise a silver halide binding group
having a sulfur, selenium, tellurium or heterocyclic nitrogen or carbon with a free
valence that can form a bond to silver atoms, as well as a ballast moiety. Originating
photographic elements that contain development inhibitor releasing (DIR) compounds
that enable release of development inhibitors having a sulfur with a free valence
that can form a bond to a silver atom appear to desilver more slowly than those containing
other classes of development inhibitors or no development inhibitor. Therefore, with
this invention it is preferred to use DIR compounds that enable release of development
inhibitors with a heterocyclic nitrogen as a silver binding group, such as oxazoles,
thiazoles, diazoles, triazoles, oxadiazoles, thiadiazoles, oxathiazoles, thiatriazoles,
benzotriazoles, tetrazoles, benzimidazoles, indazoles, isoindazoles, benzodiazoles
or benzisodiazoles. Development inhibitors having a sulfur with a free valence can,
however, have other advantages and may be utilized in limited quantities that do not
greatly effect desilvering.
[0024] The identification of emulsions satisfying the requirements of the invention and
the significance of the selection parameters can be better appreciated by considering
a typical emulsion. Figure 1 is a shadowed photomicrograph of carbon grain replicas
of a representative emulsion, described in detail in Example 1 below. It is immediately
apparent that most of the grains have orthogonal tetragonal (square or rectangular)
faces. The orthogonal tetragonal shape of the grain faces indicates that they are
{100} crystal faces.
[0025] The projected areas of the few grains in the sample that do not have square or rectangular
faces are noted for inclusion in the calculation of the total grain projected area,
but these grains clearly are not part of the tabular grain population having {100}
major faces.
[0026] A few grains may be observed that are acicular or rod-like grains (hereinafter referred
as rods). These grains are more than 10 times longer in one dimension than in any
other dimension and can be excluded from the desired tabular grain population based
on their high ratio of edge lengths. The projected area accounted for by the rods
is low, but, when rods are present, their projected area is noted for determining
total grain projected area.
[0027] The grains remaining all have square or rectangular major faces, indicative of {100}
crystal faces. To identify the tabular grains it is necessary to determine for each
grain its ratio of ECD to thickness (t)--that is, ECD/t. ECD is determined by measuring
the projected area (the product of edge lengths) of the upper surface of each grain.
From the grain projected area the ECD of the grain is calculated. Grain thickness
is commonly determined by oblique illumination of the grain population resulting in
the individual grains casting shadows.
[0028] From a knowledge of the angle of illumination (the shadow angle) it is possible to
calculate the thickness of a grain from a measurement of its shadow length. The grains
having square or rectangular faces and each having a ratio of ECD/t of at least 2
are tabular grains having {100} major faces. When the projected areas of the {100}
tabular grains account for at least 50 percent of total grain projected area, the
emulsion is a tabular grain emulsion.
[0029] In the emulsion of Figure 1, tabular grains account for more than 50 percent of total
grain projected area. From the definition of a tabular grain above, it is apparent
that the average aspect ratio of the tabular grains can only approach 2 a minimum
limit. In fact, tabular grain emulsions of the invention typically exhibit average
aspect ratios of 5 or more, with high average aspect ratios (>8) being preferred.
That is, preferred emulsions according to the invention are high aspect ratio tabular
grain emulsions. In specifically preferred emulsions according to the invention, average
aspect ratios of the tabular grain population are at least 12 and optimally at least
20. Typically the average aspect ratio of the tabular grain population ranges up to
50, but higher aspect ratios of 100, 200 or more can be realized. Emulsions within
the contemplation of the invention in which the average aspect ratio approaches the
minimum average aspect ratio limit of 2 still provide a surface to volume ratio that
is 200 percent that of cubic grains.
[0030] The tabular grain population can exhibit any grain thickness that is compatible with
the average aspect ratios noted above. However, particularly when the selected tabular
grain population exhibits a high average aspect ratio, it is preferred to additionally
limit the grains included in the selected tabular grain population to those that exhibit
a thickness of less than 0.3 mm and, optimally, less than 0.2 mm. It is appreciated
that the aspect ratio of a tabular grain can be limited either by limiting its equivalent
circular diameter or increasing its thickness. Thus, when the average aspect ratio
of the tabular grain population is in the range of from 2 to 8, the tabular grains
accounting for at least 50 percent of total grain projected area can also each exhibit
a grain thickness of less than 0.3 mm or less than 0.2 mm. Nevertheless, in the aspect
ratio range of from 2 to 8 particularly, there are specific photographic applications
that can benefit by greater tabular grain thicknesses. For example, in constructing
a blue recording emulsion layer of maximum achievable speed it is specifically contemplated
that tabular grain thicknesses that are on average 1 mm or even larger can be tolerated.
This is because the eye is least sensitive to the blue record and hence higher levels
of image granularity (noise) can be tolerated without objection. There is an additional
incentive for employing larger grains in the blue record in that it is sometimes difficult
to match in the blue record the highest speeds attainable in the green and red record.
A source of this difficulty resides in the blue photon deficiency of sunlight. While
sunlight on an energy basis exhibits equal parts of blue, green and red light, at
shorter wavelengths the photons have higher energy. Hence, on a photon distribution
basis, daylight is slightly blue deficient.
[0031] The tabular grain population preferably exhibits major face edge length ratios of
less than 5 and optimally less than 2. The nearer the major face edge length ratios
approach 1 (that is, equal edge lengths) the lower is the probability of a significant
rod population being present in the emulsion.
[0032] Further, it is believed that tabular grains with lower edge ratios are less susceptible
to pressure desensitization.
[0033] In one specifically preferred form of the invention, the tabular grain population
accounting for at least 50 percent of total grain projected area is provided by tabular
grains also exhibiting 0.2 mm. In other words, the emulsions are in this instance
thin tabular grain emulsions.
[0034] Surprisingly, ultrathin tabular grain emulsions have been prepared satisfying the
requirements of the invention. Ultrathin tabular grain emulsions are those in which
the selected tabular grain population is made up of tabular grains having an average
thickness of less than 0.06 mm. Prior to the present invention, the only ultrathin
tabular grain emulsions of a halide content exhibiting a cubic crystal lattice structure
known in the art contained tabular grains bounded by {111} major faces. In other words,
it was thought essential to form tabular grains by the mechanism of parallel twin
plane incorporation to achieve ultrathin dimensions. Emulsions according to the invention
can be prepared in which the tabular grain population has a mean thickness down to
0.02 mm and even 0.01 mm. Ultrathin tabular grains have extremely high surface to
volume ratios. This permits ultrathin grains to be photographically processed at accelerated
rates. Further, when spectrally sensitized, ultrathin tabular grains exhibit very
high ratios of speed in the spectral region of sensitization as compared to the spectral
region of native sensitivity: For example, ultrathin tabular grain emulsions according
to the invention can have entirely negligible levels of blue sensitivity, and are
therefore capable of providing a green or red record in a photographic product that
exhibits minimal blue contamination even when located to receive blue light.
[0035] The characteristic of tabular grain emulsions that sets them apart from other emulsions
is the ratio of grain ECD to thickness (t). This relationship has been expressed quantitatively
in terms of aspect ratio. Another quantification that is believed to assess more accurately
the importance of tabular grain thickness is tabularity:

where
T is tabularity;
AR is aspect ratio;
ECD is equivalent circular diameter in micrometers (mm); and
t is grain thickness in micrometers.
The high chloride tabular grain population accounting for 50 percent of total grain
projected area preferably exhibits a tabularity of greater than 25 and most preferably
greater than 100. Since the tabular grain population can be ultrathin, it is apparent
that extremely high tabularities, ranging to 1000 and above are within the contemplation
of the invention.
[0036] The tabular grain population can exhibit an average ECD of any photographically useful
magnitude. For photographic utility, average ECD's of less than 10 mm are contemplated,
although average ECD's in most photographic applications rarely exceed 6 mm. Within
ultrathin tabular grain emulsions satisfying the requirements of the invention it
is possible to provide intermediate aspect ratios with ECD's of the tabular grain
population of 0.10 mm and less. As is generally understood by those skilled in the
art, emulsions with selected tabular grain populations having higher ECD's are advantageous
for achieving relatively high levels of photographic sensitivity while selected tabular
grain populations with lower ECD's are advantageous in achieving low levels of granularity.
[0037] So long as the population of tabular grains satisfying the parameters noted above
accounts for at least 50 percent of total grain projected area, a photographically
desirable grain population is available. It is recognized that the advantageous properties
of the emulsions of the invention are increased as the proportion of tabular grains
having {100} major faces is increased. The preferred emulsions according to the invention
are those in which at least 70 percent and optimally at least 90 percent of total
grain projected area is accounted for by tabular grains having {100} major faces.
It is specifically contemplated to provide emulsions satisfying the grain descriptions
above in which the selection of the rank ordered tabular grains extends to sufficient
tabular grains to account for 70 percent or even 90 percent of total grain projected
area.
[0038] So long as tabular grains having the desired characteristics described above account
for the requisite proportion of the total grain projected area, the remainder of the
total grain projected area can be accounted for by any combination of coprecipitated
grains. It is, of course, common practice in the art to blend emulsions to achieve
specific photographic objectives. Blended emulsions in which at least one component
emulsion satisfies the tabular grain descriptions above are specifically contemplated.
[0039] If tabular grains failing to satisfy the tabular grain population requirements do
not account for 50 percent of the total grain projected area, the emulsion does not
satisfy the requirements of the invention and is, in general, a photographically inferior
emulsion. For most applications (particularly applications that require spectral sensitization,
require rapid processing and/or seek to minimize silver coverages) emulsions are photographically
inferior in which many or all of the tabular grains are relatively thick--for example,
emulsions containing high proportions of tabular grains with thicknesses in excess
of 0.3 mm.
[0040] More commonly, inferior emulsions failing to satisfy the requirements of the invention
have an excessive proportion of total grain projected area accounted for by cubes,
twinned nontabular grains, and rods. Such an emulsion is shown in Figure 2. Most of
the grain projected area is accounted for by cubic grains. Also the rod population
is much more pronounced than in Figure 1. A few tabular grains are present, but they
account for only a minor portion of total grain projected area.
[0041] The tabular grain emulsion of Figure 1 satisfying the requirements of the invention
and the predominantly cubic grain emulsion of Figure 2 were prepared under conditions
that were identical, except for iodide management during nucleation. The Figure 2
emulsion is a silver chloride emulsion while the emulsion of Figure 1 additionally
includes a small amount of silver iodide.
[0042] Obtaining emulsions satisfying the requirements of the invention has been achieved
by the discovery of a novel precipitation process. In this process grain nucleation
occurs in a high chloride environment in the presence of iodide ion under conditions
that favor the emergence of {100} crystal faces. As grain formation occurs the inclusion
of iodide into the cubic crystal lattice being formed by silver ions and the remaining
halide ions is disruptive because of the much larger diameter of iodide ion as compared
to chloride ion. The incorporated iodide ions introduce crystal irregularities that
in the course of further grain growth result in tabular grains rather than regular
(cubic) grains.
[0043] It is believed that at the outset of nucleation the incorporation of iodide ion into
the crystal structure results in cubic grain nuclei being formed having one or more
screw dislocations in one or more of the cubic crystal faces. The cubic crystal faces
that contain at least one screw dislocation thereafter accept silver halide at an
accelerated rate as compared to the regular cubic crystal faces (that is, those lacking
a screw dislocation). When only one of the cubic crystal faces contains a screw dislocation,
grain growth on only one face is accelerated, and the resulting grain structure on
continued growth is a rod. The same result occurs when only two opposite parallel
faces of the cubic crystal structure contain screw dislocations. However, when any
two contiguous cubic crystal faces contain a screw dislocation, continued growth accelerates
growth on both faces and produces a tabular grain structure. It is believed that the
tabular grains of the emulsions of this invention are produced by those grain nuclei
having two, three or four faces containing screw dislocations.
[0044] At the outset of precipitation a reaction vessel is provided containing a dispersing
medium and conventional silver and reference electrodes for monitoring halide ion
concentrations within the dispersing medium. Halide ion is introduced into the dispersing
medium that is at least 50 mol % silver chloride--that is, at least half by number
of the halide ions in the dispersing medium are chloride ions. The pCl of the dispersing
medium is adjusted to favor the formation of {100} grain faces on nucleation--that
is, within the range of from 0.5 to 3.5, preferably within the range of from 1.0 to
3.0 and, optimally, within the range of from 1.5 to 2.5.
[0045] The grain nucleation step is initiated when a silver jet is opened to introduce silver
ion into the dispersing medium. Iodide ion is preferably introduced into the dispersing
medium concurrently with or, optimally, before opening the silver jet. Effective tabular
grain formation can occur over a wide range of iodide ion concentrations ranging up
to the saturation limit of iodide in silver chloride. The saturation limit of iodide
in silver chloride is reported by H. Hirsch, "Photographic Emulsion Grains with Cores:
Part I. Evidence for the Presence of Cores",
J. of Photog. Science, Vol. 10 (1962), pp. 129-134, to be 13 mol %. In silver halide grains in which equal
molar proportions of chloride and bromide ion are present up to 27 mol % iodide, based
on silver, can be incorporated in the grains. It is preferred to undertake grain nucleation
and growth below the iodide saturation limit to avoid the precipitation of a separate
silver iodide phase and thereby avoid creating an additional category of unwanted
grains. It is generally preferred to maintain the iodide ion concentration in the
dispersing medium at the outset of nucleation at less than 10 mol %. In fact, only
minute amounts of iodide at nucleation are required to achieve the desired tabular
grain population. Initial iodide ion concentrations of down to 0.001 mol % are contemplated.
However, for convenience in replication of results, it is preferred to maintain initial
iodide concentrations of at least 0.01 mol % and, optimally, at least 0.05 mol %.
[0046] In the preferred form of the invention, silver iodochloride grain nuclei are formed
during the nucleation step. Minor amounts of bromide ion can be present in the dispersing
medium during nucleation. Any amount of bromide ion can be present in the dispersing
medium during nucleation that is compatible with at least 50 mol % of the halide in
the grain nuclei being chloride ions. The grain nuclei preferably contain at least
70 mol % and optimally at least 90 mol % chloride ion, based on silver.
[0047] Grain nuclei formation occurs instantaneously upon introducing silver ion into the
dispersing medium. For manipulative convenience and reproducibility, silver ion introduction
during the nucleation step is preferably extended for a convenient period, typically
from 5 seconds to less than a minute. So long as the pCl remains within the ranges
set forth above no additional chloride ion need be added to the dispersing medium
during the nucleation step. It is, however, preferred to introduce both silver and
halide salts concurrently during the nucleation step. The advantage of adding halide
salts concurrently with silver salt throughout the nucleation step is that this permits
assurance that any grain nuclei formed after the outset of silver ion addition are
of essentially similar halide content as those grain nuclei initially formed. Iodide
ion addition during the nucleation step is particularly preferred. Since the deposition
rate of iodide ion far exceeds that of the other halides, iodide will be depleted
from the dispersing medium unless replenished.
[0048] Any convenient conventional source of silver and halide ions can be employed during
the nucleation step. Silver ion is preferably introduced as an aqueous silver salt
solution, such as a silver nitrate solution. Halide ion is preferably introduced as
alkali or alkaline earth halide, such as lithium, sodium and/or potassium chloride,
bromide and/or iodide.
[0049] It is possible, but not preferred, to introduce silver chloride or silver iodochloride
Lippmann grains into the dispersing medium during the nucleation step. In this instance
grain nucleation has already occurred and what is referred to above as the nucleation
step is in reality a step for introduction of grain facet irregularities. The disadvantage
of delaying the introduction of grain facet irregularities is that this produces thicker
tabular grains than would otherwise be obtained.
[0050] The dispersing medium contained in the reaction vessel prior to the nucleation step
is comprised of water, the dissolved halide ions discussed above and a peptizer. The
dispersing medium can exhibit a pH within any convenient conventional range for silver
halide precipitation, typically from 2 to 8. It is preferred, but not required, to
maintain the pH of the dispersing medium on the acid side of neutrality (that is,
<7.0). To minimize fog a preferred pH range for precipitation is from 2.0 to 5.0.
Mineral acids, such as nitric acid or hydrochloride acid, and bases, such as alkali
hydroxides, can be used to adjust the pH of the dispersing medium. It is also possible
to incorporate pH buffers.
[0051] The peptizer can take any convenient conventional form known to be useful in the
precipitation of photographic silver halide emulsions and particularly tabular grain
silver halide emulsions. A summary of conventional peptizers is provided in
Research Disclosure, Vol. 308, December 1989, Item 308119, Section IX.
Research Disclosure is published by Kenneth Mason Publications, Ltd., Emsworth, Hampshire P010 7DD, England.
[0052] While synthetic polymeric peptizers of the type disclosed by Maskasky I, cited above
can be employed, it is preferred to employ gelatino peptizers (for example, gelatin
and gelatin derivatives). As manufactured and employed in photography, gelatino peptizers
typically contain significant concentrations of calcium ion, although the use of deionized
gelatino peptizers is a known practice. In the latter instance it is preferred to
compensate for calcium ion removal by adding divalent or trivalent metal ions, such
as alkaline earth or earth metal ions, preferably magnesium, calcium, barium or aluminum
ions. Specifically preferred peptizers are low methionine gelatino peptizers (that
is, those containing less than 30 micromoles of methionine per gram of peptizer),
optimally less than 12 micromoles of methionine per gram of peptizer. However, it
should be noted that the grain growth modifiers of the type taught for inclusion in
these emulsions (for example, adenine) are not appropriate for inclusion in the dispersing
media of this invention, since these grain growth modifiers promote twinning and the
formation of tabular grains having {111} major faces. Generally at least about 10
percent and typically from 20 to 80 percent of the dispersing medium forming the completed
emulsion is present in the reaction vessel at the outset of the nucleation step. It
is conventional practice to maintain relatively low levels of peptizer, typically
from 10 to 20 percent of the peptizer present in the completed emulsion, in the reaction
vessel at the start of precipitation.
[0053] To increase the proportion of thin tabular grains having {100} faces formed during
nucleation, it is preferred that the concentration of the peptizer in the dispersing
medium be in the range of from 0.5 to 6 percent by weight of the total weight of the
dispersing medium at the outset of the nucleation step. It is conventional practice
to add gelatin, gelatin derivatives and other vehicles and vehicle extenders to prepare
emulsions for coating after precipitation. Any naturally occurring level of methionine
can be present in gelatin and gelatin derivatives added after precipitation is complete.
[0054] The nucleation step can be performed at any convenient conventional temperature for
the precipitation of silver halide emulsions. Temperatures ranging from near ambient--for
example, 30
oC up to 90
oC are contemplated, with nucleation temperatures in the range of from 35 to 70
oC being preferred.
[0055] Since grain nuclei formation occurs almost instantaneously, only a very small proportion
of the total silver need be introduced into the reaction vessel during the nucleation
step. Typically from 0.1 to 10 mol % of total silver is introduced during the nucleation
step.
[0056] A grain growth step follows the nucleation step in which the grain nuclei are grown
until tabular grains having {100} major faces of a desired average ECD are obtained.
Whereas the objective of the nucleation step is to form a grain population having
the desired incorporated crystal structure irregularities, the objective of the growth
step is to deposit additional silver halide onto (grow) the existing grain population
while avoiding or minimizing the formation of additional grains. If additional grains
are formed during the growth step, the polydispersity of the emulsion is increased
and, unless conditions in the reaction vessel are maintained as described above for
the nucleation step, the additional grain population formed in the growth step will
not have the desired tabular grain properties described above.
[0057] In its simplest form the process of preparing emulsions according to the invention
can be performed as a single jet precipitation without interrupting silver ion introduction
from start to finish. As is generally recognized by those skilled in the art, a spontaneous
transition from grain formation to grain growth occurs even with an invariant rate
of silver ion introduction, since the increasing size of the grain nuclei increases
the rate at which they can accept silver and halide ion from the dispersing medium
until a point is reached at which they are accepting silver and halide ions at a sufficiently
rapid rate that no new grains can form. Although manipulatively simple, single jet
precipitation limits halide content and profiles and generally results in more polydisperse
grain populations.
[0058] It is usually preferred to prepare photographic emulsions with the most geometrically
uniform grain populations attainable, since this allows a higher percentage of the
total grain population to be optimally sensitized and otherwise optimally prepared
for photographic use. Further, it is usually more convenient to blend relatively monodisperse
emulsions to obtain aim sensitometric profiles than to precipitate a single polydisperse
emulsion that conforms to an aim profile.
[0059] In the preparation of emulsions for the invention it is preferred to interrupt silver
and halide salt introductions at the conclusion of the nucleation step and before
proceeding to the growth step that brings the emulsions to their desired final size
and shape. The emulsions are held within the temperature ranges described above for
nucleation for a period sufficient to allow reduction in grain dispersity. A holding
period can range from a minute to several hours, with typical holding periods ranging
from 5 minutes to an hour. During the holding period relatively smaller grain nuclei
are Ostwald ripened onto surviving, relatively larger grain nuclei, and the overall
result is a reduction in grain dispersity.
[0060] If desired, the rate of ripening can be increased by the presence of a ripening agent
in the emulsion during the holding period. A conventional simple approach to accelerating
ripening is to increase the halide ion concentration in the dispersing medium. When
this approach is employed, it is preferred to increase the chloride ion concentration
in the dispersing medium. That is, it is preferred to lower the pCl of the dispersing
medium into a range in which increased silver chloride solubility is observed. Alternatively,
ripening can be accelerated and the percentage of total grain projected area accounted
for by {100} tabular grains can be increased by employing conventional ripening agents,
such as thioethers and thiocyanates as disclosed by US-A-2,222,264, US-A-2,448,534,
US-A-3,320,069, US-A-3,271,157, US-A-3,574,628 and US-A-3,737,313. More recently crown
thioethers have been suggested for use as ripening agents. Sodium sulfite has also
been demonstrated to be effective in increasing the percentage of total grain projected
accounted by the {100} tabular grains.
[0061] Once the desired population of grain nuclei have been formed, grain growth to obtain
the emulsions for the invention can proceed according to any convenient conventional
precipitation technique for the precipitation of silver halide grains bounded by {100}
grain faces. Whereas iodide and chloride ions are required to be incorporated into
the grains during nucleation and are therefore present in the completed grains at
the internal nucleation site, any halide or combination of halides known to form a
cubic crystal lattice structure can be employed during the growth step. Neither iodide
nor chloride ions need be incorporated in the grains during the growth step, since
the irregular grain nuclei faces that result in tabular grain growth, once introduced,
persist during subsequent grain growth independently of the halide being precipitated,
provided the halide or halide combination is one that forms a cubic crystal lattice.
This excludes only iodide levels above 13 mol % (preferably 6 mol %) in precipitating
silver iodochloride, levels of iodide above 40 mol % (preferably 30 mol %) in precipitating
silver iodobromide, and proportionally intermediate levels of iodide in precipitating
silver iodohalides containing bromide and chloride.
[0062] When silver bromide or silver iodobromide is being deposited during the growth step,
it is preferred to maintain a pBr within the dispersing medium in the range of from
1.0 to 4.2, preferably 1.6 to 3.4. When silver chloride, silver iodochloride, silver
bromochloride or silver iodobromochloride is being deposited during the growth step,
it is preferred to maintain the pCl within the dispersing medium within the ranges
noted above in describing the nucleation step.
[0063] It has been discovered quite unexpectedly that up to 20 percent reductions in tabular
grain thicknesses can be realized by specific halide introductions during grain growth.
Surprisingly, it has been observed that bromide additions during the growth step in
the range of from 0.05 to 15 mol %, preferably from 1 to 10 mol %, based on silver,
produce relatively thinner {100} tabular grains than can be realized under the same
conditions of precipitation in the absence of bromide ion. Similarly, it has been
observed that iodide additions during the growth step in the range of from 0.001 to
<1 mol %, based on silver, produce relatively thinner {100} tabular grains than can
be realized under the same conditions of precipitation in the absence of iodide ion.
[0064] During the growth step both silver and halide salts are preferably introduced into
the dispersing medium. In other words, double jet precipitation is contemplated, with
added iodide salt, if any, being introduced with the remaining halide salt or through
an independent jet. The rate at which silver and halide salts are introduced is controlled
to avoid renucleation--that is, the formation of a new grain population--using known
techniques.
[0065] In the simplest form of the invention the nucleation and growth stages of grain precipitation
occur in the same reaction vessel. It is, however, recognized that grain precipitation
can be interrupted, particularly after completion of the nucleation stage. Further,
two separate reaction vessels can be substituted for the single reaction vessel described
above.
[0066] It is herein contemplated that various parameters important to the control of grain
formation and growth, such as pH, pAg, ripening, temperature, and residence time,
can be independently controlled in separate nucleation and growth reaction vessels.
To allow grain nucleation to be entirely independent of grain growth occurring in
the growth reaction vessel down stream of the nucleation reaction vessel, no portion
of the contents of the growth reaction vessel should be recirculated to the nucleation
reaction vessel. Preferred arrangements that separate grain nucleation from the contents
of the growth reaction vessel are disclosed by US-A-4,334,012 (that also discloses
the useful feature of ultrafiltration during grain growth), US-A-4,879,208 and EP-A-O-326,852,
EP-A-O-326,853, EP-A-O-355,535 and EP-A-O-370,116, and EP-A-O-0 368 275, published
EP-A-0 374 954.
[0067] Although the process of grain nucleation has been described above in terms of utilizing
iodide to produce the crystal irregularities required for tabular grain formation,
alternative nucleation procedures have been devised, demonstrated in the Examples
below, that eliminate any requirement of iodide ion being present during nucleation
in order to produce tabular grains. These alternative procedures are, further, compatible
with the use of iodide during nucleation. Thus, these procedures can be relied upon
entirely during nucleation for tabular grain formation or can be relied upon in combination
with iodide ion during nucleation to product tabular grains.
[0068] It has been observed that rapid grain nucleations, including so-called dump nucleations,
in which significant levels of dispersing medium supersaturation with halide and silver
ions exist at nucleation accelerate introduction of the grain irregularities responsible
for tabularity. Since nucleation can be achieved essentially instantaneously, immediate
departures from initial supersaturation to the preferred pCl ranges noted above are
entirely consistent with this approach.
[0069] In a preferred embodiment, the high silver chloride tabular grains useful in the
practice of this invention are further characterized in that such grains are comprised
of a core and a surrounding band containing a higher level of iodide ions and containing
up to about 30 percent of the silver in the tabular grain. Such grains are described
in US-A-5,314,798.
[0070] It has also been observed that maintaining the level of peptizer in the dispersing
medium during grain nucleation at a level of less than 1 percent by weight enhances
of tabular grain formation. It is believed that coalescence of grain nuclei pairs
can be at least in part responsible for introducing the crystal irregularities that
induce tabular grain formation. Limited coalescence can be promoted by withholding
peptizer from the dispersing medium or by initially limiting the concentration of
peptizer. US-A-4,334,012 illustrates grain nucleation in the absence of a peptizer
with removal of soluble salt reaction products to avoid coalescence of nuclei. Since
limited coalescence of grain nuclei is considered desirable, the active interventions
of Mignot to eliminate grain nuclei coalescence can be either eliminated or moderated.
It is also contemplated to enhance limited grain coalescence by employing one or more
peptizers that exhibit reduced adhesion to grain surfaces. For example, it is generally
recognized that low methionine gelatin is less tightly absorbed to grain surfaces
than gelatin containing higher levels of methionine. Further moderated levels of grain
adsorption can be achieved with so-called "synthetic peptizers"--that is, peptizers
formed from synthetic polymers. The maximum quantity of peptizer compatible with limited
coalescence of grain nuclei is, of course, related to the strength of adsorption to
the grain surfaces. Once grain nucleation has been completed, immediately after silver
salt introduction, peptizer levels can be increased to any convenient conventional
level for the remainder of the precipitation process.
[0071] The emulsions for this invention include silver chloride, silver iodochloride emulsions,
silver iodobromochloride emulsions and silver iodochlorobromide emulsions. Dopants,
in concentrations of up to 10
-2 mol per silver mol and typically less than 10
-4 mol per silver mol, can be present in the grains. Compounds of metals such as copper,
thallium, lead, mercury, bismuth, zinc, cadmium , rhenium, and Group VIII metals (for
example, iron, ruthenium, rhodium, palladium, osmium, iridium, and platinum) can be
present during grain precipitation, preferably during the growth stage of precipitation.
Coordination ligands, such as halo, aquo, cyano cyanate, thiocyanate, nitrosyl, thionitrosyl,
oxo and carbonyl ligands are contemplated and can be relied upon to modify photographic
properties.
[0072] Dopants and their addition are illustrated, for example, by US-A-1,195,432; US-A-1,951,933;
US-A-2,448,060; US-A-2,628,167; US-A-2,950,972; US-A-3,287,136; US-A-3,488,709; US-A-3,687,676;
US-A-761,267; US-A-3,790,390; US-A-US-A-3,890,154; US-A-3,901,711; US-A-4,173,483;
US-A-4,269,927; US-A-4,835,093; US-A-4,933,272, 4,981,781, and 5,037,732; US-A-4,945,035;
and US-A-5,024,931.
[0073] The invention is particularly advantageous in providing high silver chloride (greater
than 50 mol % silver chloride) tabular grain emulsions, since conventional high silver
chloride tabular grain emulsions having tabular grains bounded by {111} are inherently
unstable and require the presence of a morphological stabilizer to prevent the grains
from regressing to nontabular forms. Particularly preferred high silver chloride emulsions
are those that contain more than 70 mol % (optimally more than 90 mol %) silver chloride.
[0074] Although not essential to the practice of the invention, a further procedure that
can be employed to maximize the population of tabular grains having {100} major faces
is to incorporate an agent capable of restraining the emergence of non-{100} grain
crystal faces in the emulsion during its preparation. The restraining agent, when
employed, can be active during grain nucleation, during grain growth or throughout
precipitation.
[0075] Useful restraining agents under the contemplated conditions of precipitation are
organic compounds containing a nitrogen atom with a resonance stabilized p electron
pair. Resonance stabilization prevents protonation of the nitrogen atom under the
relatively acid conditions of precipitation.
[0076] In one preferred form the restraining agent can satisfy the following formula:

where
Z represents the atoms necessary to complete a five or six membered aromatic ring
structure, preferably formed by carbon and nitrogen ring atoms. Preferred aromatic
rings are those that contain one, two or three nitrogen atoms. Specifically contemplated
ring structures include 2H-pyrrole, pyrrole, imidazole, pyrazole, 1,2,3-triazole,
1,2,4-triazole, 1,3,5-triazole, pyridine, pyrazine, pyrimidine, and pyridazine.
[0077] When the stabilized nitrogen atom is a ring substituent, preferred compounds satisfy
the following formula:

where
Ar is an aromatic ring structure containing from 5 to 14 carbon atoms and
R
1 and R
2 are independently hydrogen, Ar, or any convenient aliphatic group or together complete
a five or six membered ring. Ar is preferably a carbocyclic aromatic ring, such as
phenyl or naphthyl. Alternatively any of the nitrogen and carbon containing aromatic
rings noted above can be attached to the nitrogen atom of formula II through a ring
carbon atom. In this instance, the resulting compound satisfies both formulae I and
II. Any of a wide variety of aliphatic groups can be selected. The simplest contemplated
aliphatic groups are alkyl groups, preferably those containing from 1 to 10 carbon
atoms and most preferably from 1 to 6 carbon atoms. Any functional substituent of
the alkyl group known to be compatible with silver halide precipitation can be present.
It is also contemplated to employ cyclic aliphatic substituents exhibiting 5 or 6
membered rings, such as cycloalkane, cycloalkene and aliphatic heterocyclic rings,
such as those containing oxygen and/or nitrogen hetero atoms. Cyclopentyl, cyclohexyl,
pyrrolidinyl, piperidinyl, furanyl and similar heterocyclic rings are specifically
contemplated.
[0078] Selection of preferred restraining agents and their useful concentrations can be
accomplished by the following selection procedure: The compound being considered for
use as a restraining agent is added to a silver chloride emulsion consisting essentially
of cubic grains with a mean grain edge length of 0.3 mm. The emulsion is 0.2 molar
in sodium acetate, has a pCl of 2.1, and has a pH that is at least one unit greater
than the pKa of the compound being considered. The emulsion is held at 75
oC with the restraining agent present for 24 hours. If, upon microscopic examination
after 24 hours, the cubic grains have sharper edges of the {100} crystal faces than
a control differing only in lacking the compound being considered, the compound introduced
is performing the function of a restraining agent. The significance of sharper edges
of intersection of the {100} crystal faces lies in the fact that grain edges are the
most active sites on the grains in terms of ions reentering the dispersing medium.
By maintaining sharp edges the restraining agent is acting to restrain the emergence
of non-{100} crystal faces, such as are present, for example, at rounded edges and
corners. In some instances instead of dissolved silver chloride depositing exclusively
onto the edges of the cubic grains a new population of grains bounded by {100} crystal
faces is formed. Optimum restraining agent activity occurs when the new grain population
is a tabular grain population in which the tabular grains are bounded by {100} major
crystal faces.
[0079] It is specifically contemplated to deposit epitaxially silver salt onto the tabular
grains acting as hosts. Conventional epitaxial depositions onto high chloride silver
halide grains are well known in the art.
[0080] Any color developing agent that is suitable for use with low silver iodide, silver
chloride containing elements may be utilized with this invention. These color developing
agents are well known and widely used in a variety of color photographic processes.
They include aminophenols and p-phenylenediamines. While the concentration of developing
agent to be employed in the practice of this invention can be any concentration known
in the art, it is preferred that the concentration be between about 1.0 and 200 mmol/liter,
with a concentration range between about 5 and 100 mmol/liter being preferred, a range
between about 10 and 80 mmol/liter being more preferred and a concentration range
between about 10 and 60 mmol/liter being most preferred. While the paraphenylene diamine
developing agent is typically added to the developing solution directly, it may also
provided by incorporation in a blocked form directly in the light sensitive color
element as described in US-A-5,256,525. Alternatively, the blocked form of the developer
may be employed in a replenisher element as described in US-A-5,302,498.
[0081] In addition to the primary aromatic amino color developing agent, the color developing
solutions used with this invention may contain a variety of other agents such as alkalies
to control pH, bromides, iodides, benzyl alcohol, anti-oxidants, anti-foggants, solubilizing
agents (such as para-toluene sulfonic acid), brightening agents, competing couplers
and so forth.
[0082] The photographic color developing compositions may be employed in the form of aqueous
alkaline working solutions having a pH of above 7 and preferably in the range of from
9 to 13. The developer solution is more preferably maintained at a pH between 9 and
12 and most preferably maintained at a pH between 9.5 and 11.5. To provide the necessary
pH, they may contain one or more of the well known and widely used pH buffering agents,
such ash the alkali metal carbonates or phosphates. Potassium carbonate is especially
preferred.
[0083] The contact time of the photographic element with the developer solution is between
5 and 150 seconds. Preferably, the contact time is between 10 and 120 seconds and
most preferably the contact time is between 15 and 105 seconds.
[0084] The temperature of the development solution is typically regulated using means well
known in the art at between 25 °C and 65 °C. Preferably, the temperature is maintained
at between 30 °C and 60 °C. and most preferably the temperature is maintained at between
35 °C and 60 °C.
[0085] The developer solution useful in the practice of this invention comprises bromide
ion that can be provided as any of the known bromide salts including but not limited
to potassium bromide, sodium bromide, lithium bromide and ammonium bromide. The bromide
ion concentration is maintained at a level greater than 0.18 mmol/liter. While a bromide
ion concentration between 0.25 and 50 mmol/liter may be employed, a bromide ion concentration
between 1 and 28 mmol/liter is preferred, and a bromide ion concentration between
2 mmol/liter and 20 mmol/liter is even more preferred. Lower levels of bromide ion
lead to an unsatisfactory imbalance in the extent of development of overlying and
underlying layers in a multilayer, multicolor photographic element while higher levels
of bromide can cause unwanted restraint of development. The higher levels of developer
solution bromide ion useful in the practice of this invention are enabled by the surprisingly
low extent of bromide for chloride ion metathesis encountered when developing the
high silver chloride 〈100〉 tabular grain emulsions required for the practice of this
invention in the developer solutions of this invention.
[0086] It is additionally useful to control the balance of developing agent and bromide
ion in the practice of this invention. Most generally, the ratio of the concentration
of developing agent to bromide ion should be between 60:1 and 0.5:1. It is preferable
that the ratio of developing agent to bromide ion concentration be between 50:1 and
0.8:1 and more preferable that this ratio be between 40:1 and 0.9:1. It is most preferred
that the ratio of developing agent concentration to bromide ion concentration in the
developing solution be between 30:1 and 1:1.
[0087] These, and all other characteristics of process solutions and concentrations of components
in process solutions mentioned throughout should be determined just before the light
sensitive element comes into contact with the processing solution. The contact time
of an element with a process solution is the time elapsed from when the element first
contacts the process solution to when the element is withdrawn from contact with the
same process solution.
[0088] The developer solutions useful in the practice of this invention may additionally
contain chloride ion. Chloride ion concentrations of between 0 and 300 mmol/liter
are useful, with chloride ion concentrations between 0 and 100 mmol/liter being preferred.
On extended use of the developer solution to develop high chloride emulsions, chloride
levels of between 15 and 80 mmol/liter may be typically encountered. Additionally,
the developer solutions useful in the practice of this invention may include iodide
ion as known in the art. Trace quantities of iodide ion at concentrations between
0 and 0.1 mmol/liter are contemplated with iodide concentrations less than 0.01 mmol/liter
being preferred.
[0089] Antioxidants such as hydroxylamine, dialkyl hydroxylamines, alkylsulfonate hydroxylamines,
amidoalkylhydroxylamines, alkoxyalkylhydroxylamines, alkanolamines, hydrazines and
aminocarboxylic acids are additionally useful in the developer solutions at any concentration
known in the art. While hydroxylamine is believed to behave as a mild developer for
silver chloride emulsions, the halide ion incorporated in the developer solutions
may generally be adequate to ameliorate such activity. The dialkyl hydroxylamines,
alkanolamines and aminocarboxylic acids can be employed when such activity is objectionable.
Useful dialkyl hydroxylamines (substituted and unsubstituted), alkanolamines, hydrazines
and aminocarboxylic acids are well know in the art and include diethyl hydroxylamine,
ethanolamine and glycine as well as those illustrated at US-A-3,287,125; US-A-3,362,961;
US-A-4,892,804; US-A-5,071,734; US-A-4,923,786; US-A-4,800,153; US-A-4,801,516; US-A-4,814,260;
US-A-4,876,174; US-A-4,965,176; US-A-4,966,834; US-A-5,153,111; and US-A-5,354,646.
[0090] A useful antioxidant is bis(ethylsulfonato) hydroxylamine.
[0091] The total quantity of amine antioxidants is preferably between 0.5 and 10 moles of
antioxidant per mol of paraphenylene diamine developing agent. Inorganic antioxidants
as known in the art such as sulfite ion, bisulfite ion and the like are also useful.
Typically these inorganic antioxidants are employed at art known useful concentrations.
For example, less than 50 mmol/liter of sulfite or sulfite equivalent is generally
found to be useful, with concentrations of less than 16 mmol/liter being preferred.
It may additionally be useful to incorporate sequestering agents for iron, calcium
and the like, examples being aromatic polyhydroxy compounds, aminopolyphosphonic acids
and aminopolycarboxylic acids. Additional compounds to improve clarity of the developer
solution such as sulfonated polystyrenes as well as antistaining agents and wetting
agents, all as disclosed in US-A-4,892,804 are also recommended.
[0092] A typical developer solution useful in the practice of this invention may be formulated
from 800 ml of water, 34.3 g of anhydrous potassium carbonate, 2.32 g of potassium
bicarbonate, 0.38 g of anhydrous sodium sulfite, 2.96 g of sodium metabisulfite, 1.2
mg of potassium iodide, 1.31 g of sodium bromide, 8.43 g of diethylenetriaminepentaacetic
acid pentasodium salt supplied as a 40% solution, 2.41 g of hydroxylamine sulfate,
4.52 g of N-(4-amino-3-methylphenyl)-N-ethyl-2-aminoethanol) as its sulfuric acid
salt, and sufficient additional water and acid or base to make 1 liter of solution
at a pH of 10.00 +/-0.05 at 26.7 °C.
[0093] Another typical developer useful in the practice of this invention may be formulated
from 800 ml of water, 11 ml of 100% triethanolamine, 0.25 ml of 30% lithium polystyrene
sulfonate, 0.24 g of anhydrous potassium sulfite, 2.3 g of Blankophor REU, 2.7 g of
lithium sulfate, 0.8 ml of 60% 1-hydroxyethyl-1,1-diphosphonic acid, 1.8 g of potassium
chloride, 0.3 g of potassium bromide, 25 g of potassium carbonate, 6 ml of 85% N,N-diethylhydroxylamine,
4.85 g of N-(4-amino-3-methylphenyl)-N-ethyl-2-aminoethyl-methanesulfonamide as its
sesquisulfate hydrate salt, and sufficient additional water and acid or base to make
1 liter of solution at a pH of 10.12 +/- 0.05 at 25 °C.
[0094] Yet another typical developer useful in the practice of this invention may be formulated
from 800 ml of water, 5.5 ml of 100% triethanolamine, 0.25 ml of 30% lithium polystyrene
sulfonate, 0.5 ml of 45% potassium sulfite, 1 g of Blankophor REU, 2 g of lithium
sulfate, 0.6 ml of 60% 1-hydroxyethyl-1,1-diphosphonic acid, 0.6 ml of 40% diethylenetriaminepentaacetic
acid pentasodium salt, 6 g of potassium chloride, 0.8 g of potassium bromide, 25 g
of potassium carbonate, 3 ml of 85% N,N-diethylhydroxylamine, 3.8 g of N-(4-amino-3-methylphenyl)-N-ethyl-2-aminoethyl-methanesulfonamide
as its sesquisulfate hydrate salt, and sufficient additional water and acid or base
to make 1 liter of solution at a pH of 10.10 +/- 0.05 at 25 °C.
[0095] Another useful developer may be formulated from 800 ml of water, 1 ml of 40% aminotris(methylenephosphonic
acid) pentasodium salt, 4.35 g of anhydrous sodium sulfite, 1.72 g of anhydrous sodium
bromide, 17.1 g of sodium carbonate monohydrate, 2.95 g of 4-N,N-diethyl-2-methylphenylenediamine
as its hydrochloric acid salt, and sufficient additional water and acid or base to
make 1 liter of solution at a pH of 10.53 +/- 0.05 at 26.7 °C.
[0096] An additional useful developer may be formulated from 600 ml of water, 2 ml of 40%
aminotris(methylenephosphonic acid) pentasodium salt, 2 g of anhydrous sodium sulfite,
1.2 g of anhydrous sodium bromide, 30 g of sodium carbonate monohydrate, 0.22 g of
3,5-dinitrobenzoic acid, 4 g of N-(4-amino-3-methylphenyl)-N-ethyl-2-aminoethyl-methanesulfonamide
as its sesquisulfate hydrate salt, 0.17 ml of sulfuric acid, and sufficient additional
water and acid or base to make 1 liter of solution at a pH of 10.20 +/- 0.05 at 26.7
°C.
[0097] The photographic elements described herein are desilvered after color development
is performed. Desilvering can be performed by one of the following methods (i) a method
using a bleaching solution bath and fixing solution bath; (ii) a method using a bleaching
solution bath and a blixing solution bath; (iii) a method using a blixing solution
and a fixing solution bath ; and (iv) a method using a single blixing bath. Blixing
may be preferred in order to shorten the process time.
[0098] Examples of bleaching agents that may be used in the bleach solutions or blix solutions
of the current invention are ferric salts, persulfate, dichromate, bromate, red prussiate,
and salts of aminopolycarboxylic acid ferric complexes, with salts of aminopolycarboxylic
acid ferric complexes being preferred.
[0099] Preferred aminopolycarboxylic acid ferric complexes are listed below:
(1) ethylenediaminetetraacetic acid ferric complex;
(2) diethylenetriaminepentaacetic acid ferric complex;
(3) cyclohexanediaminetetraacetic acid ferric complex;
(4) iminodiacetic acid ferric complex;
(5) methyliminodiacetic acid ferric complex;
(6) 1,3-diaminopropanetetraacetic acid ferric complex;
(7) glycoletherdiaminetetraacetic acid ferric complex;
(8) β-alanine diacetic acid ferric complex;
(9) iso-serine diacetic acid ferric complex; and
(10) ethylenediaminedisuccinic acid ferric complex.
[0100] These complexes can be used alone or in mixture as known in the art. These aminopolycarboxylic
acid ferric complexes are used in the form of a sodium salt, potassium salt, or ammonium
salt. An ammonium salt may be preferred for speed, with alkali salts being preferred
for environmental reasons.
[0101] The content of the salt of an aminopolycarboxylic acid ferric complex in the bleaching
solutions and blixing solutions of this invention is 0.05 to 1 mol/liter. The pH range
of the bleaching solution is 2.5 to 7, and preferably 4.0 to 7.
[0102] The bleaching solution or the blixing solution can contain rehalogenating agents,
one or more inorganic and organic acids or alkali metal or ammonium salts thereof,
a pH buffer, or corrosion inhibitors.
[0103] Examples of fixing agents that may be used in the this invention are water-soluble
solvents for silver halide such as: a thiosulfate, a thiocyanate, a thioether compound
and a thiourea. These fixing agents can be used singly or in a combination of at least
two agents. Thiosulfate is preferably used in the present invention.
[0104] The content of the fixing agent per liter is preferably 0.1 to 2 mol. The pH range
of the blixing or fixing solution is preferably 3 to 10 and more preferably 5 to 9.
[0105] In order to adjust the pH of the fixing solution, hydrochloric acid, sulfuric acid,
nitric acid, acetic acid, bicarbonate, ammonia, potassium hydroxide, sodium hydroxide,
sodium carbonate, potassium carbonate, may be added.
[0106] The blixing and the fixing solution may also contain a preservative such as a sulfite
or a metabisulfite. The content of these compounds is from 0 to 0.50 mol/liter, and
more preferably 0.02 to 0.40 mol/liter as an amount of sulfite ion. Ascorbic acid,
a carbonyl bisulfite, acid adduct, or a carbonyl compound may also be used as a preservative.
[0107] The photographic elements described herein may be bleached or blixed with a solution
comprising, as the bleaching agent, a ferric complex of an alkyliminodiacetic acid,
the alkyl group of which contains from 1 to 6 carbon atoms. Methyliminodiacetic acid
is among the preferred ligands. These bleaching and blixing solutions and their use
are further described in US-A-4,294,914.
[0108] Blixing solutions comprising ternary ferric-complex salts can also be employed.
[0109] The photographic elements described herein may be blixed in a solution in which the
bleaching agent is an iron(III) complex with beta-alaninediacetic acid (HOOCCH
2CH
2N(CH
2COOH)
2)(ADA). The blixing solution is pH adjusted between 4.5 and 7.0 and contains thiosulfate.
The blixing solution further contains at least about 50 mol % ADA per mol ferric ion,
preferably at least 80 mol % ADA, and more preferably 1 to 120 mol % excess free ADA.
These blixing solutions and their use are further described in DE 4,031,757 A1. The
same bleaching agent and closely related bleaching agents may be used in bleaching
compositions to process the photographic elements of this invention. For example,
a bleach bath may contain a Fe(III) complex, the complexing agent of which represents
at least 20 mol % of ADA or glycinedipropionic acid (HOOCCH
2N (CH
2CH
2COOH)
2)(GDPA) or closely related complexing agents.
[0110] The photographic elements described herein may be bleached in a bleaching solution
consisting essentially of an aqueous solution having a pH of at least 7, that contains
a peroxy compound, a buffering agent, and a polyacetic acid that contains at least
three carboxyl groups and is selected from the group consisting of aminopolyacetic
acids and thiopolyacetic acids. The preferred pH range is from 8 to 10. The preferred
peroxy compound is hydrogen peroxide. The preferred buffering agents are selected
from the group consisting of hydroxides, borates, phosphates, carbonates and acetates.
The polyacetic acid is preferably selected from the group consisting of 2-hydroxy-trimethylenedinitrilo
tetraacetic acid, 1,2-propanediaminetetraacetic acid, ethanediylidenetetrathio tetraacetic
acid, ethylenedinitrilotetraacetic acid, cyclohexylenedinitrilo tetraacetic acid,
nitrilotriacetic acid, and diethylenetriamine pentaacetic acid; and more preferably
2-hydroxy-trimethylenedinitrilo tetraacetic acid.
[0111] The photographic elements described herein may be blixed in a blixing solution containing
an aqueous alkaline solution of a peroxy compound and an ammonium or amine salt of
a weak acid selected from the group consisting of carbonic acid, phosphoric acid,
sulfurous acid, boric acid, formic acid, acetic acid, propionic acid and succinic
acid. A pH range from 8 to 12 is preferred, with a pH from 9 to 11 being more preferred.
Preferred peroxy compounds are hydrogen peroxide, an alkali metal perborate or an
alkali metal percarbonate. The preferred salt of a weak acid is ammonium carbonate.
[0112] The photographic elements described herein may be bleached or blixed with bleaching
or bleach-fixing solutions containing at least one of hydrogen peroxide and a compound
capable of releasing hydrogen peroxide, and at least one water-soluble chloride. The
water soluble chloride is preferably an alkali metal salt or a quaternary ammonium
salt and preferably is present at 0.005 to 0.3 moles per liter. The bleaching or blixing
solutions also preferably contain an organic phosphonic acid or a salt thereof, more
preferably of the type R
1N(CH
2PO
3M
2)
2, wherein M represents a hydrogen atom or a cation imparting water solubility (for
example, alkali metal such as sodium and potassium; ammonium, pyridinium, triethanolammonium
or triethylammonium ion); and R
1 represents an alkyl group having from 1 to 4 carbon atoms, an aryl group, an araalkyl
group, an alicyclic group, or a heterocyclic group each of which may be substituted
with a hydroxyl group, an alkoxy group, a halogen atom, -PO
3M
2, -CH
2PO
3M
2 or -N(CH
2PO
3M
2)
2; or of the type (R
2R
3C(PO
3M
2)
2), where R
2 represents a hydrogen atom, an alkyl group, an aralkyl group, an alicyclic group,
a heterocyclic group or an alkyl group, or -PO
3M
2; and R
3 represents a hydrogen atom, a hydroxyl group, an alkyl group, or a substituted alkyl
group or -PO
3M
2 . The organic phosphonic acid or salt thereof is preferably present at a concentration
from 10 mg/liter. The pH of the solutions are in the range of 7 to 13, and more preferably
8 to 11.
[0113] The photographic elements described herein may be developed and bleached by a method
of processing that includes a redox-amplification dye image-forming step and a bleach
step using an aqueous solution of hydrogen peroxide or a compound capable of releasing
hydrogen peroxide. The preferred pH of the bleach solution is from 1 to 6, more preferably
from 3 to 5.5. The photographic elements may further be fixed in a sulfite fixer with
or without a low level of thiosulfate (for example, 60 g Na
2SO
3/liter and 2 g Na
2S
2O
3/liter). This processing method is further described in WO 92/01972.
[0114] The photographic elements described herein may be bleached in a bleaching solution
containing hydrogen peroxide, or a compound that releases hydrogen peroxide, and halide
ions and that has a pH in the range of 5 to 11. Chloride ion is the preferred halide
and is preferably present at 0.52 to 1 g /liter. These bleaching solutions and their
use are further described in WO 92/07300.
[0115] The photographic elements described herein may be fixed in an aqueous fixing solution
containing a concentration of from 5 to 200 g/liter of an alkali metal sulfite as
the sole silver halide solvent. The alkali metal sulfite is preferably 10 to 150 g/liter
of anhydrous sodium sulfite. The fixer bath pH is preferably greater than 6. It is
preferred to use a silver chloride forming bleaching step prior to the fixing step.
[0116] The photographic elements described herein may be fixed in a fixing solution that
has a thiosulfate concentration from 0.05 to 3.0 molar and an ammonium concentration
of 0.0 to 1.2 molar, preferably less than 0.9 molar, and more preferably essentially
absent. In this embodiment the photographic elements preferably have a silver halide
content of less than 7.0 g/m
2 based on silver and an iodide content of less than about 0.35 g/m
2. Further, they preferably contain an emulsion containing from about 0.2 to 3.0 g/m
2, based on silver, of a silver halide emulsion in which greater than 50% of the projected
surface area is provided by tabular grains having a tabularity between 50 and 25,000.
[0117] The photographic elements described herein may be bleached by contacting them with
a persulfate bleach solution in the presence of an accelerating amount of a complex
of ferric ion and a 2-pyridinecarboxylic acid or a 2,6-pyridinedicarboxylic acid.
The complex of ferric ion and a 2-pyridinecarboxylic acid or a 2,6-pyridinedicarboxylic
acid may be contained in the bleach itself, a prebleach or in the photographic element.
The persulfate is preferably sodium persulfate. The 2-pyridinecarboxylic acid or 2,6-pyridinedicarboxylic
acid is of the formula:

wherein X
1, X
2, X
3 and X
4 are independently H, OH, CO
2M, SO
3M, or PO
3M, and M is H or an alkali metal cation. Most preferably X
1, X
2, X
3 and X
4 are H. When contained in the bleaching solution the concentration of the ferric ion
is preferably 0.001 to 0.100 molar and the concentration of the 2-pyridinecarboxylic
acid or 2,6-pyridinedicarboxylic acid is 0.001 to 0.500 molar.
[0118] Peracid bleaches may be especially useful with the originating photographic elements
of this invention when the color silver halide photographic element has a speed greater
than ISO 180 or contains at least one spectrally sensitized silver halide emulsion
with a tabularity greater than 100, and when the photographic element comprises a
total amount of incorporated silver and incorporated vehicle of 20 g/m
2 film or less. The developed photographic element should be bleached in the presence
of a bleach accelerator. Preferably the peracid is a sodium, potassium, or ammonium
persulfate bleach and the amount of silver in the photographic element is less than
10 g/m
2 of film. These bleaches and photographic elements are further described in US-A-5,318,880.
[0119] The photographic elements may also be desilvered by bleaching the photographic element
with a peracid bleach, and subsequently contacting the photographic element with a
fixer solution comprising thiosulfate anion and sodium cation. This is particularly
useful in the following embodiments:
(1) when the product of the contact time of the photographic element with the fixer
solution and the molar concentration of the thiosulfate anion divided by the proportion
of the sodium cation as counterion (Molar-minute fixing time) is less than 1.9 Molar-minutes.
More preferably the Molar-minute fixing time is less than 0.825 Molar-minutes. The
preferred peracid bleach is a persulfate or peroxide, with sodium persulfate being
most preferred. Preferably the fixer solution has an ammonium cation concentration
of less than 0.8 molar, and more preferably the fixer solution is substantially free
of ammonium cation. It is preferred that the proportion of sodium cation as counterion
is greater than 50 %; and
(2) when the photographic element has a silver content of less than 7.0 g/m2; and the fixer solution has an ammonium ion content of less than 1.4 molar. The preferred
peracid bleach is a persulfate or peroxide, with sodium persulfate being most preferred.
Preferably the fixer solution has an ammonium cation concentration of less than 0.9
molar, and more preferably the fixer solution is substantially free of ammonium cation.
It is preferred that the photographic element comprises at least one silver halide
emulsion in which greater than 50% of the projected surface area is provided by tabular
grains having a tabularity between 50 and 25,000. It is also preferred that the photographic
element has a silver content of less than 6.0 g/m2.
[0120] The photographic elements may also be processed in KODAK Process ECN and ECP, that
are described in Kodak H-24.07 "Manual for Processing Eastman Motion Picture Films,
Module 7"(ECN) and Kodak H-24.09 "Manual for Processing Eastman Color Films, Module
9" (ECP), available from Eastman Kodak Company, Department 412-L, Rochester, New York.
[0121] It is specifically contemplated to process, that is, develop, stop, bleach, wash,
fix, blix or stabilize, the elements of this invention by immersing the elements in
a processing solution and applying the solution to the surface of the photosensitive
layers of the elements as a jet-stream while the element is immersed in the solution.
When this jet-stream method is employed, the preferred time of contact of a process
solution with the photographic element may be greatly shortened, often by as much
as 90%. Development by this method is described in US-A-5,116,721.
[0122] The photographic elements may additionally be employed with rapid acting bleaches
and fixes known in the art and often commercially employed in minilabs. The rapid
bleaching and fixing solutions, their regeneration, replenishment and use described
at "Fujicolor Negative Films, Process CN-16FA", publication AF3-699E, available from
the Fuji Photo Company, and the rapid bleaching and fixer solutions, and their regeneration,
replenishment and use described at "Using KODAK Chemicals in Minilabs", publication
Z-100 available from the Eastman Kodak Company are specifically contemplated.
[0123] If the photographic elements are to be desilvered, then the contact time of the exposed
and developed element with a bleach, fixer, bleach-fix, wash, accelerator or stabilizer
solution can be any time known in the art. The purposes of the invention are best
served by limiting this contact time. Accordingly, the contact time of the element
with any of these solutions will generally not individually exceed 240 seconds. Preferably,
these individual contact times will be less than 120 or 90 seconds, and more preferably,
these individual contact times will be less than 60, 30, 20 or even 10 seconds. When
sequential desilvering solutions are employed, any total contact time useful to enable
desilvering is contemplated. It is preferred that this total contact time not exceed
240 seconds, more preferred that it not exceed 120 or 90 seconds and most preferred
that it not exceed 60 or even 30 seconds.
[0124] Desilvering of the exposed and developed element can be aided by any of the bleach,
fixer or bleach-fix catalysts or accelerants known in the art. These catalysts or
accelerants may be employed in a blocked or unblocked form and may be initially present
in the element itself, or in any of the solutions that the element contacts during
the course of development or desilvering.
[0125] It is specifically contemplated to replenish the working development, desilvering
and auxiliary solutions as known in the art so as to maintain their useful compositions
during continuous running. In a preferred embodiment these replenishment solutions
are supplied at a rate of less than about 450 ml per square meter of processed film.
It is even more preferred that the replenishment solutions be supplied at a rate of
between 10 and 300 ml per square meter of processed film and most preferred that the
replenisher solution be supplied at a rate of between 30 and 200 ml per square meter
of processed film. When a bleach-fix replenisher is so supplied, it is preferred that
the bleach-fix replenisher not contain 1,2,4-triazole-3-thiol or a derivative as an
accelerant.
[0126] The emulsions used in this invention can be chemically sensitized with active gelatin
as illustrated by T. H. James,
The Theory of the Photographic Process, 4th Ed., Macmillan, 1977, pp. 67-76, or with sulfur, selenium, tellurium, gold,
platinum, palladium, iridium, osmium, rhenium or phosphorus sensitizers or combinations
of these sensitizers, such as at pAg levels of from 5 to l0, pH levels of from 5 to
8 and temperatures of from 30 to 80
oC, as illustrated by
Research Disclosure, Vol. l20, April, 1974, Item l2008,
Research Disclosure, Vol. l34, June, 1975, Item l3452, US-A-l,623,499, US-A-l,673,522, US-A-2,399,083,
US-A-2,642,36l, US-A-3,297,447, US-A-3,297,446, U.K. Patent l,3l5,755, US-A-3,772,03l,
US-A-3,76l,267, US-A-3,857,7ll, US-A-3,565,633, US-A-3,90l,7l4 and US-A-3,904,4l5,and
other literature too numerous to mention.
[0127] The emulsions can be spectrally sensitized with dyes from a variety of classes, including
the polymethine dye class, that includes the cyanines, merocyanines, complex cyanines
and merocyanines (that is, tri-, tetra- and polynuclear cyanines and merocyanines),
styryls, merostyryls, streptocyanines, hemicyanines, arylidenes, allopolar cyanines
and enamine cyanines.
[0128] To avoid instability in emulsion coatings, stabilizers and antifoggants can be employed,
as is known in the art.
[0129] The emulsions can be protected from fog and desensitization caused by trace amounts
of metals such as copper, lead, tin, iron and the like by incorporating known addenda.
[0130] Where the color photographic element of this invention is to be processed at elevated
bath or drying temperatures pressure desensitization and/or increased fog can be controlled
by selected combinations of addenda, vehicles, hardeners and/or processing conditions
as illustrated by US-A-3,295,976, US-A-3,545,97l, US-A-3,708,303, US-A-3,6l5,619,
US-A-3,623,873, US-A-3,67l,258, US-A-3,79l,830,
Research Disclosure, Vol. 99, July, 1972, Item 9930, US-A-3,843,364, US-A-3,867,l52, US-A-3,967,965 and
US-A-3,947,274 and US-A-3,954,474.
[0131] Apart from the features that have been specifically discussed previously for the
tabular grain emulsion preparation procedures and the tabular grains that they produce,
their further use in the color photographic elements of this invention can take any
convenient conventional form. Substitution in color photographic elements for conventional
emulsions of the same or similar silver halide composition is generally contemplated,
with substitution for silver halide emulsions of differing halide composition, particularly
other tabular grain emulsions, being also feasible. The low levels of native blue
sensitivity of the high silver chloride {100} tabular grain emulsions allows the emulsions
to be employed in any desired layer order arrangement in multicolor photographic elements,
including any of the layer order arrangements disclosed by US-A-4,439,520, both for
layer order arrangements and for other conventional features of photographic elements
containing tabular grain emulsions.
[0132] Following is a description of the terms "dye image-forming compound" and "photographically
useful group-releasing compound", sometimes referred to simply as "PUG-releasing compound",
as used herein.
[0133] A dye image-forming compound is typically a coupler compound, a dye redox releaser
compound, a dye developer compound, an oxichromic developer compound, or a bleachable
dye or dye precursor compound. Dye redox releaser, dye developer, and oxichromic developer
compounds useful in color photographic elements that can be employed in image transfer
processes are described in
The Theory of the Photographic Process, 4th edition, T.H. James, editor, Macmillan, New York, 1977, Chapter 12, Section
V, and in Section XXIII of
Research Disclosure, December 1989, Item 308119, published by Kenneth Mason Publications, Ltd., Dudley
Annex, 12a North Street, Emsworth, Hampshire, PO1O 7DQ, United Kingdom. Dye compounds
useful in color photographic elements employed in dye bleach processes are described
in Chapter 12, Section IV, of
The Theory of the Photographic Process, 4th edition.
[0134] Preferred dye image-forming compounds are coupler compounds that react with oxidized
color developing agents to form colored products or dyes. A coupler compound contains
a coupler moiety COUP, that is combined with the oxidized developer species in the
coupling reaction to form the dye structure. A coupler compound can additionally contain
a group, called a coupling-off group, that is attached to the coupler moiety by a
bond that is cleaved upon reaction of the coupler compound with oxidized color developing
agent. Coupling-off groups can be halogen, such as chloro, bromo, fluoro, and iodo,
or organic radicals that are attached to the coupler moieties by atoms such as oxygen,
sulfur, nitrogen, phosphorus, and the like.
[0135] A PUG-releasing compound is a compound that contains a photographically useful group
and is capable of reacting with an oxidized developing agent to release said group.
Such a PUG-releasing compound comprises a carrier moiety and a leaving group, that
are linked by a bond that is cleaved upon reaction with oxidized developing agent.
The leaving group contains the PUG, that can be present either as a preformed species,
or as a blocked or precursor species that undergoes further reaction after cleavage
of the leaving group from the carrier to produce the PUG. The reaction of an oxidized
developing agent with a PUG-releasing compound can produce either colored or colorless
products.
[0136] Carrier moieties (CAR) include hydroquinones, catechols, aminophenols, sulfonamidophenols,
sulfonamidonaphthols, hydrazides, and the like that undergo cross-oxidation by oxidized
developing agents. A preferred carrier moiety in a PUG-releasing compound is a coupler
moiety COUP, that can combine with an oxidized color developer in the cleavage reaction
to form a colored species, or dye. When the carrier moiety is a COUP, the leaving
group is referred to as a coupling-off group. As described previously for leaving
groups in general, the coupling-off group contains the PUG, either as a preformed
species or as a blocked or precursor species. The coupler moiety can be ballasted
or unballasted. It can be monomeric, or it can be part of a dimeric, oligomeric or
polymeric coupler, in which case more than one group containing PUG can be contained
in the coupler, or it can form part of a bis compound in which the PUG forms part
of a link between two coupler moieties.
[0137] The PUG can be any group that is typically made available in a photographic element
in an imagewise fashion. The PUG can be a photographic reagent or a photographic dye.
A photographic reagent, that upon release further reacts with components in the photographic
element as described herein, is a moiety such as a development inhibitor, a development
accelerator, a bleach inhibitor, a bleach accelerator, an electron transfer agent,
a coupler (for example, a competing coupler, a dye-forming coupler, or a development
inhibitor releasing coupler, a dye precursor, a dye, a developing agent (for example,
a competing developing agent, a dye-forming developing agent, or a silver halide developing
agent), a silver complexing agent, a fixing agent, an image toner, a stabilizer, a
hardener, a tanning agent, a fogging agent, an ultraviolet radiation absorber, an
antifoggant, a nucleator, a chemical or spectral sensitizer, or a desensitizer.
[0138] The PUG can be present in the coupling-off group as a preformed species or it can
be present in a blocked form or as a precursor. The PUG can be, for example, a preformed
development inhibitor, or the development inhibiting function can be blocked by being
the point of attachment to the carbonyl group bonded to PUG in the coupling-off group.
Other examples are a preformed dye, a dye that is blocked to shift its absorption,
and a leuco dye.
[0139] A PUG-releasing compound can be described by the formula CAR-(TIME)
n-PUG, wherein (TIME) is a linking or timing group, n is 0, 1, or 2, and CAR is a carrier
moiety from which is released imagewise a PUG (when n is 0) or a PUG precursor (TIME)
1-PUG or (TIME)
2-PUG (when n is 1 or 2) upon reacting with oxidized developing agent. Subsequent reaction
of (TIME)
1-PUG or (TIME)
2-PUG produces PUG.
[0140] Linking groups (TIME), when present, are groups such as esters, carbamates, and the
like that undergo base-catalyzed cleavage, including intramolecular nucleophilic displacement,
thereby releasing PUG. Where n is 2, the (TIME) groups can be the same or different.
Suitable linking groups, that are also known as timing groups, are shown in US-A-Nos.
5,151,343; 5,051,345; 5,006,448; 4,409,323; 4,248,962; 4,847,185; 4,857,440; 4,857,447;
4,861,701; 5,021,322; 5,026,628, and 5,021,555. Especially useful linking groups are
p-hydroxphenylmethylene moieties, as illustrated in the previously mentioned US-A-Nos.
4,409,323; 5,151,343 and 5,006,448, and o-hydroxyphenyl substituted carbamate groups,
disclosed in US-A-Nos. 5,151,343 and 5,021,555, that undergo intramolecular cyclization
in releasing PUG.
[0141] When TIME is joined to a COUP, it can be bonded at any of the positions from which
groups are released from couplers by reaction with oxidized color developing agent.
Preferably, TIME is attached at the coupling position of the coupler moiety so that,
upon reaction of the coupler with oxidized color developing agent, TIME, with attached
groups, will be released from COUP.
[0142] TIME can also be in a non-coupling position of the coupler moiety from which it can
be displaced as a result of reaction of the coupler with oxidized color developing
agent. In the case where TIME is in a non-coupling position of COUP, other groups
can be in the coupling position, including conventional coupling off groups. Also,
the same or different inhibitor moieties from those described in this invention can
be used. Alternatively, COUP can have TIME and PUG in each of a coupling position
and a non-coupling position. Accordingly, compounds useful in this invention can release
more than one mol of PUG per mol of coupler.
[0143] TIME can be any organic group that will serve to connect CAR to the PUG moiety and
which, after cleavage from CAR, will in turn be cleaved from the PUG moiety. This
cleavage is preferably by an intramolecular nucleophilic displacement reaction of
the type described in, for example, US-A-4,248,962, or by electron transfer along
a conjugated chain as described in, for example, US-A-4,409,323.
[0144] As used herein, the term "intramolecular nucleophilic displacement reaction" refers
to a reaction in which a nucleophilic center of a compound reacts directly, or indirectly
through an intervening molecule, at another site on the compound, that is an electrophilic
center, to effect displacement of a group or atom attached to the electrophilic center.
Such compounds have both a nucleophilic group and an electrophilic group spatially
related by the configuration of the molecule to promote reactive proximity. Preferably,
the nucleophilic group and the electrophilic group are located in the compound so
that a cyclic organic ring, or a transient cyclic organic ring, can be easily formed
by an intramolecular reaction involving the nucleophilic center and the electrophilic
center.
[0145] Useful timing groups are represented by the structure: (̵Nu―LINK)̵E wherein:
Nu is a nucleophilic group attached to a position on CAR from which it will be
displaced upon reaction of CAR with oxidized developing agent;
E is an electrophilic group attached to an inhibitor moiety as described and is
displaceable therefrom by Nu after Nu is displaced from CAR; and
LINK is a linking group for spatially relating Nu and E, upon displacement of Nu
from CAR, to undergo an intramolecular nucleophilic displacement reaction with the
formation of a 3- to 7-membered ring
and thereby release the PUG moiety.
[0146] A nucleophilic group (Nu) is defined herein as a group of atoms one of which is electron
rich. Such an atom is referred to as a nucleophilic center. An electrophilic group
(E) is defined herein as a group of atoms, one of which is electron deficient. Such
an atom is referred to as an electrophilic center.
[0147] Thus, in PUG-releasing compounds as described herein, the timing group can contain
a nucleophilic group and an electrophilic group, which groups are spatially related
with respect to one another by a linking group so that, upon release from CAR, the
nucleophilic center and the electrophilic center will react to effect displacement
of the PUG moiety from the timing group. The nucleophilic center should be prevented
from reacting with the electrophilic center until release from the CAR moiety, and
the electrophilic center should be resistant to external attack, such as hydrolysis.
Premature reaction can be prevented by attaching the CAR moiety to the timing group
at the nucleophilic center or an atom in conjunction with a nucleophilic center, so
that cleavage of the timing group and the PUG moiety from CAR unblocks the nucleophilic
center and permits it to react with the electrophilic center, or by positioning the
nucleophilic group and the electrophilic group so that they are prevented from coming
into reactive proximity until release. The timing group can contain additional substituents,
such as additional photographically useful groups (PUGs), or precursors thereof, that
may remain attached to the timing group or be released.
[0148] It will be appreciated that, in the timing group, for an intramolecular reaction
to occur between the nucleophilic group and the electrophilic group, the groups should
be spatially related after cleavage from CAR so that they can react with one another.
Preferably, the nucleophilic group and the electrophilic group are spatially related
within the timing group so that the intramolecular nucleophilic displacement reaction
involves the formation of a 3- to 7-membered ring, most preferably a 5- or 6-membered
ring.
[0149] It will be further appreciated that for an intramolecular reaction to occur in the
aqueous alkaline environment encountered during photographic processing, the thermodynamics
should be such and the groups be so selected that an overall free energy decrease
results upon ring closure, forming the bond between the nucleophilic group and the
electrophilic group, and breaking the bond between the electrophilic group and the
PUG. Not all possible combinations of nucleophilic group, linking group, and electrophilic
group will yield a thermodynamic relationship favorable to breaking of the bond between
the electrophilic group and the PUG moiety. However, it is within the skill of the
art to select appropriate combinations taking the above energy relationships into
account.
[0150] Representative Nu groups contain electron rich oxygen, sulfur and nitrogen atoms.
Representative E groups contain electron deficient carbonyl, thiocarbonyl, phosphonyl
and thiophosphonyl moieties. Other useful Nu and E groups will be apparent to those
skilled in the art.
[0151] The linking group can be an acyclic group such as alkylene, for example, methylene,
ethylene or propylene, or a cyclic group such as an aromatic group, such as phenylene
or naphthylene, or a heterocyclic group, such as furan, thophene, pyridine, quinoline
or benzoxazine. Preferably, LINK is alkylene or arylene. The groups Nu and E are attached
to LINK to provide, upon release of Nu from CAR, a favorable spatial relationship
for nucleophilic attack of the nucleophilic center in Nu on the electrophilic center
in E. When LINK is a cyclic group, Nu and E can be attached to the same or adjacent
rings. Aromatic groups in which Nu and E are attached to adjacent ring positions are
particularly preferred LINK groups.
[0152] TIME can be unsubstituted or substituted. The substituents can be those that will
modify the rate of reaction, diffusion, or displacement, such as halogen, including
fluoro, chloro, bromo, or iodo, nitro, alkyl of 1 to 20 carbon atoms, acyl, such as
carboxy, carboxyalkyl, alkoxycarbonyl, alkoxycarbonamido, sulfoalkyl, alkanesulfonamido,
and alkylsulfonyl, solubilizing groups, ballast groups and the like, or they can be
substituents that are separately useful in the photographic element, such as a stabilizer,
an antifoggant, a dye (such as a filter dye or a solubilized masking dye) and the
like. For example, solubilizing groups will increase the rate of diffusion; ballast
groups will decrease the rate of diffusion; electron withdrawing groups will decrease
the rate of displacement of the PUG.
[0153] As used herein, the term "electron transfer down a conjugated chain" is understood
to refer to transfer of an electron along a chain of atoms in which alternate single
bonds and double bonds occur. A conjugated chain is understood to have the same meaning
as commonly used in organic chemistry. This further includes TIME groups capable of
undergoing fragmentation reactions where the number of double bonds is zero. Electron
transfer down a conjugated chain is described in, for example, US-A-4,409,323.
[0154] As previously described, more than one sequential TIME moiety can be usefully employed.
Useful TIME moieties can have a finite half-life or an extremely short half-life.
The half-life is controlled by the specific structure of the TIME moiety, and may
be chosen so as to best optimize the photographic function intended. TIME moiety half-lives
of from less than 0.001 second to over 10 minutes are known in the art. TIME moieties
having a half-life of over 0.1 second are often preferred for use in PUG-releasing
compounds that yield development inhibitor moieties, although use of TIME moieties
with shorter half-lives to produce development inhibitor moieties is known in the
art. The TIME moiety may either spontaneously liberate a PUG after being released
from CAR, or may liberate PUG only after a further reaction with another species present
in a process solution, or may liberate PUG during contact of the photographic element
with a process solution.
[0155] The dye image-forming compounds and PUG-releasing compounds can be incorporated in
photographic elements of the present invention by means and processes known in the
photographic art. A photographic element in which the dye image-forming and PUG-releasing
compounds are incorporated can be a monocolor element comprising a support and a single
silver halide emulsion layer, or it can be a multicolor, multilayer element comprising
a support and multiple silver halide emulsion layers. The above described compounds
can be incorporated in at least one of the silver halide emulsion layers and/or in
at least one other layer, such as an adjacent layer, where they are in reactive association
with the silver halide emulsion layer and are thereby able to react with the oxidized
developing agent produced by development of silver halide in the emulsion layer. Additionally,
the silver halide emulsion layers and other layers of the photographic element can
contain addenda conventionally contained in such layers.
[0156] A typical multicolor, multilayer photographic element can comprise a support having
thereon a red-sensitized silver halide emulsion unit having associated therewith a
cyan dye image-forming compound, a green-sensitized silver halide emulsion unit having
associated therewith a magenta dye image-forming compound, and a blue-sensitized silver
halide emulsion unit having associated therewith a yellow dye image-forming compound.
Each silver halide emulsion unit can be composed of one or more layers, and the various
units and layers can be arranged in different locations with respect to one another,
as known in the prior art and as illustrated by layer order formats hereinafter described.
[0157] In an element of the invention, a layer or unit affected by PUG can be controlled
by incorporating in appropriate locations in the element a layer that confines the
action of PUG to the desired layer or unit. Thus, at least one of the layers of the
photographic element can be, for example, a scavenger layer, a mordant layer, or a
barrier layer. Examples of such layers are described in, for example, US-A-Nos. 4,055,429;
4,317,892; 4,504,569; 4,865,946; and 5,006,451. The element can also contain additional
layers such as antihalation layers, filter layers and the like. It is generally preferred
to minimize the thickness of the element above the support so as to improve sharpness
and improve access of processing solutions to the components of the element. For this
reason, thicknesses of less than 30 micrometers are generally useful while thicknesses
of between 5 and 25 micrometers are preferred and thicknesses of between 7 and 20
micrometers are even more preferred. These lowered thicknesses can be enabled at manufacture
by use of surfactants and coatings aids as known in the art so as to control viscosity
and shear.
[0158] Both sharpness and ease of processing may be further improved by minimizing the quantity
of incorporated silver in the element. While any useful quantity of light sensitive
silver may be employed in the elements of this invention, total silver quantities
of between 1 and 10 grams per square meter are contemplated and total silver of less
than 7 grams per square meter are preferred. Total silver of between 1 and 5 grams
per square meter are even more preferred. Sharpness and color rendition in color images
is further improved by complete removal of silver and silver halide from the element
on processing. Since more swellable elements enable better access of components of
processing solutions to the elements of this invention, swell ratios above 1.25 are
preferred, with swell ratios of between 1.4 and 6 being more preferred and swell ratios
of between 1.7 and 3 being most preferred. The balance of total thickness,' total
silver and swell ratio most suitable for an element intended for a specific purpose
being readily derived from the image structure, color reproduction, sensitivity and
physical integrity and photographic resistance to pressure required for that purpose
as known in the art. Further, this invention may be particularly useful with a magnetic
recording layer such as those described in
Research Disclosure, Item 34390, November 1992, p. 869.
[0159] In the following discussion of suitable materials for use in the elements of this
invention, reference will be made to the previously mentioned
Research Disclosure, December 1989, Item 308119.
[0160] Suitable dispersing media for the emulsion layers and other layers of elements of
this invention are described in Section IX of
Research Disclosure, December 1989, Item 308119, and publications therein.
[0161] In addition to the compounds described herein, the elements of this invention can
include additional dye image-forming compounds, as described in Sections VII A-E and
H, and additional PUG-releasing compounds, as described in Sections VII F and G of
Research Disclosure, December 1989, Item 308119, and the publications cited therein.
[0162] The elements of this invention can contain brighteners (Section V), antifoggants
and stabilizers (Section VI), antistain agents and image dye stabilizers (Section
VII I and J), light absorbing and scattering materials (Section VIII), hardeners (Section
X), coating aids (Section XI), plasticizers and lubricants (Section XII), antistatic
agents (Section XIII), matting agents (Section XVI), and development modifiers (Section
XXI), all in
Research Disclosure, December 1989, Item 308119.
[0163] The elements of the invention can be coated on a variety of supports, as described
in Section XVII of
Research Disclosure, December 1989, Item 308119, and references cited therein. The supports employed
in this invention are flexible supports. Typical flexible supports include films of
cellulose nitrate, cellulose acetate, polyvinylacetal, polyethylene terephthalate,
polycarbonate and related resinous and polymeric materials. These supports can be
of any suitable thickness and will preferably be less than 150 micrometers thick,
more preferably between 50 and 130 micrometers thick and most preferably between 60
and 110 micrometers thick.
[0164] When the light sensitive elements of this invention are color originating or color
display materials, it is generally intended that they be supplied on spools or in
cartridge form generally as known in the art. When the element is supplied in spool
form it may be wrapped about a core and enclosed in a removable housing with an exposed
film leader as known in the art. When the element is supplied in cartridge form, the
cartridge may enclose a light sensitive photographic element in roll form and a housing
surrounding the film to form a cartridge receptacle for protecting the film from exposure
and an opening for withdrawing the film from the cartridge receptacle. It is further
intended that such materials be supplied in a length that results in the element being
forced to assume a radius of curvature of less than 12,000 micrometers, and preferably
a radius of curvature less than 9,000 or 6,500 or even 6,000 micrometers or even less.
[0165] In another embodiment, the element may be supplied on similar or even less demanding
spools and forced by a camera mechanism or the like through a constricted radius of
curvature as small as 1,400 or even 1,000 micrometers. This severe curvature may occur
in a consumer loadable camera or in a preloaded camera as known in the art. These
cameras can provide specific features as known in the art such as shutter means, film
advance means, waterproof housings, single or multiple lenses, lens selection means,
variable aperture, focus or focal length lenses, means for monitoring lighting conditions,
means for altering shutter times or lens characteristics based on lighting conditions
or user provided instructions, and means for recording use conditions directly on
the film. When the element is supplied in a preloaded camera, known also as a film
with camera unit, the camera may comprise a lens, a shutter, the element in roll form,
means for holding the element in roll form prior to exposure, means for mounting a
portion of the element for exposure through the lens, means for receiving portions
of the element from the mounting means, and a housing for mounting the lens and shutter
and for restricting light access to the film to that entering the camera through the
lens.
[0166] The elements of this invention can be exposed to actinic radiation, typically in
the visible region of the spectrum as described in greater detail hereinafter, to
form a latent image and then processed to form a visible dye image, as described in
Sections XVIII and XIX of
Research Disclosure, December 1989, Item 308119.
Mixture of Isomeric Didodecylhydroquinones
[0168]

Of course, the color photographic elements useful in this invention can contain
any of the optional additional layers and components known to be useful in color photographic
elements in general, such as, for example, subbing layers, overcoat layers, surfactants
and plasticizers, some of which are discussed in detail hereinbefore. They can be
coated onto appropriate supports using any suitable technique, including, for example,
those described in
Research Disclosure, December 1989, Item 308117, Section XV Coating and Drying Procedures, published
by Industrial Opportunities Ltd., Homewell Havant, Hampshire, PO9 1EF, U.K..
[0169] The photographic elements containing radiation sensitive {100} tabular grain emulsion
layers that are processed according to this invention can be imagewise-exposed with
various forms of energy that encompass the ultraviolet and visible (for example, actinic)
and infrared regions of the electromagnetic spectrum, as well as electron-beam and
beta radiation, gamma ray, X-ray, alpha particle, neutron radiation and other forms
of corpuscular and wave-like radiant energy in either noncoherent (random phase) forms
or coherent (in phase) forms as produced by lasers. Exposures can be monochromatic,
orthochromatic or panchromatic. Imagewise exposures at ambient, elevated or reduced
temperatures and/or pressures, including high-or low-intensity exposures, continuous
or intermittent exposures, exposure times ranging from minutes to relatively short
durations in the millisecond to microsecond range and solarizing exposures, can be
employed within the useful response ranges determined by conventional sensitometric
techniques, as illustrated by T. H. James,
The Theory of the Photographic Process, 4th Ed., Macmillan, 1977, Chapters 4, 6, 17, 18 and 23.
[0170] The following examples are intended to illustrate, without limiting, this invention.
Examples
[0171] The invention can be better appreciated by reference to the following examples. Throughout
the examples the acronym APMT is employed to designate 1-(3-acetamidophenyl)-5-mercaptotetrazole.
The term "low methionine gelatin" is employed, except as otherwise indicated, to designate
gelatin that has been treated with an oxidizing agent to reduce its methionine content
to less than 30 micromoles per gram. The acronym DW is employed to indicate distilled
water. The acronym mppm is employed to indicate molar parts per million.
Emulsion Preparation Example 1
[0172] This example demonstrates the preparation of an ultrathin tabular grain silver iodochloride
emulsion satisfying the requirements of this invention.
[0173] A 2030 ml solution containing 1.75% by weight low methionine gelatin, 0.011 molar
sodium chloride and 1.48 x 10
-4 molar potassium iodide was provided in a stirred reaction vessel. The contents of
the reaction vessel were maintained at 40
oC and the pCl was 1.95.
[0174] While this solution was vigorously stirred, 30 ml of 1.0 molar silver nitrate solution
and 30 ml of a 0.99 molar sodium chloride and 0.01 molar potassium iodide solution
were added simultaneously at a rate of 30 ml/min each. This achieved grain nucleation
to form crystals with an initial iodide concentration of 2 mol %, based on total silver.
[0175] The mixture was then held 10 minutes with the temperature remaining at 40
oC. Following the hold, a 1.0 molar silver nitrate solution and a 1.0 molar NaCl solution
were then added simultaneously at 2 ml/min for 40 minutes with the pCl being maintained
at 1.95.
[0176] The resulting emulsion was a tabular grain silver iodochloride emulsion containing
0.5 mol % iodide, based on silver. Fifty percent of total grain projected area was
provided by tabular grains having {100} major faces having an average ECD of 0.84
mm and an average thickness of 0.037 mm, selected on the basis of an aspect ratio
rank ordering of all {100} tabular grains having a thickness of less than 0.3 mm and
a major face edge length ratio of less than 10. The selected tabular grain population
had an average aspect ratio (ECD/t) of 23 and an average tabularity (ECD/t
2) of 657. The ratio of major face edge lengths of the selected tabular grains was
1.4. Seventy two percent of total grain projected area was made up of tabular grains
having {100} major faces and aspect ratios of at least 7.5. These tabular grains had
a mean ECD of 0.75 mm, a mean thickness of 0.045 mm, a mean aspect ratio of 18.6 and
a mean tabularity of 488.
[0177] A representative sample of the grains of the emulsion is shown in Figure 1.
Emulsion Preparation Example 2 (Comparative)
[0178] This emulsion demonstrates the importance of iodide in the precipitation of the initial
grain population (nucleation).
[0179] This emulsion was precipitated identically to that of Example 1, except no iodide
was intentionally added.
[0180] The resulting emulsion consisted primarily of cubes and very low aspect ratio rectangular
grains ranging in size from about 0.1 to 0.5 mm in edge length. A small number of
large rods and high aspect ratio {100} tabular grains were present, but did not constitute
a useful quantity of the grain population.
[0181] A representative sample of the grains of this emulsion is shown in Figure 2.
Emulsion Preparation Example 3
[0182] This example demonstrates an emulsion according to the invention in which 90% of
the total grain projected area is comprised of tabular grains with {100} major faces
and aspect ratios of greater than 7.5.
[0183] A 2030 ml solution containing 3.52% by weight low methionine gelatin, 0.0056 molar
sodium chloride and 1.48 x 10
-4 molar potassium iodide was provided in a stirred reaction vessel. The contents of
the reaction vessel were maintained at 40
oC and the pCl was 2.25.
[0184] While this solution was vigorously stirred, 30 ml of 2.0 molar silver nitrate solution
and 30 ml of a 1.99 molar sodium chloride and 0.01 molar potassium iodide solution
were added simultaneously at a rate of 60 ml/min each. This achieved grain nucleation
to form crystals with an initial iodide concentration of 1 mol %, based on total silver.
[0185] The mixture was then held 10 minutes with the temperature remaining at 40
oC. Following the hold, a 0.5 molar silver nitrate solution and a 0.5 molar NaCl solution
were then added simultaneously at 8 ml/min for 40 minutes with the pCl being maintained
at 2.25. The 0.5 molar AgNO
3 solution and the 0.5 molar NaCl solution were then added simultaneously with a ramped
linearly increasing flow from 8 ml per minute to 16 ml per minute over 130 minutes
with the pCl maintained at 2.25.
[0186] The resulting emulsion was a tabular grain silver iodochloride emulsion containing
0.06 mol % iodide, based on silver. Fifty percent of total grain projected area was
provided by tabular grains having {100} major faces having an average ECD of 1.86
mm and an average thickness of 0.082 mm, selected on the basis of an aspect ratio
rank ordering of all {100} tabular grains having a thickness of less than 0.3 mm and
a major face edge length ratio of less than 10. The selected tabular grain population
had an average aspect ratio (ECD/t) of 24 and an average tabularity (ECD/t
2) of 314. The ratio of major face edge lengths of the selected tabular grains was
1.2. Ninety three percent of total grain projected area was made up of tabular grains
having {100} major faces and aspect ratios of at least 7.5. These tabular grains had
a mean ECD of 1.47 mm, a mean thickness of 0.086 mm, a mean aspect ratio of 17.5 and
a mean tabularity of 222.
Emulsion Preparation Example 4
[0187] This example demonstrates an emulsion prepared similarly as the emulsion of Example
3, but an initial 0.08 mol % silver iodide and a final 0.04% silver iodide.
[0188] A 2030 ml solution containing 3.52% by weight low methionine gelatin, 0.0056 molar
sodium chloride and 3.00 x 10
-5 molar potassium iodide was provided in a stirred reaction vessel. The contents of
the reaction vessel were maintained at 40
oC and the pCl was 2.25.
[0189] While this solution was vigorously stirred, 30 ml of 5.0 molar silver nitrate solution
and 30 ml of a 4.998 molar sodium chloride and 0.002 molar potassium iodide solution
were added simultaneously at a rate of 60 ml/min each. This achieved grain nucleation
to form crystals with an initial iodide concentration of 0.08 mol %, based on total
silver.
[0190] The mixture was then held 10 minutes with the temperature remaining at 40
oC. Following the hold, a 0.5 molar silver nitrate solution and a 0.5 molar sodium
chloride solution were then added simultaneously at 8 ml/min for 40 minutes with the
pCl being maintained at 2.95.
[0191] The resulting emulsion was a tabular grain silver iodochloride emulsion containing
0.04 mol % iodide, based on silver. Fifty percent of the total grain projected area
was provided by tabular grains having {100} major faces having an average ECD of 0.67
mm and an average thickness of 0.035 mm, selected on the basis of an aspect ratio
rank ordering of all {100} tabular grains having a thickness of less than 0.3 mm and
a major face edge length ratio of less than 10. The selected tabular grain population
had an average aspect ratio (ECD/t) of 20 and an average tabularity (ECD/t
2) of 651. The ratio of major face edge lengths of the selected tabular grains was
1.9. Fifty two percent of total grain projected area was made up of tabular grains
having {100} major faces and aspect ratios of at least 7.5. These tabular grains had
a mean ECD of 0.63 mm, a mean thickness of 0.036 mm, a mean aspect ratio of 18.5 and
a mean tabularity of 595.
Emulsion Preparation Example 5
[0192] This example demonstrates an emulsion in which the initial grain population contained
6.0 mol % iodide and the final emulsion contained 1.6% iodide.
[0193] A 2030 ml solution containing 3.52% by weight low methionine gelatin, 0.0056 molar
sodium chloride and 3.00 x 10
-5 molar potassium iodide was provided in a stirred reaction vessel. The contents of
the reaction vessel were maintained at 40
oC and the pCl was 2.25.
[0194] While this solution was vigorously stirred, 30 ml of 1.0 molar silver nitrate solution
and 30 ml of a 0.97 molar sodium chloride and 0.03 molar potassium iodide solution
were added simultaneously at a rate of 60 ml/min each. This achieved grain nucleation
to form crystals with an initial iodide concentration of 6.0 mol %, based on total
silver.
[0195] The mixture was then held 10 minutes with the temperature remaining at 40
oC. Following the hold, a 1.00 molar silver nitrate solution and a 1.00 molar sodium
chloride solution were then added simultaneously at 2 ml/min for 40 minutes with the
pCl being maintained at 2.25.
[0196] The resulting emulsion was a tabular grain silver iodochloride emulsion containing
1.6 mol % iodide, based on silver. Fifty percent of total grain projected area was
provided by tabular grains having {100} major faces having an average ECD of 0.57
mm and an average thickness of 0.036 mm, selected on the basis of an aspect ratio
rank ordering of all {100} tabular grains having a thickness of less than 0.3 mm and
a major face edge length ratio of less than 10. The selected tabular grain population
had an average aspect ratio (ECD/t) of 16.2 and an average tabularity (ECD/t
2) of 494. The ratio of major face edge lengths of the selected tabular grains was
1.9. Sixty two percent of total grain projected area was made up of tabular grains
having {100} major faces and aspect ratios of at least 7.5. These tabular grains had
a mean ECD of 0.55 mm, a mean thickness of 0.041 mm, a mean aspect ratio of 14.5 and
a mean tabularity of 421.
Emulsion Preparation Example 6
[0197] This example demonstrates an ultrathin high aspect ratio {100} tabular grain emulsion
in which 2 mol % iodide is present in the initial population and additional iodide
is added during growth to make the final iodide level 5 mol
[0198] A 2030 ml solution containing 1.75% by weight low methionine gelatin, 0.0056 molar
sodium chloride and 1.48 x 10
-4 molar potassium iodide was provided in a stirred reaction vessel. The contents of
the reaction vessel were maintained at 40
oC and the pCl was 2.2.
[0199] While this solution was vigorously stirred, 30 ml of 1.0 molar silver nitrate solution
and 30 ml of a 0.99 molar sodium chloride and 0.01 molar potassium iodide solution
were added simultaneously at a rate of 90 ml/min each. This achieved grain nucleation
to form crystals with an initial iodide concentration of 2 mol %, based on total silver.
[0200] The mixture was then held 10 minutes with the temperature remaining at 40
oC. Following the hold, a 1.00 molar silver nitrate solution and a 1.00 molar sodium
chloride solution were then added simultaneously at 8 ml/min while a 3.75 X 10
-3 molar potassium iodide was simultaneously added at 14.6 ml/min for 10 minutes with
the pCl being maintained at 2.35.
[0201] The resulting emulsion was a tabular grain silver iodochloride emulsion containing
5 mol % iodide, based on silver. Fifty percent of total grain projected area was provided
by tabular grains having {100} major faces having an average ECD of 0.58 mmolar and
an average thickness of 0.030 mmolar, selected on the basis of an aspect ratio rank
ordering of all {100} tabular grains having a thickness of less than 0.3 mm and a
major face edge length ratio less than 10. The selected tabular grain population had
an average aspect ratio (ECD/t) of 20.6 and an average tabularity (ECD/t
2) of 803. The ratio of major face edge lengths of the selected tabular grains was
2. Eighty seven percent of total grain projected area was made up of tabular grains
having {100} major faces and aspect ratios of at least 7.5. These tabular grains had
a mean ECD of 0.54 mm, a mean thickness of 0.033 mmolar, a mean aspect ratio of 17.9
and a mean tabularity of 803.
Emulsion Preparation Example 7
[0202] This example demonstrates a high aspect ratio (100) tabular emulsion where 1 mol
% silver iodide is present in the initial grain population and 50 mol % silver bromide
is added during growth to make the final emulsion 0.3 mol % silver iodide, 36 mol
% silver bromide and 63.7 mol % silver chloride.
[0203] A 2030 ml solution containing 3.52% by weight low methionine gelatin, 0.0056 molar
sodium chloride and 1.48 x 10
-4 molar potassium iodide was provided in a stirred reaction vessel. The contents of
the reaction vessel were maintained at 40
oC and the pCl was 2.25.
[0204] While this solution was vigorously stirred, 30 ml of 1.0 molar silver nitrate solution
and 30 ml of a 0.99 molar sodium chloride and 0.01 molar potassium iodide solution
were added simultaneously at a rate of 60 ml/min each. This achieved grain nucleation.
[0205] The mixture was then held 10 minutes with the temperature remaining at 40
oC. Following the hold, a 0.5 molar silver nitrate solution and a 0.25 molar sodium
chloride and 0.25 molar sodium bromide solution were then added simultaneously at
8 ml/min for 40 minutes with the pCl being maintained at 2.60 to form crystals with
an initial iodide concentration of 2 mol %, based on total silver.
[0206] The resulting emulsion was a tabular grain silver iodobromochloride emulsion containing
0.27 mol % iodide and 36 mol % bromide, based on silver, the remaining halide being
chloride. Fifty percent of total grain projected area was provided by tabular grains
having {100} major faces having an average ECD of 0.4 mm and an average thickness
of 0.032 mm, selected on the basis of an aspect ratio rank ordering of all {100} tabular
grains having a thickness of less than 0.3 mm and a major face edge length ratio of
less than 10. The selected tabular grain population had an average aspect ratio (ECD/t)
of 12.8 and an average tabularity (ECD/t
2) of 432. The ratio of major face edge lengths of the selected tabular grains was
1.9. Seventy one percent of total grain projected area was made up of tabular grains
having {100} major faces and aspect ratios of at least 7.5. These tabular grains had
a mean ECD of 0.38 mm, a mean thickness of 0.034 mm, a mean aspect ratio of 11.3 and
a mean tabularity of 363.
Emulsion preparation Example 8
[0207] This example demonstrates the preparation of an emulsion satisfying the requirements
of the invention employing phthalated gelatin as a peptizer.
[0208] To a stirred reaction vessel containing a 310 ml solution that is 1.0 percent by
weight phthalated gelatin, 0.0063 molar sodium chloride and 3.1 X 10
-4 molar KI at 40
oC, 6.0 ml of a 0.1 molar silver nitrate aqueous solution and 6.0 ml of a 0.11 molar
sodium chloride solution were each added concurrently at a rate of 6 ml/min.
[0209] The mixture was then held 10 minutes with the temperature remaining at 40
oC. Following the hold, the silver and salt solutions were added simultaneously with
a linearly accelerated flow from 3.0 ml/min to 9.0 ml/min over 15 minutes with the
pCl of the mixture being maintained at 2.7.
[0210] The resulting emulsion was a high aspect ratio tabular grain silver iodochloride
emulsion. Fifty percent of total grain projected area was provided by tabular grains
having {100} major faces having an average ECD of 0.37 mm and an average thickness
of 0.037 mm, selected on the basis of an aspect ratio rank ordering of all {100} tabular
grains having a thickness of less than 0.3 mm and a major face edge length ratio of
less than 10. The selected tabular grain population had an average aspect ratio (ECD/t)
of 10 and an average tabularity (ECD/t
2) of 330. Seventy percent of total grain projected area was made up of tabular grains
having {100} major faces and aspect ratios of at least 7.5. These tabular grains had
a mean ECD of 0.3 mm, a mean thickness of 0.04 mm, and a mean tabularity of 210.
[0211] Electron diffraction examination of the square and rectangular surfaces of the tabular
grains confirmed major face {100} crystallographic orientation.
Emulsion Preparation Example 9
[0212] This example demonstrates the preparation of an emulsion satisfying the requirements
of the invention employing an unmodified bone gelatin as a peptizer.
[0213] To a stirred reaction vessel containing a 2910 ml solution that is 0.69 percent by
weight bone gelatin, 0.0056 molar sodium chloride, 1.86 x 10
-4 molar KI and at 55
oC and pH 6.5, 60 ml of a 4.0 molar silver nitrate solution and 60.0 ml of a 4.0 molar
silver chloride solution were each added concurrently at a rate of 120 ml/min.
[0214] The mixture was then held for 5 minutes during which a 5000 ml solution that is 16.6
g/liter of low methionine gelatin was added and the pH was adjusted to 6.5 and the
pCl to 2.25. Following the hold, the silver and salt solutions were added simultaneously
with a linearly accelerated flow from 10 ml/min to 25.8 ml/min over 63 minutes with
the pCl of the mixture being maintained at 2.25.
[0215] The resulting emulsion was a high aspect ratio tabular grain silver iodochloride
emulsion containing 0.01 mol % iodide. About 65% of the total projected grain area
was provided by tabular grains having an average diameter of 1.5 mm and an average
thickness of 0.18 mm.
Emulsion Preparation Example 10
High-Aspect-Ratio High-Chloride {100} Tabular Grain Emulsion
Example 10A
[0216] A stirred reaction vessel containing 400 ml of a solution that was 0.5% in bone gelatin,
6 mmolar in 3-amino-1H-1,2,4-triazole, 0.040 molar in NaCl, and 0.20 molar in sodium
acetate was adjusted to pH 6.1 at 55
oC. To this solution at 55
oC were added simultaneously 5.0 ml of 4 molar AgNO
3 and 5.0 ml of 4 molar NaCl at a rate of 5 ml/min each.
[0217] The temperature of the mixture was then increased to 75
oC at a constant rate requiring 12 min and then held at this temperature for 5 min.
The pH was adjusted to 6.2 and held to within ±0.1 of this value, and the flow of
the AgNO
3 solution was resumed at 5 ml/min until 0.8 mol of Ag had been added. The flow of
the NaCl solution was,also resumed at a rate needed to maintain a constant pAg of
6.64.
[0218] The resulting AgCl emulsion consisted of tabular grains having {100} major faces
that made up 65% of the projected area of the total grain population. This tabular
grain population had a mean equivalent circular diameter of 1.95 mm and a mean thickness
of 0.165 mm. The average aspect ratio and tabularity were 11.8 and 71.7, respectively.
Example 10B
[0219] This emulsion was prepared similar to that of Example 10A except that the precipitation
was stopped when 0.4 mol of Ag had been added.
[0220] The resulting emulsion consisted of tabular grain having {100} major faces that made
up 65% of the projected area of the total grain population. This tabular grain population
had a mean equivalent circular diameter of 1.28 mm and a mean thickness of 0.130 mm.
The average aspect ratio and tabularity were 9.8 and 75.7, respectively.
Emulsion Preparation Example 11
pH = 6.1 Nucleation, pH @ 3.6 Growth
[0221] This example was prepared similar to that of Example 10B except that the pH of the
reaction vessel was adjusted to 3.6 for the last 95% of the AgNO
3 addition.
[0222] The resulting emulsion consisted of {100} tabular grains making up 60% of the projected
area of the total grain population. This tabular grain population had a mean equivalent
circular diameter of 1.39 mm, and a mean thickness of 0.180 mm. The average aspect
ratio and tabularity were 7.7 and 43.0, respectively.
Emulsion Preparation Example 12
High-Aspect-Ratio AgBrCl (10% Br) {100} Tabular-Grain Emulsion
[0223] This emulsion was prepared similar to that of Example 10B except that the salt solution
was 3.6 molar in NaCl and 0.4 molar in NaBr.
[0224] The resulting AgBrCl (10% Br) emulsion consisted of {100} tabular grain making up
52% of the projected area of the total grain population. This tabular grain population
had a mean equivalent circular diameter of 1.28 mm, and a mean thickness of 0.115.
The average aspect ratio and tabularity were 11.1 and 96.7, respectively.
Emulsion Preparation Example 13
3,5-Diamino-1,2,4-Triazole as {100} Tabular Grain Nucleating Agent
[0225] This emulsion was prepared similar to that of Example 10A, except that 3,5-diamino-1,2,4-triazole
(2.4 mmol) was used as the {100} tabular grain nucleating agent.
[0226] The resulting AgCl emulsion consisted of tabular grains having {100} major faces
that made up 45% of the projected area of the total grain population. This tabular
grain population had a mean equivalent circular diameter of 1.54 mm and a mean thickness
of 0.20 mm. The average aspect ratio and tabularity were 7.7 and 38.5, respectively.
Emulsion Preparation Example 14
Imidazole as {100} Tabular Grain Nucleating Agent
[0227] This emulsion was prepared similar to that of Example 10A except that imidazole (9.6
mmol) was used as the {100} tabular grain nucleating agent.
[0228] The resulting AgCl emulsion consisted of tabular grains having {100} major faces
that made up 40% of the projected area of the total grain population. This tabular
grain population had a mean equivalent circular diameter of 2.20 mm and a mean thickness
of 0.23 mm. The average aspect ratio and tabularity were 9.6 an 41.6, respectively.
Emulsion Preparation Example 15
AgCl{100} Tabular Grain Emulsion Made Without Aromatic Amine Restraining Agent
[0229] To a stirred reaction vessel containing 400 ml of a solution that was 0.25 wt.% in
bone gelatin low in methionine content (<4 mmoles per gram gelatin), 0.008 molar in
NaCl, and at pH 6.2 and 85
oC were added simultaneously a 4 molar AgNO
3 solution at 5.0 ml/min and a 4 molar NaCl solution at a rate needed to maintain a
constant pCl of 2.09. When 0.20 mol of AgNO
3 had been added, the additions were stopped for 20 sec. during which time 15 mls of
a 13.3% low methionine gelatin solution was added and the pH adjusted to 6.2. The
additions were resumed until a total of 0.4 mol of AgNO
3 had been added. The pH was held constant at 6.2 ± 0.1 during the precipitation.
[0230] The resulting AgCl emulsion consisted of tabular grains having {100} major faces
that made up 40% of the projected area of the total gain population. This tabular
grain population had a mean equivalent circular diameter of 2.18 mm and a mean thickness
of 0.199 mm. The average aspect ratio and tabularity were 11.0 and 55.0, respectively.
Preparative Photographic Element Example 16
[0231] This example illustrates the preparation of a typical multilayer multicolor color
photographic element useful in this invention. A color photographic recording material
(
Photographic Sample 1) for color development was prepared by applying the following layers in the given
sequence to a transparent support of cellulose triacetate. The quantities of silver
halide are given in g of silver per m
2. The quantities of other materials are given in g per m
2.
Layer 1 {
Antihalation Layer}: DYE-2 at 0.022 g; C-39 at 0.097 g; DYE-6 at 0.161 g; DYE-9 at 0.075 g; SOL-1 at
0.011 g; SOL-2 at 0.011 g; with 2.1 g gelatin.
Layer 2 {
Lowest Sensitivity Red-Sensitive Layer}: Red sensitive silver chloride 〈100〉-faced tabular emulsion, average equivalent
circular diameter 0.6 micrometers, average thickness 0.08 micrometers at 0.215 g;
C-1 at 0.49 g; D-20 at 0.016 g; C-42 at 0.097 g; S-2 at 0.01 g; B-1 at 0.043 g; with
gelatin at 1.01 g.
Layer 3 {
Medium Sensitivity Red-Sensitive Layer}: Red sensitive silver chloride 〈100〉-faced tabular emulsion, average equivalent
circular diameter 1.0 micrometers, average grain thickness 0.1 micrometers at 0.33
g; C-1 at 0.11 g; D-20 at 0.016 g; C-42 at 0.032 g; C-41 at 0.032 g; S-2 at 0.01 g;
with gelatin at 0.5 g.
Layer 4 {
Highest Sensitivity Red-Sensitive Layer}: Red sensitive silver chloride 〈100〉-faced tabular emulsion, average equivalent
circular diameter 1.4 micrometers, average grain thickness 0.12 micrometers at 0.75
g; C-1 at 0.022 g; D-20 at 0.005 g; C-42 at 0.022 g; C-41 at 0.011 g; S-2 at 0.01
g; with gelatin at 0.44 g.
Layer 5 {
Interlayer}: 2,5-di-t-octylhydroquinone at 0.11 g with 0.54 g of gelatin.
Layer 6 {
Lowest Sensitivity Green-Sensitive Layer}: Green sensitive silver chloride 〈100〉-faced tabular emulsion, average equivalent
circular diameter 0.6 micrometers, average grain thickness 0.08 micrometers at 0.21
g; C-2 at 0.26 g; D-1 at 0.022 g; C-40 at 0.075 g; D-16 at 0.011 g; S-2 at 0.01 g;
with gelatin at 0.76 g.
Layer 7 {
Medium Sensitivity Green-Sensitive Layer}: Green sensitive silver chloride 〈100〉-faced tabular emulsion, average equivalent
circular diameter 1.0 micrometers, average grain thickness 0.1 micrometers at 0.32
g; C-2 at 0.055 g; D-1 at 0.022 g; D-16 at 0.011 g; C-40 at 0.033 g; S-2 at 0.011
g; with gelatin at 0.43 g.
Layer 8 {
Highest Sensitivity Green-Sensitive Layer}: Green sensitive silver chloride 〈100〉-faced tabular emulsion, average equivalent
circular diameter 1.4 micrometers, average grain thickness 0.12 micrometers at 0.75
g; C-2 at 0.022 g; C-40 at 0.016 g; D-16 at 0.011 g; S-2 at 0.01 g; with gelatin at
0.43 g.
Layer 9 {
Interlayer}: DYE-7 at 0.108 g as a solid particle dye dispersion; C-39 at 0.03 g; 2,5-di-t-octylhydroquinone
at 0.11 g with 0.54 g of gelatin.
Layer 10 {
Lowest Sensitivity Blue-Sensitive Layer}: Blue sensitive silver chloride 〈100〉-faced tabular emulsion with average equivalent
circular diameter of 0.6 micrometers and average grain thickness of 0.06 micrometers
at 0.11 g; and a blue sensitive silver chloride 〈100〉-faced tabular emulsion with
average equivalent circular diameter of 1.0 micrometers and average grain thickness
of 0.10 micrometers at 0.25 g; C-27 at 0.21 g; C-29 at 0.7 g D-18 at 0.065 g; D-4
at 0.032 g; S-2 at 0.011 g; with gelatin at 0.88 g.
Layer 11 {
Highest Sensitivity Blue-Sensitive Layer}: Blue sensitive silver chloride 〈100〉-faced tabular emulsion with average equivalent
circular diameter of 2.2 micrometers and average grain thickness of 0.12 micrometers
at 0.43 g; C-3 at 0.18 g; C-27 at 0.043 g; C-29 at 0.13 g D-18 at 0.011 g; S-2 at
0.011 g; with gelatin at 0.47 g.
Layer 12 {
Protective Layer-1}: DYE-8 at 0.1 g; DYE-9 at 0.1 g; and gelatin at 0.7 g.
Layer 13 {
Protective Layer-2}: silicone lubricant at 0.04 g; tetraethylammonium perfluoro-octane sulfonate; silica
at 0.29 g; anti-matte polymethylmethacrylate beads at 0.11 g; and gelatin at 0.89
g.
[0232] This film was hardened at coating with 2% by weight to total gelatin of hardener.
The organic compounds were used as emulsions containing coupler solvents, surfactants
and stabilizers or used as solutions both as commonly practiced in the art. The coupler
solvents employed in this photographic sample included: tricresylphosphate; di-n-butyl
phthalate; N,N-di-n-ethyl lauramide; N,N-di-n-butyl lauramide; 2,4-di-t-amylphenol;
N-butyl-N-phenyl acetamide; and 1,4-cyclohexylenedimethylene bis-(2-ethoxyhexanoate).
Mixtures of compounds were employed as individual dispersions or as co-dispersions
as commonly practiced in the art.
[0233] The sample additionally comprised sodium hexametaphosphate, 1,3-butanediol, 4-hydroxy-6-methyl-1,3,3a,7-tetraazaindene
and disodium-3,5-disulfocatechol. The silver halide emulsions employed in this sample
all comprised a silver chloride core with a surrounding iodide band, and comprised
about 0.55 mol % bulk silver iodide. Other surfactants, coating aids, scavengers,
soluble absorber dyes and stabilizers as well as various iron, lead, gold, platinum,
palladium, iridium and rhodium salts were optionally added to the various emulsions
and layers of this sample as is commonly practiced in the art so as to provide good
preservability, processability, pressure resistance, anti-fungal and antibacterial
properties, antistatic properties and coatability. The total dry thickness of all
the applied layers above the support was about 16 micrometers while the thickness
from the innermost face of the sensitized layer closest to the support to the outermost
face of the sensitized layer furthest from the support was about 11.5 micrometers.
[0234] Photographic Sample 2 was a commercially available, ISO 200 rated, color negative
camera speed film that employed similar sized silver iodobromide emulsions.
Comparative Development Process Example 17
[0235] The following solutions are utilized in this and the following processing examples.

Bleach-II was 0.821 molar in glacial acetic acid; 0.372 molar in propylenediamine-tetraacetic
acid; 0.338 molar in ferric nitrate with pH adjusted to 4.6 using ammonium hydroxide.
Fix-II was 0.905 molar in ammonium thiosulfate; 0.082 molar in ammonium sulfite; 0.198
molar in sodium sulfite; 2.10 molar in ammonium thiocyanate; 0.036 molar in silver
chloride; and 0.0002 molar in sodium iodide with pH adjusted to 6.5 using ammonium
hydroxide.
Developer-III was formulated by adding to water, 34.3 g potassium carbonate, 2.32
g potassium bicarbonate, 0.81 ml of 60% 1-hydroxyethyl-1,1-diphosphonic acid, 2 g
glycine, 1.75 g N,N-diethylhydroxylamine, 7 g of potassium chloride, potassium bromide
as in Table II below, 5 g of N-(4-amino-3-methylphenyl)-N-ethyl-2-aminoethanol) as
its sulfuric acid salt, and sufficient additional water and sulfuric acid or potassium
hydroxide to make 1 liter of solution at a pH of 10.00 +/- 0.05 at 26.7 °C.
Developer-IV was formulated like Developer-I except that about 0.33 g of sodium bromide,
and about 18.1 g of N-(4-amino-3-methylphenyl)-N-ethyl-2-aminoethanol as it's sulfuric
acid salt were employed in place of the listed quantitites.
Bleach-Fix-I was 0.82 molar in ammonium thiosulfate; 0.07 molar in ammonium sulfite;
0.06 molar in sodium metabisulfite; 0.023 molar in ferric ammonium ethylene diamine
tetraacetic acid; 0.023 molar in ethylene diamine tetraacetic acid; 0.093 molar in
silver chloride and 0.0005 molar in sodium iodide.
Bleach-III was 0.028 molar in 2,6-pyridindedicarboxylic acid; 0.013 molar in Ferric
Nitrate; 0.377 molar in sodium persulfate; 0.15 molar in sodium chloride; 0.097 molar
in acetic acid with pH adjusted to 4.0 using sodium hydroxide.
Fix-III was 0.825 molar in sodium thiosulfate; 0.11 molar in sodium bisulfite; 0.036
molar in silver chloride; and 0.0002 molar in sodium iodide with pH adjusted to 6.5
using sodium hydroxide.
Use of Bleach-IV in place of Bleach-III again enabled full bleaching. Bleach-IV was
0.50 molar in sodium carbonate; 0.035 molar in 2,6-pyridindedicarboxylic acid; 1.0
molar in sodium chloride; 0.0026 molar in 1-hydroxyethyl-1,1-diphosphonic acid; 0.98
molar in hydrogen peroxide with pH adjusted to 10.0 using sodium hydroxide.
[0236] This example illustrates the criticality of bromide ion concentration in the developer
solution and the criticality of the contact time of the developer solution with the
photographic element for the practice of this invention.
[0237] Portions of Photographic Samples 1 and 2 were exposed to light through a graduated
density test object and developed according to the following process:
Developer |
(as in Table I) |
|
38 oC |
Bleach |
240˝ |
Bleach-I |
38 oC |
wash |
180˝ |
water |
35 oC |
Fix |
240˝ |
Fix-I |
38 oC |
wash |
180˝ |
water |
35 oC |
Rinse |
60˝ |
Rinse |
35 oC |
[0238] The fog density, maximum density, and by difference the usable density range produced
in each color unit, and the gamma produced in each color unit were determined. From
these, the average gamma, average usable density range and the standard deviation
in each quantity were determined for each experimental run, that is, for each experimental
combination of a film sample, developer composition and development contact time.
The coefficient of variation (COV) in gamma and in average usable density was then
determined for each run. The film sensitivity, expressed as ISO speed was also determined
for each run. These results are listed in Table I, below.
Table I
Run |
Sample |
Developer Solution ID & Time |
Bromide ion |
Sensitivity Greater Than ISO-25 |
Average Gamma |
COV Gamma |
COV Density Formation |
1 |
2 |
I 195˝ |
∼12.5 mmolar |
YES |
check |
13.3% |
13.5% |
2 |
2 |
II 45˝ |
∼0.17 mmolar |
NO |
-72% |
60.2% |
68.5% |
3 |
2 |
I 90˝ |
∼12.5 mmolar |
YES |
-25% |
11.5% |
9.3% |
4 |
2 |
I 45˝ |
∼12.5 mmolar |
NO |
-57% |
18.3% |
20.7% |
5 |
1 |
I 195˝ |
∼12.5 mmolar |
YES |
+68% |
24.6% |
14.6% |
6 |
1 |
II 45˝ |
∼0.17 mmolar |
YES |
-4% |
42.0% |
62.5% |
7 I |
1 |
I 90˝ |
∼12.5 mmolar |
YES |
+9% |
3.1% |
5.0% |
8 I |
1 |
I 45˝ |
∼12.5 mmolar |
YES |
-16% |
8.2% |
12.3% |
[0239] Run 1 illustrates the gamma, and COV in gamma and density formation available from
a current state-of-the-art commercial film employing silver iodobromide tabular shaped
emulsions when developed in its recommended developer solution for the recommended
195 seconds contact time. On reducing contact time with the same developer, as in
runs 3 and 4, the sensitivity drops dramatically as does the usable gamma. The gamma
is well below the value acceptable for later production of color prints from the camera
film. Use of the low bromide developer, typically recommended for silver chloride
cubic emulsion containing films, as in run 2, is here seen to induce large color unit
to color unite variations in both gamma and density production, that severely impairs
the color reproduction characteristics of the film. The sensitivity is also severely
degraded. In contrast, development of the high chloride tabular grain emulsion, as
in run 5, using the industry wide recommended color negative film process, results
in exceedingly high gamma production and again, large variations in gamma and density
production between color units. Use of the low bromide developer, following the teaching
of numerous publications cited earlier, as in run 6, indeed produces a highly sensitive
and rapidly available color film with reasonable average gamma. However, the variation
in both gamma and density formation between the color units is unacceptably broad.
It is only in runs 7 and 8, where a film containing high chloride tabular grain emulsions
is developed in a higher bromide developer solution for a limited period of time,
all according to the current invention, that good light sensitivity, good gamma production
and even gamma and density production between the color units is obtained.
Comparative Development Process Example 18
[0240] This example illustrates the criticality of bromide ion concentration in the developer
solution and the criticality of the contact time of the developer solution with the
photographic element for the practice of this invention. A light sensitive element
for color development (Photographic Sample 101) was prepared by applying the following
layers to a support. The quantities of silver halide are given in g of silver per
m
2. The quantities of other materials are given in g per m
2.
Layer 1 (light sensitive layer) Optimally spectrally and chemically sensitized, green
light sensitive high chloride 〈100〉 tabular grain emulsion, average equivalent circular
diameter about 1 micrometer, average grain thickness about 0.1 micrometer with a high
chloride core and a surrounding iodide containing band having an overall composition
of about AgI-0.55, Cl-99.45, at 0.32 g, image coupler C-1 at 0.43 g in gelatin.
Layer 2 (protective overcoat layer) Gelatin and surfactant with hardener added at
coating.
[0241] Portions of Sample 101 were exposed to light through a graduated density test object
and developed in Developer-III for various times followed by desilvering generally
as described in Example 17. The density and granularity of the samples after being
subjected to the various development conditions was measured and the Noise-Equivalent-Quanta
(NEQ) characteristic of the samples was determined following the procedure described
by Honjo, Journal of Imaging Technology, vol. 15, page 182-ff (1989). The NEQ summarizes
the total imaging capability of an element and takes into account granularity and
density as a function of differing exposure levels. Improvements in NEQ signify improved
signal-to-noise characteristics for an element and are taken to indicate improved
granularity at a particular density. The normalized NEQ characteristics of this emulsion
when developed for various times in a developer solution that differed only in bromide
ion concentration is listed in Table-II.
Table-II
Relative Noise-Equivalent-Quanta for a high chloride 〈100〉 tabular grain incorporated
element as a function of developer solution bromide concentration and contact time
of the element with that developer solution. |
Bromide Ion Concentration |
Contact Time |
|
30˝ |
60˝ |
90˝ |
120˝ |
180˝ |
240˝ |
0 |
100% |
78% |
55% |
34% |
6% |
1% |
0.42 mmol/liter |
105% |
79% |
60% |
38% |
15% |
4% |
0.84 mmol/liter |
107% |
81% |
* |
47% |
21% |
9% |
1.68 mmol/liter |
115% |
89% |
79% |
60% |
37% |
24% |
3.36 mmol/liter |
126% |
107% |
89% |
79% |
59% |
46% |
6.52 mmol/liter |
126% |
115% |
93% |
81% |
62% |
56% |
12.7 mmol/liter |
* |
138% |
123% |
102% |
81% |
71% |
* indicates undetermined values. |
[0242] As is readily apparent on examination of the normalized NEQ data presented in Table-II,
the best signal-to-noise characteristics may be achieved with the high chloride tabular
grain emulsions at short times of development in higher bromide ion developer solutions.
This is contrary to the teaching of associating low to no bromide ion developers with
rapid access, high speed and high image quality images from silver chloride emulsions.
Preparative Photographic Element Example and Illustrative Photographic Process Example
19
[0243] Color Negative Camera Film Photographic Sample 3 was prepared generally like Photographic
Sample 1 of Preparative Example 16 except that a) DIR compound D-20 was omitted from
layers 2, 3 and 4 and replaced by DIR compound D-32 at 0.016, 0.003, and 0.003 grams
respectively and b) DIR compound D-16 was omitted form layers 6, 7 and 8 and replaced
by DIR compound I-18 of US-A-5,250,399 at 0.020, 0.007, and 0.003 grams respectively.
An additional 8.6% gelatin was also distributed among the various light sensitive
layers and interlayers. Photographic Sample 3 thus was substantially free of development
inhibitor releasing compounds capable of releasing development inhibitors having a
free sulfur valence that binds to sulfur.
[0244] Photographic Sample 3 was exposed, processed and the results analyzed as described
in Comparative Development Process Example 17 above. Similar uniform densitometric
results were again obtained when the sample was developed according to the current
invention. At 90 seconds contact time with color developer, as in Run 7 of Example
17, sample 3 exhibited a sensitivity in excess of ISO 100. At 60 seconds contact time
with color developer, as in Run 7 of Example 17, sample 3 again exhibited excellent
sensitivity.
Illustrative Rapid Photographic Process Example 20.
[0245] Portions of Color Negative Camera Film Photographic Sample 4, like Photographic Sample
1 prepared as described in Example 16 above but differing in comprising about 5% additional
gelatin, were exposed to white light through a graduated density test object and contacted
with Developer-I at 38 °C for 90 seconds, as in Run 7 of Example 17. Ensuing contact
with Bleach-II for 20 seconds resulted in full bleaching while ensuing contact with
seasoned Fix-II for 10 seconds followed by washing and drying resulted in full fixing.
Photographic Sample 4 was fully developed and desilvered under these processing conditions
rendering it suitable for optical printing. However, under these bleaching and fixing
conditions, comparative Photographic Sample 2, developed for its designed time of
195 seconds in Developer-I, as in Run 1 of Example 17, retained excessive colored
silver deposits rendering it unsuitable for optical printing.
Illustrative Rapid Photographic Process Example 21 employing a Photographic Paper
Compatible Bleach-Fix for Desilvering.
[0246] Portions of Photographic Sample 4 were exposed to white light through a graduated
density test object and contacted with Developer-I at 38 °C for 90 seconds. Ensuing
contact with seasoned Bleach-Fix-I for 120 seconds followed by washing and drying
resulted in full desilvering. Photographic Sample 4 was fully developed and desilvered
under these processing conditions rendering it suitable for optical printing.
Illustrative Rapid and Environmentally Preferred Photographic Process Example 22 and
23.
[0247] Portions of Photographic Sample 3 were exposed to white light through a graduated
density test object and contacted with Developer-I at 38 °C for 90 seconds. Ensuing
contact with Bleach-III for 60 seconds resulted in full bleaching while ensuing contact
with seasoned Fix-III for 120 seconds followed by washing and drying resulted in full
fixing. Photographic Sample 3 was fully developed and desilvered under these processing
conditions rendering it suitable for optical printing.
Example 24
[0248] The following multilayer, multicolor photographic samples were prepared:
Photographic Sample A
Support: 0.013 cm thick clear acetate
[0249] A red light sensitive color record comprising: red sensitized silver chloride 〈100〉
faced tabular emulsion at 1.4 micrometers equivalent circular diameter, 0.14 micrometers
thick at 0.43 g/m
2, red sensitized silver chloride 〈100〉 faced tabular emulsion at 1.8 micrometers equivalent
circular diameter, 0.15 micrometers thick at 0.65 g/m
2, cyan dye-forming image coupler C-1 at 0.65 g/m
2, DIR compound D-4 at 0.065 g/m
2, DIR compound D-1 at 0.065 g/m
2, scavenger S-1 at 0.011 g/m
2, compound B-1 at 0.043 g/m
2 with 2.52 g/m
2 gelatin.
[0250] A green light sensitive color record comprising: green sensitized silver chloride
〈100〉 faced tabular emulsion at 1.2 micrometers equivalent circular diameter, 0.14
micrometers thick at 0.78 g/m
2, green sensitized silver chloride 〈100〉 faced tabular emulsion at 1.8 micrometers
equivalent circular diameter, 0.15 micrometers thick at 0.39 g/m
2, magenta dye-forming image coupler C-2 at 0.32 g/m
2, magenta dye-forming image coupler C-15 at 0.22 g/m
2, DIR compound D-4 at 0.097 g/m
2, scavenger S-1 at 0.011 g/m
2 with 2.08 g/m
2 gelatin.
[0251] A blue light sensitive color record comprising: blue sensitized silver chloride 〈100〉
faced tabular emulsion at 1.4 micrometers equivalent circular diameter, 0.14 micrometers
thick at 5.6 g/m
2, green sensitized silver chloride 〈100〉 faced tabular emulsion at 2.0 micrometers
equivalent circular diameter, 0.15 micrometers thick at 2.8 g/m
2, yellow dye-forming image coupler C-3 at 11.7 g/m
2, DIR compound D-7 at 3.5 g/m
2, scavenger S-1 at 0.12 g/m
2 with 21.0 g/m
2 gelatin.
[0252] Along with antihalation layers, interlayers, yellow filter layers and overcoat layers
as known in the art. These layers comprised 32.5 g/m
2 gelatin, DYE-1 at 0.12 g/m
2, DYE-3 at 0.12 g/m
2, DYE-9 at 1.7 g/m
2, DYE-8 at 1.7 g/m
2, DYE-7 at 1.2 g/m
2, coupler C-39 at 0.70 g/m
2, SOL-1 at 0.05 g/m
2, SOL-2 at 0.05 g/m
2, scavengers S-1 and S-2, anti-matte beads, surfactants, sequestering agents, antifoggants,
lubricants, coating aids, and so forth as known in the art. The sample was hardened
at coating. The imaging layers had a total thickness of about 11 micrometers while
the entire film had a total thickness of about 14 micrometers. Average emulsion equivalent
circular diameter and average emulsion grain thickness are reported.
[0253] The emulsions were chemically and spectrally sensitized and employed the following
spectral sensitizing dyes:
Anhydro-5,'-diphenyl-3,3'-di-(3-sulfobutyl)-9-ethyloxacarbocyanine hydroxide, sodium
salt
Anhydro-5,6-dichloro-1-ethyl-3-(3-sulfobutyl)-1'-(3-sulfopropyl)benzimidazoleoneaphtho
1,2-dithiazolocarbocyanine hydroxide, triethylammonium salt
Anhydro-5-chloro-9-ethyl-5'-phenyl-3'-(3-sulfobutyl)-3-(3-sulfopropyl) oxacarbocyanine
hydroxide, sodium salt
Anhydro-5'-chloro-5-phenyl-3,3'-di-(3-sulfopropyl) oxathiacyanine hydroxide, sodium
salt
Anhydro-4,5-benzo-3'-methyl-4'-phenyl-1-(3-sulfopropyl) naphtho 1,2-dithiazolocyanine
hydroxide
Photographic Sample B was like Photographic Sample A except that the tabular silver chloride emulsions
in the red, green and blue light sensitive layers were each replaced by equal quantities
of chemically and spectrally sensitized silver iodobromide tabular emulsions of similar
average equivalent circular diameters and similar average grain thicknesses. These
latter emulsions comprised about 4 mol % silver iodide. The red sensitized silver
iodobromide emulsions replaced the red sensitive silver chloride emulsions, the green
sensitized silver iodobromide emulsions replaced the green sensitive silver chloride
emulsions and the blue sensitized silver iodobromide emulsions replaced the blue sensitive
silver chloride emulsions.
[0254] Photographic Sample C was like Photographic Sample A except that the Development Inhibitor Releasing Couplers
enabling imagewise release of Nitrogen Ligand development inhibitors were replaced
by equal quantities of Development Inhibitor Releasing Couplers enabling imagewise
release of Sulfur Ligand development inhibitors:
a) in the red light sensitive color record, D-4 was replaced by D-7 and D-1 was replaced
by D-15;
b) in the green light sensitive color record, D-4 was replaced by D-16; and
c) in the blue light sensitive color record, D-7 was replaced by D-18.
[0255] Both Photographic Sample A and Photographic Sample B were given an exposure to light
and developed in a modified dip and dunk processor at 38
oC using fresh Developer-I, followed by bleach-fix baths A or B for times as indicated
in Table III or IV, followed by washing.
[0256] Bleach-Fix A represents the expected steady state concentrations of a bleach-fix
bath that would result from the processing of photographic sample A of this invention
having a silver laydown of about 3 g/m
2 through the bleach-fix assuming a carry-in from the developer of 64.6 ml/m
2 and a bleach-fix replenishment rate of 269 ml/m
2. Bleach-Fix B represents the expected steady state concentrations of a bleach-fix
bath that would result form the processing of comparative photographic sample B having
a silver laydown of about 3 g/m
2 through the bleach-fix assuming a carry-in from the developer of 64.6 ml/m
2 and a bleach-fix replenishment rate of 269 ml/m
2. The bleach-fix bath contents are:
|
Bleach-Fix A |
Bleach-Fix B |
Ammonium Thiosulfate |
0.8125 molar |
0.8125 molar |
Sodium Metabisulfite |
0.06 molar |
0.06 molar |
Ammonium Ferric EDTA |
0.234 molar |
0.234 molar |
EDTA |
0.023 molar |
0.023 molar |
Silver Chloride |
0.09 molar |
0 |
Silver Bromide |
0 |
0.09 molar |
Potassium Iodide |
0.0004 molar |
0.0036 molar |
pH |
6.2 |
6.2 |
The pH was adjusted with either Acetic Acid or Ammonium Hydroxide. |
Each material was bleach-fixed for varying lengths of time to determine the speed
of silver removal. Residual silver was determined at step 1 (maximum density) by X-ray
fluorescence spectroscopy. Data for residual silver as a function of time in each
bleach-fix are presented in Tables III and IV. It is apparent that while photographic
sample A of this invention is effectively desilvered in Bleach-Fix A it is not completely
desilvered in Bleach-Fix B. In addition, comparative photographic sample B is not
effectively desilvered in either bleach-fix.
Table III
D-Max Silver (g/m2) Remaining in Color Material |
Bleach-Fix Time (sec) |
Photographic Sample A |
|
Bleach-Fix A |
Bleach-Fix B |
0 |
2.76 |
2.76 |
15 |
1.40 |
1.42 |
30 |
1.05 |
1.01 |
60 |
0.28 |
0.34 |
90 |
0.09 |
0.19 |
120 |
0.08 |
0.13 |
Table IV
D-Max Silver (g/m2) Remaining in Color Material |
Bleach-Fix Time (sec) |
Photographic Sample B |
|
Bleach-Fix A |
Bleach-Fix B |
0 |
2.93 |
2.93 |
15 |
0.83 |
0.85 |
30 |
0.51 |
0.53 |
60 |
0.40 |
0.23 |
90 |
0.37 |
0.16 |
120 |
0.30 |
0.14 |
Example 25
[0257] Preparation of the following bleach-fix solutions was attempted:
|
Bleach-Fix A |
Bleach-Fix B |
Ammonium Thiosulfate |
0.8125 molar |
0.8125 molar |
Sodium Metabisulfite |
0.06 molar |
0.06 molar |
Ammonium Ferric EDTA |
0.234 molar |
0.234 molar |
EDTA |
0.023 molar |
0.023 molar |
Silver Chloride |
0.09 molar |
0 |
Silver Bromide |
0 |
0.09 molar |
Potassium Iodide |
0.0004 molar |
0.0036 molar |
pH |
6.2 |
6.2 |
The pH was adjusted with either Acetic Acid or Ammonium Hydroxide. |
|
Bleach-Fix C |
Bleach-Fix D |
Ammonium Thiosulfate |
0.8125 molar |
0.8125 molar |
Sodium Metabisulfite |
0.06 molar |
0.06 molar |
Ammonium Ferric EDTA |
0.234 molar |
0.234 molar |
EDTA |
0.023 molar |
0.023 molar |
1,2,4-Triazole-3-Thiol |
0.005 molar |
0.005 molar |
Silver Chloride |
0.09 molar |
0 |
Silver Bromide |
0 |
0.09 molar |
Potassium Iodide |
0.0004 molar |
0.0036 molar |
pH |
6.2 |
6.2 |
The pH was adjusted with either Acetic Acid or Ammonium Hydroxide. |
[0258] Bleach-Fix solutions A and B are identical to those used in Example 24 and were prepared
without incident. Bleach-Fix solutions C and D are similar to Bleach-Fix solutions
A and B except that the bleach accelerator 1,2,4-triazole-3-thiol was added. Bleach-Fix
solutions C and D could not be prepared without forming a precipitate. This indicates
that a bleach-fix solution that is replenished at a low rate cannot contain a bleach
accelerator because at the resulting high concentration of silver the solubility limit
of the complex that can form between silver and the accelerator is exceeded.
Example 26
[0259] Photographic Samples D, E and F prepared as described in Example 24 and summarized
in Table V, all of which contain the bleach accelerator releasing coupler B-1 and
the indicated tabular emulsions, were given an exposure to light and developed in
a modified dip and dunk processor at 38
oC using fresh Developer-I, followed by contact with bleach-fix bath E, for times shown
in Table VI, followed by a wash step.
|
Bleach-Fix E |
Ammonium Thiosulfate |
0.8125 molar |
Sodium Metabisulfite |
0.06 molar |
Ammonium Ferric EDTA |
0.234 molar |
EDTA |
0.023 molar |
pH |
6.2 |
The pH was adjusted with either Acetic Acid or Ammonium Hydroxide. |
[0260] Each material was bleach-fixed for varying lengths of time to determine the speed
of silver removal. Residual silver was determined by calculating the difference in
Infrared Density between the D-Max and the D-Min steps. Data for IR density differences
as a function of time for each coating is presented in Table VI. It is apparent that
while Coating F, with tabular silver chloride emulsions and benzotriazole-releasing
DI(A)R couplers, is satisfactorily desilvered in Bleach-Fix E, coatings D and E are
not.
Table V
Coating |
Ag Laydown (g/m2) |
Inhibitor Type |
Emulsion Type |
D |
2.56 |
Nitrogen |
AgIBr |
E |
2.64 |
Sulfur |
AgCl |
F |
2.69 |
Nitrogen |
AgCl |
Table VI
Silver (IR DMax - DMin) Remaining In Color Material |
Bleach-Fix Time (sec) |
Coating D |
Coating E |
Coating F |
0 |
1.75 |
1.68 |
1.71 |
15 |
0.98 |
1.35 |
1.14 |
30 |
0.62 |
0.98 |
0.74 |
60 |
0.20 |
0.37 |
0.15 |
90 |
0.12 |
0.18 |
0.02 |
120 |
0.11 |
0.17 |
0.02 |
240 |
0.07 |
0.13 |
0.02 |
Preparative Photographic Element Example 27
[0261] This example illustrates the preparation of another multilayer multicolor color photographic
element useful in the practice of this invention.
[0262] A color photographic recording material (
Photographic Sample 5) for color development was prepared by applying the following layers in the given
sequence to a transparent support of cellulose triacetate. The quantities of silver
halide are given in g of silver per m
2. The quantities of other materials are given in g/m
2.
Layer 1 {
Antihalation Layer}: DYE-1 at 0.011 g; DYE-2 at 0.022 g; C-39 at 0.097 g; DYE-6 at 0.108 g; DYE-9 at
0.075 g; SOL-1 at 0.011 g; SOL-2 at 0.011 g; with 2.1 g gelatin.
Layer 2 {
Lowest Sensitivity Red-Sensitive Layer}; Red sensitive silver chloride 〈100〉-faced tabular emulsion, average equivalent
circular diament 0.6 micrometers, average thickness 0.08 micrometers at 0.215 g; C-1
at 0.538 g; D-32 at 0.015 g; C-42 at 0.097 g; S-2 at 0.01 g; B-1 at 0.043 g; with
gelatin at 1.30 g.
Layer 3 {
Medium Sensitivity Red-Sensitive Layer}: Red sensitive silver chloride 〈100〉-faced tabular emulsion, average equivalent
circular diameter 1.0 micrometers, average grain thickness 0.1 micrometers at 0.33
g; C-1 at 0.129 g; D-32 at 0.020 g; C-42 at 0.032 g; C-41 at 0.032 g; S-2 at 0.01
g; with gelatin at 0.5 g.
Layer 4 {
Highest Sensitivity Red-Sensitive Layer}: Red sensitive silver chloride 〈100〉-faced tabular emulsion, average equivalent
circular diameter 1.4 micrometers, average grain thickness 0.12 micrometers at 0.75
g; C-1 at 0.043 g; D-32 at 0.002 g; C-42 at 0.022 g; C-41 at 0.011 g; S-2 at 0.01
g; with gelatin at 0.44 g.
Layer 5 {
Interlayer}: 2,5-di-t-octylhydroquinone at 0.11 g with 1.08 g of gelatin.
Layer 6 {
Lowest Sensitivity Green-Sensitive Layer}: Green sensitive silver chloride 〈100〉-faced tabular emulsion, average equivalent
circular diameter 0.6 micrometers, average grain thickness 0.08 micrometers at 0.16
g; C-2 at 0.28 g; D-34 at 0.019 g; C-40 at 0.097 g; S-2 at 0.01 g; with gelatin at
0.95 g.
Layer 7 {
Medium Sensitivity Green-Sensitive Layer}: Green sensitive silver chloride 〈100〉-faced tabular emulsion, average equivalent
circular diameter 0.9 micrometers at 0.32 g; C-2 at 0.055 g; D-34 at 0.006 g; C-40
at 0.027 g; S-2 at 0.011 g; with gelatin at 0.59 g.
Layer 8 {
Highest Sensitivity Green-Sensitive Layer}: Green sensitive silver chloride 〈100〉-faced tabular emulsion, average equivalent
circular diameter 1.4 micrometers, average grain thickness 0.12 micrometers at 0.70
g; C-2 at 0.065 g; C-40 at 0.027 g; D-34 at 0.002 g; S-2 at 0.01 g; with gelatin at
0.86 g.
Layer 9 {
Interlayer}: DYE-7 at 0.108 g; C-39 at 0.03 g; 2,5-di-t-octylhydroquinone at 0.11 g with 1.07
g of gelatin.
Layer 10 {
Lowest Sensitivity Blue-Sensitive Layer}: Blue sensitive silver chloride 〈100〉-faced tabular emulsion with average equivalent
circular diameter of 0.9 micrometers and average grain thickness of 0.09 micrometers
at 0.16 g; and a blue sensitive silver chloride 〈100〉-faced tabular emulsion with
average equivalent circular diameter of 1.4 micrometers and average grain thickness
of 0.14 micrometers at 0.13 g; C-27 at 0.21 g; C-29 at 0.70 g; D-4 at 0.011 g; S-2
at 0.011 g; with gelatin at 1.51 g.
Layer 11 {
Highest Sensitivity Blue-Sensitive Layer}: Blue sensitive silver chloride 〈100〉-faced tabular emulsion with average equivalent
circular diameter of 2.3 micrometers and average grain thickness of 0.18 micrometers
at 0.86 g; C-27 at 0.043 g; C-29 at 0.13 g; D-4 at 0.003 g; S-2 at 0.011 g; with gelatin
at 0.99 g.
Layer 12 {
Protective Layer-1}: DYE-8 at 0.1 g; DYE-9 at 0.1 g; and gelatin at 0.7 g.
Layer 13 {
Protective Layer-2}: Silicone libricant at 0.04 g; tetraethylammonium perfluoro-octane sulfonate; silica
at 0.29 g; anti-matte polymethylmethacrylate beads at 0.11 g; base soluble anti-matte
beads at 0.005 g; and gelatin at 0.89 g.
[0263] This film was hardened at coating with 2% by weight to total gelatin of hardner.
The organic compounds were used as emulsions containing coupler solvents, surfactants
and stabilizers or used as solutions both as commonly practiced in the art. The coupler
solvents employed in this photographic sample include: tricresylphosphate; di-n-butyl
phthalate; N,N-di-n-ethyl lauramide; N,N-di-n-butyl lauramide, 2,4-di-t-amylphenol;
N-butyl-N-phenyl acetamide; and 1,4-cyclohexylenedimethylene bis-(2-ethoxyhexanoate).
Mixtures of compounds were employed as individual dispersions or as co-dispersions
as commonly practed in the art. The sample additionlly comprised sodium hexametaphosphate,
1,3-butanediol, 4-hydroxy-6-methyl-1,3,3a,7-tetraazaindene and disodium-3,5-disulfocatechol.
The silver halide emulsions employed in this sample comprised a silver chloride core
with a surrounding iodide band, and comprised about 0.55 mol% silver iodide. Other
surfactants, coating aids, scavengers, soluble absorber dyes and stabilizers as well
as various iron, lead, gold, platinum, palladium, iridium and rhodium salts salts
were optionally added to the various emulsions and layers of this sample as is commonly
practiced in the art so as to provide good preservability, processability, pressure
resistance, anti-fungal and antibacterial properties, antistatic properties and coatability.
The total dry thickness of all the applied layers above the support was about 20 micrometers
while the thickness from the innermost face of the sensitized layer closest to the
support to the outermost face of the sensitized layer furthest from the support was
about 15 micrometers.
Comparative Development Process Example 28
[0264] This example illustrates the criticality of bromide ion concentration and developing
agent concentration as well as contact time of the developer solution with the photographic
element for the practice of this invention.
[0265] Portions of Photographic Samples 2 and 5 were exposed to light through a graduated
density test object and developed according to the following process:
Develop (as in Table VII)38 oC |
Bleach |
240˝ |
Bleach-I |
38 oC |
wash |
180˝ |
water |
35 oC |
Fix |
240˝ |
Fix-I |
38 oC |
wash |
180˝ |
water |
35 oC |
Rinse |
60˝ |
Rinse |
35 oC |
[0266] The fog density, maximum density, and by difference the useable density range produced
in each color unit, and the gamma produced in each color unit were determined. From
these, the average gamma, average useable density range and the standard deviation
in each quantity were determined for each experimental run, that is, for each experimental
combination of a film sample, developer composition and development contact time.
The coefficient of variation (COV) in gamma and in average useable density was then
determined for each run. The film sensitivity, expressed as ISO speed was also determined
for each run. These results are listed in Table VII, below.
Table VII
Run |
Sample |
Developer Solution & Time |
Bromide ion |
PPD |
Sensitivity Greater Than ISO 25 |
Average Gamma |
COV Gamma |
COV Density Formation |
9 |
2 |
I 195˝ |
∼12.5 mmolar |
∼15.5 mmolar |
YES |
check |
13.3% |
13.5% |
10 |
2 |
I 45˝ |
∼12.5 mmolar |
∼15.5 mmolar |
NO |
-57% |
18.3% |
20.7% |
11 |
2 |
IV 45˝ |
∼ 3.1 mmolar |
∼61.9 mmolar |
YES |
-57% |
22.2% |
37.7% |
12 |
2 |
IV 60˝ |
∼ 3.1 mmolar |
∼61.9 mmolar |
YES |
-38% |
20.2%. |
21.4% |
13 I |
5 |
I 90˝ |
∼12.5 mmolar |
∼15.5 mmolar |
YES |
+03% |
11.0% |
13.1% |
14 I |
5 |
IV 60˝ |
∼ 3.1 mmolar |
∼61.9 mmolar |
YES |
+16% |
11.7% |
7.9% |
15 I |
5 |
IV 45˝ |
∼ 3.1 mmolar |
∼61.9 mmolar |
YES |
-11% |
20.8% |
13.4% |
* PPD is the developing agent concentration. |
[0267] Run 9 illustrates the gamma, and COV in gamma and density formation available from
a current state-of-the-art commercial film employing silver iodobromide tabular shaped
emulsions when developed in its recommended-developer solution for the recommended
195 seconds contact time. On reducing contact time with the same developer, as in
run 10, the sensitivity drops dramatically as does the useable gamma. The gamma is
well below the value acceptable for later production of color prints from the camera
film. Use of a modified developer solution with lower bromide ion and higher developing
agent concentration enables a recovery of the sensitivity but with greatly degraded
gamma and large imbalances in density formation between the color records. Attempts
to remedy this failure with the iodobromide containing film by lowering bromide ion
concentration and increasing developing agent concentration, as in runs 11 and 12,
are seen to lead to failure. Contrarywise, development of the element including the
high chloride tabular grain emulsion, as in runs 13, 14 or 15, using either developer
formulation I or developer formulation IV for a limited time enables excellent sensitivity,
fine gamma and a desirable balance of density formation in all color records.
Preparative Photographic Element Example 29
[0268] This example illustrates the preparation of another multilayer multicolor color photographic
element useful in the invention.
[0269] A color photographic recording material (
Photographic Sample 6) for color development was prepared by applying the following layers in the given
sequence to a transparent support of cellulose triacetate. The quantities of silver
halide are given in g of silver per m
2. The quantities of other materials are given in g per m
2.
Layer 1 {
Antihalation Layer}: DYE-6 at 0.108 g; DYE-9 at 0.075 g; SOL-1 at 0.011 g; SOL-2 at 0.011 g, with 1.6
g gelatin.
Layer 2 {
Lowest Sensitivity Red-Sensitive Layer}: Red sensitive silver chloride 〈100〉-faced tabular emulsion, average equivalent
circular diameter 0.6 micrometers, average thickness 0.06 micrometers at 0.43 g; C-53
at 0.51 g; D-1 at 0.004 g; D-32 at 0.003 g; S-2 at 0.01 g; B-1 at 0.043 g; with gelatin
at 1.18 g.
Layer 3 {
Medium Sensitivity Red-Sensitive Layer}: Red sensitive silver chloride 〈100〉-faced tabular emulsion, average equivalent
circular diameter 0.9 micrometers, average grain thickness 0.09 micrometers at 0.22
g; red sensitive silver chloride 〈100〉-faced tabular emulsion, average equivalent
circular diameter 1.3 micrometers, average grain thickness 0.12 micrometers at 0.22
g; C-53 at 0.164 g; D-1 at 0.003 g; D-32 at 0.002 g; S-2 at 0.01 g; with gelatin at
0.65 g.
Layer 4 {
Highest Sensitivity Red-Sensitive Layer}: Red sensitive silver chloride 〈100〉-faced tabular emulsion, average equivalent
circular diameter 3 micrometers, average grain thickness 0.14 micrometers at 0.70
g; C-1 at 0.11 g; D-1 at 0.002 g; D-32 at 0.001 g; S-2 at 0.01 g; with gelatin at
1.08 g.
Layer 5 {
Interlayer}: 2,5-di-t-octylhydroquinone at 0.11 g with 0.75 g of gelatin.
Layer 6 {
Lowest Sensitivity Green-Sensitive Layer}: Green sensitive silver chloride 〈100〉-faced tabular emulsion, average equivalent
circular diameter 0.6 micrometers, average grain thickness 0.06 micrometers at 0.16
g; green sensitive silver chloride 〈100〉-faced tabular emulsion, average equivalent
circular diameter 0.9 micrometers, average grain thickness 0.09 micrometers at 0.16
g; C-2 at 0.11 g; C-15 at 0.47 g; D-1 at 0.011 g; D-34 at 0.003 g; S-2 at 0.01 g;
with gelatin at 0.89 g.
Layer 7 {
Medium Sensitivity Green-Sensitive Layer}: Green sensitive silver chloride 〈100〉-faced tabular emulsion, average equivalent
circular diameter 0.9 micrometers, average grain thickness 0.09 micrometers at 0.16
g; green sensitive silver chloride 〈100〉-faced tabular emulsion, average equivalent
circular diameter 1.4 micrometers, average grain thickness 0.14 micrometers at 0.22
g; C-15 at 0.15 g; D-1 at 0.003 g; D-34 at 0.002 g; S-2 at 0.011 g; with gelatin at
0.44 g.
Layer 8 {
Highest Sensitivity Green-Sensitive Layer}: Green sensitive silver chloride 〈100〉-faced tabular emulsion, average equivalent
circular diameter 2.8 micrometers, average grain thickness 0.14 micrometers at 0.70
g; C-15 at 0.14 g; D-1 at 0.002 g; D-34 at 0.001 g; S-2 at 0.01 g; with gelatin at
0.89 g.
Layer 9 {
Interlayer}: 2,5-di-t-octylhydroquinone at 0.11 g with 0.75 g of gelatin.
Layer 10 {
Lowest Sensitivity Blue-Sensitive Layer}: Blue sensitive silver chloride 〈100〉-faced tabular emulsion with average equivalent
circular diameter of 0.6 micrometers and average grain thickness of 0.06 micrometers
at 0.11 g; and a blue sensitive silver chloride 〈100〉-faced tabular emulsion with
average equivalent circular diameter of 1.0 micrometers and average grain thickness
of 0.1 micrometers at 0.11 g; C-54 at 0.86 g; D-34 at 0.002 g; D-35 at 0.032 g; S-2
at 0.011 g; with gelatin at 0.73 g.
Layer 11 {
Highest Sensitivity Blue-Sensitive Layer}: Blue sensitive silver chloride 〈100〉-faced tabular emulsion with average equivalent
circular diameter of 3 micrometers and average grain thickness of 0.18 micrometers
at 0.86 g; C-54 at 0.27 g; D-34 at 0.001 g; D-35 at 0.003 g; S-2 at 0.011 g; with
gelatin at 0.86 g.
Layer 12 {
Protective Layer-1}: DYE-8 at 0.1 g; DYE-9 at 0.1 g; and gelatin at 0.7 g.
Layer 13 {
Protective Layer-2}: silicone lubricant at 0.04 g; tetraethylammonium perfluoro-octane sulfonate; silica
at 0.29 g; anti-matte polymethylmethacrylate beads at 0.11 g; base soluble anti-matte
beads at 0.005 g; and gelatin at 0.89 g.
[0270] This film was hardened at coating with 3% by weight to total gelatin of hardner.
The organic compounds were used as emulsions containing coupler solvents, surfactants
and stabilizers or used as solutions both as commonly practiced in the art. The coupler
solvents employed in this photographic sample included: tricresylphosphate; di-n-butyl
phthalate; N,N-di-n-ethyl lauramide; N,N-di-n-butyl lauramide; di-n-butyl sebacate;
2,4-di-t-amylphenol; N-butyl-N-phenyl acetamide; and 1,4-cyclohexylenedimethylene
bis-(2-ethoxyhexanoate). Mixtures of compounds were employed as individual dispersions
or as co-dispersions as commonly practiced in the art. The sample additionally comprised
sodium hexametaphosphate, 1,3-butanediol, 4-hydroxy-6-methyl-1,3,3a,7-tetraazaindene
and disodium-3,5-disulfocatechol. The silver halide emulsions employed in this sample
comprised a silver chloride core with a surrounding iodide band, and comprised about
0.55 mol % bulk iodide. Other surfactants, coating aids, scavengers, soluble absorber
dyes and stabilizers as well as various iron, lead, gold, platinum, palladium, iridium
and rhodium salts salts were optionally added to the various emulsions and layers
of this sample as is commonly practiced in the art so as to provide good preservability,
processability, pressure resistance, anti-fungal and antibacterial properties, antistatic
properties and coatability. The total dry thickness of all the applied layers above
the support was about 17 micrometers while the thickness from the innermost face of
the sensitized layer closest to the support to the outermost face off the sensitized
layer furthest from the support was about 13 micrometers.
Comparative Development Process Example 30
[0271] This example illustrates the influence of development solution temperature and the
contact time of the developer solution with the photographic element in the practice
of this invention.
[0272] Portions of Photographic Samples 2 and 6 were exposed to light through a graduated
density test object and developed according to the following process:
Develop (as in Table VIII) |
Bleach |
240˝ |
Bleach-I |
38 oC |
wash |
180˝ |
water |
35 oC |
Fix |
240˝ |
Fix-I |
38 oC |
wash |
180˝ |
water |
35 oC |
Rinse |
60˝ |
Rinse |
35 oC |
[0273] The fog density, maximum density, and by difference the useable density range produced
in each color unit, and the gamma produced in each color unit were determined. From
these, the average gamma, average useable density range and the standard deviation
in each quantity were determined for each experimental run, that is, for each experimental
combination of a film sample, developer composition and development contact time.
The coefficient of variation (COV) in gamma and in average useable density was then
determined for each run. The film sensitivity, expressed as ISO speed was also determined
for each run. These results are listed in Table VIII, below.
Table VIII
Run |
Sample |
Developer Solution & Time |
Temperature |
Sensitivity Greater Than ISO 25 |
Average Gamma |
COV Gamma |
COV Density Formation |
16 |
2 |
I 195˝ |
. 38 oC |
YES |
check |
13.3% |
13.5% |
17 |
2 |
I 45˝ |
52 oC |
YES |
-41% |
29.8% |
30.8% |
18 I |
6 |
I 45˝ |
. 52 oC |
YES |
-4% |
2.1% |
14.9% |
[0274] Thus, while increased development solution temperature does not adequately compensate
for reduced contact time of a prior art element with a developer solution, the same
higher developer temperature can be used to compensate for reduced development time
when employed with the developer solution and elements according to the invention.