FIELD OF THE INVENTION
[0001] The present invention relates to silver halide color photographic light-sensitive
elements containing photographic couplers and, more particularly, 4-equivalent and
2-equivalent 5-pyrazolone magenta dye-forming couplers.
BACKGROUND OF THE INVENTION
[0002] It is well known that color photographic light-sensitive elements, using the subtractive
process for color reproduction, comprise silver halide emulsion layers selectively
sensitive to blue, green and red light and associated with yellow, magenta and cyan
dye-forming couplers which form (upon reaction with an oxidized primary amine type
color developing agent) the complementary color thereof. For example, an acylacetanilide
type coupler is used to form a yellow color image; a 5-pyrazolone, pyrazolotriazole,
cyanacetophenone or indazolone type coupler is used to form a magenta color image;
and a phenol type, such as a phenol or naphthol, coupler is used to form a cyan color
image.
[0003] Usually, the color photographic light-sensitive elements comprise non-diffusible
couplers incorporated independently in each of the light-sensitive layers of the material
(incorporated coupler materials). Therefore, a color photographic light-sensitive
element usually comprises 1) a blue-sensitive silver halide emulsion layer (or layers)
which contains a yellow dye-forming coupler and which is mainly sensitive to blue
light (substantially to wavelengths less than about 500 nm); 2) a green-sensitive
silver halide emulsion layer (or layers) which contains a magenta dye-forming coupler
and which is mainly sensitive to green light (substantially to wavelengths of about
500 to 600 nm); and 3) a red-sensitive silver halide emulsion layer (or layers) which
contains a cyan dye-forming coupler and which is mainly sensitive to red light (substantially
to wavelengths longer than about 590 nm).
[0004] The silver halide emulsions used in the past for such photographic elements were
the so-called mixed emulsions, that is, emulsions comprising a combination of a more
sensitive emulsion (containing coarse silver halide grains) and a less sensitive emulsion
(containing fine silver halide grains) whereby a straight density-log exposure curve
could be obtained for each blue-, green- and red-sensitive layer.
[0005] Since granularity of the dye image in color photographic elements depends mainly
upon the size of the silver halide grains employed, attempts to increase the sensitivity
of the color photographic material by increasing the size of the silver halide grains
(sensitivity of silver halide grains generally is proportional to the size of the
silver halide grains) caused a coarsening of the granularity of the dye image.
[0006] As a method for improving sensitivity, a technique has been known in which the regular
layer sequence of having respective red-sensitive, green-sensitive and blue-sensitive
silver halide emulsion layers is provided by subdividing a part or whole of each of
the emulsion layers into higher and lower sensitivity emulsion layers, each subdivided
layer containing a color coupler forming substantially the same hue as the other subdivided
layer and wherein these layers are coated adjacent to each other.
[0007] For example, GB 818,687 describes a method for increasing sensitivity in multilayer
color photographic elements in which the emulsion layer which is applied closest to
the support consists of two partial layers sensitized to the same region of the spectrum,
the lower layer consisting of a less sensitive silver halide emulsion layer and the
upper layer consisting of a more sensitive silver halide emulsion, both partial layers
containing color-forming couplers in the same concentration. An element of this type
has, however, the disadvantage that the increase in sensitivity is accompanied by
an increase of granularity.
[0008] To overcome this disadvantage and lower the granularity of color images, GB 923,045
describes a method for increasing the sensitivity of a color photographic element
without coarsening the granularity of the dye image by providing an uppermost more
sensitive emulsion layer and a lowermost less sensitive emulsion layer, both layers
being sensitive to the same region of the visible spectrum and each containing non-diffusing
color couplers, with the maximum color density of the more sensitive emulsion layer
being adjusted to be lower than that of the less sensitive emulsion layer, in particular
being lower in an amount from 0.20 to 0.60.
[0009] US 3,516,831 describes a process for improving the sharpness of the color image,
according to which two layers which are sensitized to the same spectral region of
the spectrum contain different couplers, the more sensitive emulsion layer containing
4-equivalent couplers and the less sensitive emulsion layer 2-equivalent couplers.
[0010] Both processes described in GB 923,045 and US 3,516,831 have numerous disadvantages,
for example a worsening of granularity in high-sensitivity photographic elements.
A process for improving granularity is described in US 3,726,681 wherein granularity
of high-sensitivity photographic elements is improved by using a coupler having a
fast coupling reaction rate in a more sensitive silver halide emulsion layer and a
coupler having a slow coupling reaction rate in a less sensitive silver halide emulsion
layer. Since, however, sharpness is not sufficiently improved, EP 107,112 describes
a color photographic element in which at least one of the silver halide emulsion layers
is composed of two silver halide emulsion layers sensitive to the same color, the
more sensitive layer containing a high reaction rate coupler, and the less sensitive
silver halide emulsion layer containing a low reaction rate coupler in a range of
1/1.3 to 1/15 of that of the high reaction rate coupler and a diffusible DIR coupler.
The purpose of DIR couplers is to help in reducing graininess and improve sharpness
of the image due to intralayer or intraimage effects (that is in the same layers or
the same dye image) and improve color reproduction due to interlayer or interimage
effects (that is effect between different layers or different dye images).
[0011] Recently, the picture size of photographic films has been reduced to miniaturize
photo cameras, and silver halide grains have become coarser to increase sensitivity
of photographic elements. Therefore, the degrading tendency of the granularity has
been increased, even if the aforesaid double layer system is used.
[0012] US 3,843,369 describes a method for further increasing the sensitivity of a color
photographic element by providing three emulsion layers sensitive to the same spectral
region of visible light, the uppermost silver halide emulsion layer having the highest
light sensitivity and the lowermost silver halide emulsion layer having the lowest
light sensitivity, the uppermost and the intermediate layer each having a maximum
density of 0.6 or less.
[0013] US 4,582,780 describes a method for increasing sensitivity and improving adjacency
effects by providing three emulsion layers sensitive to the same spectral region of
visible light, the uppermost silver halide emulsion layer having the highest light
sensitivity and the lowermost silver halide emulsion layer having the lowest light
sensitivity, wherein the maximum color density of the uppermost silver halide emulsion
layer, after color development, is lower than 0.60 and the maximum color densities
of both the intermediate and the lowermost silver halide emulsion layers, after color
development, are each higher than 0.60.
[0014] EP 583,020 discloses a technique for improving granularity by providing a multilayer
color photographic elements comprising a plurality of blue, green and three red sensitive
silver halide emulsion layers, the layers being arranged on the support in the sequence:
a red least sensitive layer, a green least sensitive layer, a red mid-sensitive layer,
a red most sensitive layer, a green most sensitive layer, a blue most sensitive layer,
and a blue least sensitive layer.
[0015] EP 608,464 discloses a technique for enhancing the speed-granularity relationship
of dye images by providing multicolor photographic elements containing blue, green
and red sensitive layer units wherein at least one layer unit contains three superimposed
silver halide emulsion layers of different sensitivity comprising silver bromoiodide
tabular grains of different iodide content.
[0016] It is known that 2-equivalent 5-pyrazolone magenta couplers having an arylthio group
attached to the 4-position of the pyrazolone ring have a number of advantages compared
to 4-equivalent 5-pyrazolone magenta couplers in which the 4-position of the pyrazolone
ring is free (that is having only hydrogen atoms). For example, 2-equivalent 5-pyrazolone
couplers require only two equivalent of silver to produce each molecule of dye, are
less sensitive to certain chemical vapors, for example formaldehyde, and have high
dye light and dye dark stability. However, 2-equivalent 5-pyrazolone magenta couplers
have the disadvantage that they may cause worsening of granularity.
SUMMARY OF THE INVENTION
[0017] The present invention relates to a multilayer color photographic element comprising
a support having coated thereon red-, green- and blue-sensitive silver halide emulsion
layers comprising, respectively, cyan, magenta and yellow dye-forming couplers, wherein
the green-sensitive layer comprises three green-sensitive layers having different
sensitivity, an uppermost green-sensitive layer being more sensitive than an intermediate
green-sensitive layer which is more sensitive than a lowermost green-sensitive layer,
the layers arranged with the lowermost green-sensitive layer being closer to the support,
the intermediate green-sensitive layer being adjacent said lowermost green-sensitive
layer and the uppermost green-sensitive layer being above the intermediate green-sensitive
layer, characterized in that the uppermost green-sensitive emulsion layer comprises
4-equivalent 5-pyrazolone magenta dye-forming couplers, and the intermediate and the
lowermost green-sensitive emulsion layers comprise 2-equivalent 4-arylthio-5-pyrazolone
magenta dye-forming couplers.
[0018] The color photographic elements containing the aforesaid layer arrangement provide
good speed-granularity relationship.
DETAILED DESCRIPTION OF THE INVENTION
[0019] In particular, said 2-equivalent 4-arylthio-5-pyrazolone magenta coupler for use
in this invention may be represented by 1-phenyl-3-anilino-4-phenylthio-5-pyrazolone
magenta couplers of the following formula (I):
wherein
a represents an integer from 0 to 3,
b represents an integer from 0 to 2,
R1 and R2 are each individually hydrogen, alkyl, alkoxy, halogen, aryl, aryloxy, acylamino,
sulfonamido, sulfamoyl, carbamoyl, arylsulfonyl, aryloxycarbonyl, alkoxycarbonyl,
alkoxysulfonyl, aryloxysulfonyl, alkylureido, arylureido, nitro, cyano, hydroxyl or
carboxy group,
R3 is halogen atom, alkyl group or aryl group,
X is a direct link or a linking group,
Ball is a ballasting group of such size and configuration as to render a group to
which it is attached non-diffusible in photographic coatings, and
the sum of the sigma values of R1, R3 and X-Ball is less than 1.3.
[0020] In the above formula, examples of R
1 and R
2 include hydrogen; alkyl group, including straight or branched chain alkyl group,
such as alkyl group containing 1 to 8 carbon atoms, for example methyl, trifluoromethyl,
ethyl, butyl, and octyl; alkoxy group, such as an alkoxy group having 1 to 8 carbon
atoms, for example methoxy, ethoxy, propoxy, 2-methoxyethoxy, and 2-ethylhexyloxy;
halogen, such as chlorine, bromine, and fluorine; aryl group, such as phenyl, naphthyl,
and 4-tolyl; aryloxy group, such as phenoxy, p-methoxyphenoxy, p-methylphenoxy, naphthyloxy,
and tolyloxy; acylamino group, such as acetamido, benzamido, butyramido, and t-butylcarbonamido;
sulfonamido group, such as methylsulfonamido, benzenesulfonamido, and p-toluylsulfonamido;
sulfamoyl group, such as N-methylsulfamoyl, N,N-diethylsulfamoyl, and N,N-dimethylsulfamoyl;
carbamoyl group, such as N-methylcarbamoyl, and N,N-dimethylcarbamoyl; arylsulfonyl,
such as tolylsulfonyl; aryloxycarbonyl group, such as phenoxycarbonyl; alkoxycarbonyl
group, such as alkoxycarbonyl group containing 2 to 10 carbon atoms, for example methoxycarbonyl,
ethoxycarbonyl, and benzyloxycarbonyl; alkoxysulfonyl group, such as alkoxysulfonyl
group containing 2 to 10 carbon atoms, for example methoxysulfonyl, octyloxysulfonyl,
and 2-ethylhexylsulfonyl; aryloxysulfonyl group, such as phenoxysulfonyl; alkylureido
group, such as N-methylureido, N,N-dimethylureido, and N,N-dibutylureido; arylureido
group, such as phenylureido; nitro, cyano, hydroxyl and carboxy group.
[0021] Examples of R
3 include halogen, such as chlorine, bromine, and fluorine; alkyl group, including
straight or branched chain alkyl group, such as alkyl group containing 1 to 8 carbon
atoms, for example methyl, trifluoromethyl, ethyl, butyl, and octyl; aryl group, such
as phenyl, naphthyl, and 4-tolyl.
[0022] "Ball" is a ballasting group, i.e., an organic group of such size and configuration
as to render a group to which it is attached non-diffusible from the layer in which
is coated in a photographic element. Said ballasting group may include an organic
hydrophobic residue having 8 to 32 carbon atoms bonded to the coupler either directly
or through a divalent linking group X, such as an alkylene, imino, ether, thioether,
carbonamido, sulfonamido, ureido, ester, imido, carbamoyl, and sulfamoyl group. Specific
examples of suitable ballasting groups include alkyl groups (linear, branched, or
cyclic), alkenyl groups, alkoxy groups, alkylaryl groups, alkylaryloxy groups, acylamidoalkyl
groups, alkoxyalkyl groups, alkoxyaryl groups, alkyl groups substituted with an aryl
group ar a heterocyclic group, aryl groups substituted with an aryloxyalkoxycarbonyl
group, and residues containing both an alkenyl or alkenyl long-chain aliphatic group
and a carboxy or sulfo water-soluble group, as described, for example, in US 3,337,344,
3,418,129, 3,892,572, 4,138,258, and 4,451,559, and in GB 1,494,777.
[0023] When the term "group" or "residue" is used in this invention to describe a chemical
compound or substituent, the described chemical material includes the basic group
or residue and that group or residue with conventional substitution. Where the term
"moiety" is used to describe a chemical compound or substituent, only the unsubstituted
chemical material is intended to be included. For example, "alkyl group" includes
not only such alkyl moiety as methyl, ethyl, butyl, octyl, stearyl, etc., but also
moieties bearing substituent groups such as halogen, cyano, hydroxyl, nitro, amino,
carboxylate, etc. On the other hand, "alkyl moiety" includes only methyl, ethyl, stearyl,
cyclohexyl, etc.
[0024] In the present invention, the sum of sigma values of substituents on the 1-phenyl
and 3-anilino groups, such as R
1, R
3 and -X-Ball is less than 1.3. The values of sigma constants can be easily found in
the published literature (see, for example, "The Chemists' Companion", A.J. Gordon
and R.A. Ford, John Wiley & Sons, New York, 1972, "Progress in Physical Organic Chemistry",
V. 13, R.W. Taft, John Wiley & Sons, New York, "Substituents Constants for Correlation
Analysis in Chemistry and Biology", C. Hansch and A.J. Leo, John Wiley & Sons, New
York, 1979, and "Comprehensive Medicinal Chemistry", A.J. Leo, Pergamon Press, New
York, V. 4, 1990), or can be calculated using the Medchem program (see "Comprehensive
Medicinal Chemistry", A.J. Leo, Pergamon Press, New York, V. 4, 1990). Generally,
sigma values increase with increasing electron withdrawing power of the substituent,
with hydrogen = zero. For sigma values, only the atoms close to the phenyl ring have
an electron withdrawing effect and remote atoms have no effect. Examples of sigma
values for chemical groups or atoms are as follows: alkyl group = -017, chlorine atom
= 0.23, alkoxycarbonyl group = 0.45, acylamino group = 0.21, sulfamoyl group = 0.57,
alkylsulfonyl group = 0.78, and carbamoyl = 0.36.
[0025] Among the couplers described above, a preferred embodiment is represented by the
above formula wherein the groups R
1 are chlorine atoms, a is 3, and the chlorine atoms are attached to the carbon atoms
in position 2, 4 and 6 with respect to the carbon atom attached to the nitrogen atom.
[0026] A particularly preferred embodiment is represented by the above formula wherein the
group R
3 is a chlorine atom.
[0027] Specific examples of 2-equivalent 1-phenyl-3-anilino-4-phenylthio-5-pyrazolone magenta
couplers for use in the present invention are illustrated below, but the present invention
should not be construed as being limited thereto.
[0028] Other illustrative couplers include:
wherein Q represents a coupling-off group according to the invention.
[0029] Illustrative coupling-off groups Q are as follows:
[0030] In particular, the 4-equivalent 5-pyrazolone magenta coupler for use in this invention
may be represented by the following formula (II):
wherein R
1, R
3 and a have the same meaning as in formula (I), and n represents 0 or 1.
[0031] Among the 4-equivalent 5-pyrazolone magenta dye-forming couplers, a preferred embodiment
is represented by the above formula (II) wherein the groups R
1 are chlorine atoms, a is 3, and the chlorine atoms are attached to the carbon atoms
in position 2, 4 and 6 with respect to the carbon atom attached to the nitrogen atom.
[0033] In the present invention, the green-sensitive layer is composed of three silver halide
emulsion layers sensitized to the same spectral region of the visible spectrum, the
uppermost silver halide emulsion layer of which having the highest sensitivity and
the lowermost silver halide emulsion layer having the lowest sensitivity, as described
for example in US 3,843,369 and US 4,582,780. The three silver halide emulsions are
arranged so that light travels through the uppermost highest sensitivity green-sensitive
layer before striking the lowermost lowest sensitivity green-sensitive layer. The
difference in sensitivity between the highest and the lowest green-sensitive layers,
as referred to herein, is preferably such that extended latitude in the photographic
element is achieved without an appreciable distortion of the shape of the sensitometric
curve. Generally, this difference in sensitivity should be within the range of from
about 0.2 to about 1 logE (E being dosage of exposure), and preferably will be about
0.3 to 0.6 logE. The intermediate medium sensitivity emulsion layer, having an intermediate
sensitivity between the sensitivity of the uppermost highest sensitivity emulsion
layer and the lowermost lowest sensitivity emulsion layer, generally has a sensitivity
difference from the highest sensitivity emulsion layer of 0.1 to 0.55 logE and a sensitivity
difference with the lowest sensitivity emulsion layer of 0.1 to 0.55 logE. Also, the
uppermost highest sensitivity green-sensitive emulsion layer produces upon development
a colored image of lower color density than the intermediate and the lowermost green-sensitive
emulsion layers. Generally, the uppermost highest sensitivity green-sensitive emulsion
layer is relatively "starved" with respect to its color coupler content in order to
improve granularity of this layer (as disclosed by US 3,843,369 and US 4,582,780).
That is, relatively smaller amounts of coupler are used in the highest sensitivity
layer, such that, upon exposure and development, this layer produces a colored image
which is less dense than that produced in the lowest sensitivity layer.
[0034] In the present invention, the uppermost highest sensitivity green-sensitive silver
halide emulsion layer comprises the 4-equivalent 5-pyrazolone magenta coupler, while
the intermediate medium sensitivity and the lowermost lowest sensitivity green-sensitive
silver halide emulsion layers comprise the 2-equivalent 5-pyrazolone magenta coupler
as described above. In the uppermost layer, the 4-equivalent 5-pyrazolone magenta
dye-forming coupler is preferably used in an amount ranging from 0.01 to 0.5 mol per
mol of silver halide, more preferably 0.02 to 0.1 mol, in the intermediate layer the
2-equivalent 5-pyrazolone magenta dye-forming coupler is preferably used in an amount
ranging from 0.01 to 0.5 mol per mol of silver halide, more preferably 0.02 to 0.1
mol , and in the lowermost layer the 2-equivalent 5-pyrazolone magenta dye- forming
coupler is preferably used in an amount ranging from 0.02 to 1.0 mol per mol of silver
halide, more preferably 0.04 to 0.2 mol.
[0035] The color photographic elements of the present invention can be conventional photographic
elements containing a silver halide as a light-sensitive substance.
[0036] The silver halides used in the multilayer color photographic elements of this invention
may be a fine dispersion (emulsion) of silver chloride, silver bromide, silver chloro-bromide,
silver iodo-bromide and silver chloro-iodo-bromide grains in a hydrophilic binder.
Preferred silver halides are silver iodo-bromide or silver iodo-chloro-bromide containing
1 to 20% mole silver iodide. In silver iodo-bromide emulsions or silver iodo-chloro-bromide,
the iodide can be uniformly distributed among the emulsion grains, or iodide level
can varied among the grains. The silver halides can have a uniform grain size or a
broad grain size distribution. The silver halide grains may be regular grains having
a regular crystal structure such as cubic, octahedral, and tetradecahedral, or the
spherical or irregular crystal structure, or those having crystal defects such as
twin plane, or those having a tabular form, or the combination thereof.
[0037] The term "cubic grains" according to the present invention is intended to include
substantially cubic grains, that is grains which are regular cubic grains bounded
by crystallographic faces (100), or which may have rounded edges and/or vertices or
small faces (111), or may even be nearly spherical when prepared in the presence of
soluble iodides or strong ripening agents, such as ammonia. Particularly good results
are obtained with silver halide grains having average grain sizes in the range from
0.2 to 3 µm, more preferably from 0.4 to 1.5 µm. Preparation of silver halide emulsions
comprising cubic silver iodobromide grains is described, for example, in Research
Disclosure, Vol. 184, Item 18431, Vol. 176, Item 17644 and Vol. 308, Item 308119.
[0038] Other silver halide emulsions for use in this invention are those which employ one
or more light-sensitive tabular grain emulsions. The tabular silver halide grains
contained in the emulsion of this invention have an average diameter:thickness ratio
(often referred to in the art as aspect ratio) of at least 2:1, preferably 2:1 to
20:1, more preferably 3:1 to 14:1, and most preferably 3:1 to 8:1. Average diameters
of the tabular silver halide grains suitable for use in this invention range from
about 0.3 µm to about 5 µm, preferably 0.5 µm to 3 µm, more preferably 0.8 µm to 1.5
µm. The tabular silver halide grains suitable for use in this invention have a thickness
of less than 0.4 µm, preferably less than 0.3 µm and more preferably less than 0.2
µm.
[0039] The tabular grain characteristics described above can be readily ascertained by procedures
well known to those skilled in the art. The term "diameter" is defined as the diameter
of a circle having an area equal to the projected area of the grain. The term "thickness"
means the distance between two substantially parallel main planes constituting the
tabular silver halide grains. From the measure of diameter and thickness of each grain
the diameter:thickness ratio of each grain can be calculated, and the diameter:thickness
ratios of all tabular grains can be averaged to obtain their average diameter:thickness
ratio. By this definition, the average diameter:thickness ratio is the average of
individual tabular grain diameter:thickness ratios. In practice, it is simpler to
obtain an average diameter and an average thickness of the tabular grains and to calculate
the average diameter:thickness ratio as the ratio of these two averages. Whatever
the used method may be, the average diameter:thickness ratios obtained do not greatly
differ.
[0040] In the silver halide emulsion layer containing tabular silver halide grains, at least
15%, preferably at least 25%, and, more preferably, at least 50% of the silver halide
grains are tabular grains having an average diameter:thickness ratio of not less than
2:1. Each of the above proportions, "15%", "25%" and "50%" means the proportion of
the total projected area of the tabular grains having a diameter:thickness ratio of
at least 2:1 and a thickness lower than 0.4 µm, as compared to the projected area
of all of the silver halide grains in the layer.
[0041] It is known that photosensitive silver halide emulsions can be formed by precipitating
silver halide grains in an aqueous dispersing medium comprising a binder, gelatin
preferably being used as a binder.
[0042] The silver halide grains may be precipitated by a variety of conventional techniques.
The silver halide emulsion can be prepared using a single-jet method, a double-jet
method, or a combination of these methods or can be matured using, for instance, an
ammonia method, a neutralization method, an acid method, or can be performed an accelerated
or constant flow rate precipitation, interrupted precipitation, ultrafiltration during
precipitation, etc. References can be found in Trivelli and Smith, The Photographic
Journal, Vol. LXXIX, May 1939, pp. 330-338, T.H. James, The Theory of The Photographic
Process, 4th Edition, Chapter 3, US Patent Nos. 2,222,264, 3,650,757, 3,917,485, 3,790,387,
3,716,276, 3,979,213, Research Disclosure, Dec. 1989, Item 308119 "Photographic Silver
Halide Emulsions, Preparations, Addenda, Processing and Systems", and Research Disclosure,
Sept. 1976, Item 14987.
[0043] One common technique is a batch process commonly referred to as the double-jet precipitation
process by which a silver salt solution in water and a halide salt solution in water
are concurrently added into a reaction vessel containing the dispersing medium.
[0044] In the double jet method, in which alkaline halide solution and silver nitrate solution
are concurrently added in the gelatin solution, the shape and size of the formed silver
halide grains can be controlled by the kind and concentration of the solvent existing
in the gelatin solution and by the addition speed. Double-jet precipitation processes
are described, for example, in GB 1,027,146, GB 1,302,405, US 3,801,326, US 4,046,376,
US 3,790,386, US 3,897,935, US 4,147,551, and US 4,171,224.
[0045] The single jet method in which a silver nitrate solution is added in a halide and
gelatin solution has been long used for manufacturing photographic emulsion. In this
method, because the varying concentration of halides in the solution determines which
silver halide grains are formed, the formed silver halide grains are a mixture of
different kinds of shapes and sizes.
[0046] Precipitation of silver halide grains usually occurs in two distinct stages. In a
first stage, nucleation, formation of fine silver halide grain occurs. This is followed
by a second stage, the growth stage, in which additional silver halide formed as a
reaction product precipitates onto the initially formed silver halide grains, resulting
in a growth of these silver halide grains. Batch double-jet precipitation processes
are typically undertaken under conditions of rapid stirring of reactants in which
the volume within the reaction vessel continuously increases during silver halide
precipitation and soluble salts are formed in addition to the silver halide grains.
[0047] In order to avoid soluble salts in the emulsion layers of a photographic material
from crystallizing out after coating and other photographic or mechanical disadvantages
(stickiness, brittleness, etc.), the soluble salts formed during precipitation have
to be removed.
[0048] In preparing the silver halide emulsions for use in the present invention, a wide
variety of hydrophilic dispersing agents for the silver halides can be employed. As
hydrophilic dispersing agent, any hydrophilic polymer conventionally used in photography
can be advantageously employed including gelatin, a gelatin derivative such as acylated
gelatin, graft gelatin, etc., albumin, gum arabic, agar agar, a cellulose derivative,
such as hydroxyethylcellulose, carboxymethylcellulose, etc., a synthetic resin, such
as polyvinyl alcohol, polyvinylpyrrolidone, polyacrylamide, etc. Other hydrophilic
materials useful known in the art are described, for example, in Research Disclosure,
Vol. 308, Item 308119, Section IX.
[0049] The silver halide grain emulsion for use in the present invention can be chemically
sensitized using sensitizing agents known in the art. Sulfur containing compounds,
gold and noble metal compounds, and polyoxylakylene compounds are particularly suitable.
In particular, the silver halide emulsions may be chemically sensitized with a sulfur
sensitizer, such as sodium thiosulfate, allylthiocyanate, allylthiourea, thiosulfinic
acid and its sodium salt, sulfonic acid and its sodium salt, allylthiocarbamide, thiourea,
cystine, etc.; an active or inert selenium sensitizer; a reducing sensitizer such
as stannous salt, a polyamine, etc.; a noble metal sensitizer, such as gold sensitizer,
more specifically potassium aurithiocyanate, potassium chloroaurate, etc.; or a sensitizer
of a water soluble salt such as for instance of ruthenium, rhodium, iridium and the
like, more specifically, ammonium chloropalladate, potassium chloroplatinate and sodium
chloropalladite, etc.; each being employed either alone or in a suitable combination.
Other useful examples of chemical sensitizers are described, for example, in Research
Disclosure 17643, Section III, 1978 and in Research Disclosure 308119, Section III,
1989.
[0050] The silver halide emulsion for use in the present invention can be spectrally sensitized
with dyes from a variety of classes, including the polymethyne dye class, which includes
the cyanines, merocyanines, complex cyanines and merocyanines, oxonols, hemioxonols,
styryls, merostyryls, and streptocyanine.
[0051] The cyanine spectral sensitizing dyes include, joined by a methine linkage, two basic
heterocyclic nuclei, such as those derived from quinoline, pyrimidine, isoquinoline,
indole, benzindole, oxazole, thiazole, selenazole, imidazole, benzoxazole, benzothiazole,
benzoselenazole, benzoimidazole, naphthoxazole, naphthothiazole, naphthoselenazole,
tellurazole, oxatellurazole.
[0052] The merocyanine spectral sensitizing dyes include, joined by a methine linkage, a
basic heterocyclic nucleus of the cyanine-dye type and an acidic nucleus, which can
be derived from barbituric acid, 2-thiobarbituric acid, rhodanine, hydantoin, 2-thiohydantoin,
2-pyrazolin-5-one, 2-isoxazolin-5-one, indan-1,3-dione, cyclohexane-1,3-dione, 1,3-dioxane-4,6-dione,
pyrazolin-3,5-dione, pentane-2,4-dione, alkylsulfonylacetonitrile, malononitrile,
isoquinolin-4-one, chromane-2,4-dione, and the like.
[0053] One or more spectral sensitizing dyes may be used. Dyes with sensitizing maxima at
wavelengths throughout the visible and infrared spectrum and with a great variety
of spectral sensitivity curve shapes are known. The choice and relative proportion
of dyes depends on the region of the spectrum to which sensitivity is desired and
on the shape of the spectral sensitivity desired.
[0054] Examples of sensitizing dyes can be found in Venkataraman,
The chemistry of Synthetic Dyes, Academic Press, New York, 1971, Chapter V, James,
The Theory of the Photographic Process, 4th Ed., Macmillan, !977, Chapter 8, F.M.Hamer,
Cyanine Dyes and Related Compounds, John Wiley and Sons, 1964, and in Research Disclosure 308119, Section III, 1989.
[0055] The silver halide emulsions for use in this invention can contain optical brighteners,
antifogging agents and stabilizers, filtering and antihalo dyes, hardeners, coating
aids, plasticizers and lubricants and other auxiliary substances, as for instance
described in Research Disclosure 17643, Sections V, VI, VIII, X, XI and XII, 1978,
and in Research Disclosure 308119, Sections V, VI, VIII, X, XI, and XII, 1989.
[0056] The silver halide emulsion for use in the present invention can be used for the manufacture
of multilayer light-sensitive silver halide color photographic elements, such as color
negative photographic elements, color reversal photographic elements, color positive
photographic elements, false color address photographic elements (such as those disclosed
in US 4,619,892) and the like, the preferred ones being color negative photographic
elements.
[0057] Silver halide multilayer color photographic elements for use in the present invention
usually comprise, coated on a support, at least two red sensitized silver halide emulsion
layers associated with cyan dye-forming color couplers, three green sensitized silver
halide emulsion layers associated with magenta dye-forming color couplers and at least
two blue sensitized silver halide emulsion layers associated with yellow dye-forming
color couplers. These elements additionally comprise other non-light sensitive layers,
such as intermediate layers, filter layers, antihalation layers and protective layers,
thus forming a multilayer structure. These color photographic elements, after imagewise
exposure to actinic radiation, are processed in a chromogenic developer to yield a
visible color image. The layer units can be coated in any conventional order, but
in a preferred layer arrangement the red-sensitive layers are coated nearest the support
and are overcoated by the green-sensitive layers, a yellow filter layer and the blue-sensitive
layers.
[0058] Suitable color couplers are preferably selected from the couplers having diffusion
preventing groups, such as groups having a hydrophobic organic residue of about 8
to 32 carbon atoms, introduced into the coupler molecule in a non-splitting-off position.
Such a residue is called a "ballast group". The ballast group is bonded to the coupler
nucleus directly or through an imino, ether, carbon-amido, sulfonamido, ureido, ester,
imido, carbamoyl, sulfamoyl bond, etc. Examples of suitable ballasting groups are
described in US patent 3,892,572.
[0059] Said non-diffusible couplers are introduced into the light-sensitive silver halide
emulsion layers. On exposure and color development, said couplers give a color which
is complementary to the light color to which the silver halide emulsion layers are
sensitive. Consequently, at least one non-diffusible cyan image-forming color coupler,
generally a phenol or an α-naphthol compound, is associated with red-sensitive silver
halide emulsion layers, 4-equivalent and 2-equivalent 5-pyrazolone non-diffusible
magenta image-forming color couplers are associated with green-sensitive silver halide
emulsion layers, and at least one non-diffusible yellow image-forming color coupler,
generally an acylacetanilide compound, is associated with blue-sensitive silver halide
emulsion layers.
[0060] As known, color couplers may be 4-equivalent and/or 2-equivalent couplers, the latter
requiring a smaller amount of silver halide for color production. As it is well known,
2-equivalent couplers derive from 4-equivalent couplers since, in the coupling position,
they contain a substituent which is released during coupling reaction. 2-equivalent
couplers which may be used in silver halide color photographic elements include both
those substantially colorless and those which are colored ("masking couplers"). The
2-equivalent couplers also include white couplers which do not form any dye on reaction
with the color developer oxidation products. The 2-equivalent color couplers include
also DIR couplers which are capable of releasing a diffusing development inhibiting
compound on reaction with the color developer oxidation products.
[0061] The most useful cyan-forming couplers are conventional phenol compounds and α-naphthol
compounds. Examples of cyan couplers can be selected from those described in US patents
2,369,929; 2,474,293; 3,591,383; 2,895,826; 3,458,315; 3,311,476; 3,419,390; 3,476,563
and 3,253,924; in British patent 1,201,110, and in Research Disclosure 308119, Section
VII, 1989.
[0062] The most useful magenta-forming couplers, which can be used in combination with the
4-equivalent and 2-equivalent magenta image-forming couplers described hereinbefore,
are conventional pyrazolone type compounds, indazolone type compounds, cyanoacetyl
compounds, pyrazolotriazole type compounds, etc., and particularly preferred are pyrazolone
type compounds. Magenta-forming couplers are described for example in US patents 2,600,788,
2,983,608, 3,062,653, 3,127,269, 3,311,476, 3,419,391, 3,519,429, 3,558,319, 3,582,322,
3,615,506, 3,834,908 and 3,891,445,in DE patent 1,810,464, in DE patent applications
2,408,665, 2,417,945, 2,418,959 and 2,424,467; in JP patent applications 20,826/76,
58,922/77, 129,538/74, 74,027/74, 159,336/75, 42,121/77, 74,028/74, 60,233/75, 26,541/76
and 55,122/78, and in Research Disclosure 308119, Section VII, 1989.
[0063] The most useful yellow-forming couplers are conventional open-chain ketomethylene
type couplers. Particular examples of such couplers are benzoylacetanilide type and
pivaloyl acetanilide type compounds. Yellow-forming couplers that can be used are
specifically described in US patents 2,875,057, 3,235,924, 3,265,506, 3,278,658, 3,369,859,
3,408,194, 3,415,652 3,528,322, 3,551,151, 3,682,322, 3,725,072 and 3,891,445, in
DE patents 2,219,917, 2,261,361 and 2,414,006, in GB patent 1,425,020, in JP patent
10,783/76 and in JP patent applications 26,133/72, 73,147/73, 102,636/76, 6,341/75,
123,342/75, 130,442/75, 1,827/76, 87,650/75, 82,424/77 and 115,219/77, and in Research
Disclosure 308119, Section VII, 1989.
[0064] Colored couplers can be used which include those described for example in US patents
3,476,560, 2,521,908 and 3,034,892, in JP patent publications 2,016/69, 22,335/63,
11,304/67 and 32,461/69, in JP patent applications 26,034/76 and 42,121/77 and in
DE patent application 2,418,959. The light-sensitive silver halide color photographic
element may contain high molecular weight color couplers as described for example
in US Pat. No. 4,080,211, in EP Pat. Appl. No. 27,284 and in DE Pat. Appl. Nos. 1,297,417,
2,407,569, 3,148,125, 3,217,200, 3,320,079, 3,324,932, 3,331,743, and 3,340,376, and
in Research Disclosure 308119, Section VII, 1989.
[0065] Colored cyan couplers can be selected from those described in US patents 3,934,802;
3,386,301 and 2,434,272, colored magenta couplers can be selected from the colored
magenta couplers described in US patents 2,434,272; 3,476,564 and 3,476,560 and in
British patent 1,464,361. Colorless couplers can be selected from those described
in British patents 861,138; 914,145 and 1,109,963 and in US patent 3,580,722 and in
Research Disclosure 308119, Section VII, 1989.
[0066] Also, couplers providing diffusible colored dyes can be used together with the above
mentioned couplers for improving graininess and specific examples of these couplers
are magenta couplers described in US Pat. No. 4,366,237 and GB Pat. No. 2,125,570
and yellow, magenta and cyan couplers described in EP Pat. No. 96,873, in DE Pat.
Appl. No. 3,324,533 and in Research Disclosure 308119, Section VII, 1989.
[0067] Also, among the 2-equivalent couplers are those couplers which carry in the coupling
position a group which is released in the color development reaction to give a certain
photographic activity, e.g. as development inhibitor or accelerator or bleaching accelerator,
either directly or after removal of one or further groups from the group originally
released. Examples of such 2-equivalent couplers include the known DIR couplers as
well as DAR, FAR and BAR couplers. Typical examples of said couplers are described
in DE Pat. Appl. Nos. 2,703,145, 2,855,697, 3,105,026, 3,319,428, 1,800,420, 2,015,867,
2,414,006, 2,842,063, 3,427,235, 3,209,110, and 1,547,640, in GB Pat. Nos. 953,454
and 1,591,641, in EP Pat. Appl. Nos. 89,843, 117,511, 118,087, 193,389, and 301,477
and in Research Disclosure 308119, Section VII, 1989.
[0068] Examples of non-color forming DIR coupling compounds which can be used in silver
halide color elements include those described in US patents 3,938,996; 3,632,345;
3,639,417; 3,297,445 and 3,928,041; in German patent applications S.N. 2,405,442;
2,523,705; 2,460,202; 2,529,350 and 2,448,063; in Japanese patent applications S.N.
143,538/75 and 147,716/75, in British patents 1,423,588 and 1,542,705 and 301,477
and in Research Disclosure 308119, Section VII, 1989.
[0069] In order to introduce the couplers into the silver halide emulsion layer, some conventional
methods known to the skilled in the art can be employed. According to US patents 2,322,027,
2,801,170, 2,801,171 and 2,991,177, the couplers can be incorporated into the silver
halide emulsion layer by the dispersion technique, which consists of dissolving the
coupler in a water-immiscible high-boiling organic solvent and then dispersing such
a solution in a hydrophilic colloidal binder under the form of very small droplets.
The preferred colloidal binder is gelatin, even if some other kinds of binders can
be used.
[0070] Another type of introduction of the couplers into the silver halide emulsion layer
consists of the so-called "loaded-latex technique". A detailed description of such
technique can be found in BE patents 853,512 and 869,816, in US patents 4,214,047
and 4,199,363 and in EP patent 14,921. It consists of mixing a solution of the couplers
in a water-miscible organic solvent with a polymeric latex consisting of water as
a continuous phase and of polymeric particles having a mean diameter ranging from
0.02 to 0.2 micrometers as a dispersed phase.
[0071] Another useful method is further the Fischer process. According to such a process,
couplers having a water-soluble group, such as a carboxyl group, a hydroxy group,
a sulfonic group or a sulfonamido group, can be added to the photographic layer for
example by dissolving them in an alkaline water solution.
[0072] Useful methods of introduction of couplers into silver halide emulsions are described
in Research Disclosure 308119, Section VII, 1989.
[0073] The layers of the photographic elements can be coated on a variety of supports, such
as cellulose esters supports (e.g., cellulose triacetate supports), paper supports,
polyesters film supports (e.g., polyethylene terephthalate film supports or polyethylene
naphthalate film supports), and the like, as described in Research Disclosure 308119,
Section XVII, 1989.
[0074] The photographic elements according to this invention, may be processed after exposure
to form a visible image upon association of the silver halides with an alkaline aqueous
medium in the presence of a developing agent contained in the medium or in the material,
as known in the art. The aromatic primary amine color developing agent used in the
photographic color developing composition can be any of known compounds of the class
of p-phenylendiamine derivatives, widely employed in various color photographic process.
Particularly useful color developing agents are the p-phenylendiamine derivatives,
especially the N,N-dialkyl-p-phenylene diamine derivatives wherein the alkyl groups
or the aromatic nucleus can be substituted or not substituted.
[0075] Examples of p-phenylene diamine developers include the salts of: N,N-diethyl-p-phenylendiamine,
2-amino-5-diethylamino-toluene, 4-amino-N-ethyl-N-(α-methanesulphonamidoethyl)-m-toluidine,
4-amino-3-methyl-N-ethyl-N-(α-hydroxyethyl)-aniline, 4-amino-3-(α-methylsulfonamidoethyl)-N,N-diethylaniline,
4-amino-N,N-diethyl-3-(N'-methyl-α-methylsulfonamido)-aniline, N-ethyl-N-methoxy-ethyl-3-methyl-p-phenylenediamine
and the like, as described, for instance, in US patents No. 2,552,241; 2,556,271;
3,656,950 and 3,658,525.
[0076] Examples of commonly used developing agents of the p-phenylene diamine salt type
are: 2-amino-5-diethylaminotoluene hydrochloride (generally known as CD2 and used
in the developing solutions for color positive photographic material), 4-amino-N-ethyl-N-(α-methanesulfonamidoethyl)-m-toluidine
sesquisulfate monohydrate (generally known as CD3 and used in the developing solution
for photographic papers and color reversal materials) and 4-amino-3-methyl-N-ethyl-N-(β-hydroxy-ethyl)-aniline
sulfate (generally known as CD4 and used in the developing solutions for color negative
photographic materials).
[0077] Said color developing agents are generally used in a quantity from about 0.001 to
about 0.1 moles per liter, preferably from about 0.0045 to about 0.04 moles per liter
of photographic color developing compositions.
[0078] In the case of color photographic materials, the processing comprises at least a
color developing bath and, optionally, a prehardening bath, a neutralizing bath, a
first (black and white) developing bath, etc. These baths are well known in the art
and are described for instance in Research Disclosure 17643, 1978, and in Research
Disclosure 308119, Sections XIX and XX, 1989.
[0079] After color development, the image-wise developed metallic silver and the remaining
silver salts generally must be removed from the photographic element. This is performed
in separate bleaching and fixing baths or in a single bath, called blix, which bleaches
and fixes the image in a single step. The bleaching bath is a water solution having
a pH equal to 5.60 and containing an oxidizing agent, normally a complex salt of an
alkali metal or of ammonium and of trivalent iron with an organic acid, e.g., EDTA.Fe.NH
4, wherein EDTA is the ethylenediaminotetracetic acid, or PDTA.Fe.NH
4, wherein PDTA is the propylene-diaminotetraacetic acid. While processing, this bath
is continuously aired to oxidize the divalent iron which forms while bleaching the
silver image and regenerated, as known in the art, to maintain the bleach effectiveness.
The bad working of these operations may cause the drawback of the loss of cyan density
of the dyes.
[0080] In addition to the above mentioned oxidizing agents, the blix bath can contain known
fixing agents, such as for example ammonium or alkali metal thiosulfates. Both bleaching
and fixing baths can contain other additives, e.g., polyalkyleneoxide compounds, as
described for example in GB patent 933,008 in order to increase the effectiveness
of the bath, or thioether compounds known as bleach accelerators.
[0081] The present invention will be illustrated with reference to the following examples,
but it should be understood that these examples do not limit the present invention.
EXAMPLE 1
[0082] A multilayer silver halide color photographic film A1 was prepared by coating a cellulose
triacetate support base, subbed with gelatin, with the following layers in the following
order:
(1) a layer of black colloidal silver dispersed in gelatin having a silver coverage
of 0.26 g/m2 and a gelatin coverage of 1.33 g/m2;
(2) a layer of low sensitivity red-sensitive silver halide emulsion comprising a sulfur
and gold sensitized low-sensitivity silver iodobromide emulsion (having 2.5% silver
iodide moles and a mean grain size of 0.18 µm), optimally spectrally sensitized with
sensitizing dyes S-1, S-2 and S-3, at a total silver coverage of 0.70 g/m2 and a gelatin coverage of 1.3 g/m2, containing the cyan dye-forming coupler C-1 at a coverage of 0.34 g/m2, the cyan dye-forming DIR coupler C-2 at a coverage of 0.02 g/m2 and the magenta colored cyan-dye forming masking coupler C3 at a coverage of 0.022
g/m2, dispersed in a mixture of triphenylphosphate and butylacetanilide;
(3) a layer of medium-sensitivity red-sensitive silver halide emulsion comprising
a sulfur and gold sensitized silver iodochlorobromide emulsion (having 7% silver iodide
moles, 5% silver chloride moles and a mean grain size of 0.45 µm), optimally spectrally
sensitized with sensitizing dyes S-1, S-2 and S-3, at a silver coverage of 0.82 g/m2 and a gelatin coverage of 0.79 g/m2, containing the cyan dye-forming coupler C-1 at a coverage of 0.28 g/m2, the cyan dye-forming DIR coupler C-2 at a coverage of 0.019 g/m2, and the magenta colored cyan dye-forming masking coupler C-3 at a coverage of 0.049
g/m2, dispersed in a mixture of triphenylphosphate and butylacetanilide;
(4) a layer of high-sensitivity red-sensitive silver halide emulsion comprising a
sulfur and gold sensitized silver iodobromide emulsion (having 12% silver iodide moles
and a mean grain size of 1.1 µm), optimally spectrally sensitized with sensitizing
dyes S-1, S-2 and S-3, at a silver coverage of 1.55 g/m2, and a gelatin coverage of 1.08 g/m2, containing the cyan dye- forming coupler C-1 at a coverage of 0.134 g/m2, the cyan dye-forming DIR coupler C-2 at a coverage of 0.003 g/m2, the cyan dye-forming coupler C-4 at a coverage of 0.051 g/m2, and the magenta colored cyan dye-forming masking coupler C-3 at a coverage of 0.013
g/m2, dispersed in a mixture of tricresylphosphate and butylacetanilide;
(5) an intermediate layer containing 1.13 g/m2 of gelatin, 0.069 g/m2 of 2,5-di-t-octylhydroquinone and 0.071 g/m2 of the hardener H-1;
(6) a layer of low sensitivity green sensitive silver halide emulsion comprising a
sulfur and gold sensitized silver iodobromide emulsion (having 2.5% silver iodide
moles and a mean grain size of 0.18 µm), at a silver coverage of 0.64 g/m2, optimally spectrally sensitized with sensitizing dyes S-4 and S-5, at a gelatin
coverage of 1.2 g/m2, containing the magenta dye-forming coupler M-1 at a coverage of 0.29 g/m2, the magenta dye-forming DIR coupler M-2 at a coverage of 0.009 g/m2, and the yellow colored magenta dye-forming couplers M-3 and M-4 at a coverage of
0.102 g/m2, dispersed in tricresylphosphate;
(7) a layer of medium-sensitivity green sensitive silver halide emulsion comprising
a sulfur and gold sensitized silver iodochlorobromide emulsion (having 7% silver iodide
moles, 5% silver chloride moles and a mean grain size of 0.45 µm), optimally spectrally
sensitized with sensitizing dyes S-4 and S-5, at a silver coverage of 0.74 g/m2 and a gelatin coverage of 0.9 g/m2, containing the magenta dye-forming coupler M-1 at a coverage of 0.23 g/m2, the magenta dye-forming DIR coupler M-2 at a coverage of 0.024 g/m2, and the yellow colored magenta dye forming couplers M-3 and M-4 at a coverage of
0.102 g/m2, dispersed in tricresylphosphate;
(8) a layer of high-sensitivity red-sensitive silver halide emulsion comprising a
sulfur and gold sensitized silver iodobromide emulsion (having 12% silver iodide moles
and a mean grain size of 1.1 µm), optimally spectrally sensitized with sensitizing
dyes S-4 and S-5, at a silver coverage of 1.5 g/m2 and a gelatin coverage of 1.2 g/m2, containing the magenta dye-forming coupler M-1 at a coverage of 0.106 g/m2, and the yellow colored magenta dye forming couplers M-3 and M-4 at a coverage of
0.084 g/m2, dispersed in tricresylphosphate;
(9) an intermediate layer containing 1.06 g/m2 of gelatin;
(10) a yellow filter layer containing 1.14 g/m2 of gelatin, 0.045 g/m2 of silver, and 0.065 g/m2 of the hardener H-1;
(11) a layer of low-sensitivity blue-sensitive silver halide emulsion comprising a
blend of 63% by weight of the low-sensitivity emulsion of layer (2) and of 37% by
weight of the medium-sensitivity emulsion of layer (3) at a total silver coverage
of 0.57 g/m2, optimally spectrally sensitized with sensitizing dye S-6, at a gelatin coverage
of 1.26 g/m2, containing the yellow dye forming coupler Y-1 at a coverage of 1.0 g/m2 and the yellow dye forming DIR coupler Y-2 at a coverage of 0.033 g/m2, dispersed in a mixture of diethyllauramide and dibutylphthalate;
(12) a layer of high-sensitivity blue sensitive silver halide emulsion comprising
a sulfur and gold sensitized silver iodobromide emulsion (having 12% silver iodide
moles and a mean grain size of 1.1 µm), optimally spectrally sensitized with sensitizing
dye S-6, at a silver coverage of 0.84 g/m2 and a gelatin coverage of 1.15 g/m2, containing the yellow dye-forming coupler Y-1 at a coverage of 0.282 g/m2 and the yellow dye forming DIR coupler Y-2 at a coverage of 0.03 g/m2, dispersed in a mixture of diethyllauramide and dibutylphthalate;
(13) a protective layer of 1.19 g/m2 of gelatin, comprising the UV absorber UV-1 at a coverage of 0.131 g/m2, the UV absorber UV-2 at a coverage of 0.131 g/m2, a fine grain silver bromide emulsion at a silver coverage of 0.22 g/m2; and
(14) a top coat layer of 0.86 g/m2 of gelatin containing 0.190 g/m2 of polymethylmethacrylate matting agent MA-1 in form of beads having an average diameter
of 2.5 micrometers, and the hardener H-2 at a coverage of 0.408 g/m2.
[0083] Film A2 was prepared in a similar manner as film A1, but containing in the 8th uppermost
highest sensitivity green-sensitive layer 0.175 g/m
2 of the magenta dye-forming coupler M1 and 0.006 g/m
2 of the magenta dye-forming DIR coupler M2.
[0084] Film A3 was prepared in a similar manner as film A1, but replacing in the 8th uppermost
highest sensitivity green-sensitive layer the magenta dye-forming coupler M1 with
0.246 g/m
2 of the magenta dye-forming coupler M6.
[0085] Film A4 was prepared in a similar manner as film A1, but replacing in the 8th uppermost
highest sensitivity green-sensitive layer the magenta dye-forming coupler M1 with
0.266 g/m
2 of the magenta dye-forming coupler M5.
[0086] Samples of films A1 to A4 were exposed to a light source having a color temperature
of 5,500 K (white light exposure). The exposed samples were then color processed using
the KODAK FLEXICOLOR (C41) process as described in
British Journal of Photography Annual, 1988, pp. 196-198, in the following sequence:
1. Color development
2. Bleach
3. Wash
4. Fix
5. Wash
[0087] For each processed sample, the characteristic curve for the green light absorption
was obtained conventionally. The following Table 1 reports values of fog (Dmin), maximum
optical density (Dmax), sensitivity in Log E at density of 0.2 above Dmin (Speed1),
toe contrast (Gamma), values of interimage effects (IIE) and granularity (RMS) for
the green-sensitive layer. The interimage effects were calculated as follows. Samples
of each film were exposed to a light source having a color temperature of 5,500 K
through a Kodak Wratten™ W99 filter and an optical step wedge (selective exposure).
Other samples of each film were exposed as above but without any filter (white light
exposure). All the exposed samples were developed as described above. Contrasts of
the obtained sensitometric curves for selective exposures (gamma
s) and white light exposures (gamma
w) were measured in the low dye-density or toe region. Interimage effects (IIE) are
calculated as follows:
wherein the higher the numbers, the better the interimage effects. The measure of
RMS granularity was made at density 1.0 above Dmin, using the ISO Standard 10505 (IOW
161): the lower the number, the lower the granularity of the image.
Table 1
Film |
M Coupler |
Layer |
Dmin |
Dmax |
Speed1 |
Gamma |
IIE |
RMS |
A1 |
M1 |
8th |
0.70 |
2.73 |
2.29 |
0.61 |
8 |
10.5 |
A2 |
M1 |
8th |
0.68 |
2.82 |
2.29 |
0.68 |
17 |
9.0 |
A3 |
M6 |
8th |
0.63 |
2.63 |
2.27 |
0.59 |
21 |
8.0 |
A4 |
M5 |
8th |
0.71 |
2.71 |
2.28 |
0.57 |
30 |
10.1 |
[0088] The data show that the overall image properties (inter-image effects and speed-granularity
relationship) of Films A3 and A4, containing in the uppermost highest sensitivity
green-sensitive emulsion layer 4-equivalent 5-pyrazolone magenta couplers according
to this invention, are better than comparison films A1 and A2 containing in all green-sensitive
emulsion layers a 2-equivalent 5-pyrazolone magenta coupler.
EXAMPLE 2
[0090] A multilayer color photographic film B1 was prepared similar to film A1 of Example
1, but having the following composition for the 6th, 7th and 8th green-sensitive layers:
(6) a layer of low sensitivity green sensitive silver halide emulsion comprising a
sulfur and gold sensitized silver iodobromide emulsion (having 2.5% silver iodide
moles and a mean grain size of 0.18 µm), optimally spectrally sensitized with sensitizing
dyes S-4 and S-5, at a silver coverage of 0.55 g/m2 and a gelatin coverage of 1.37 g/m2, containing the magenta dye-forming coupler M-1 at a coverage of 0.283 g/m2, the magenta dye-forming DIR coupler M-2 at a coverage of 0.07 g/m2, and the yellow colored magenta dye-forming couplers M-3 and M-4 at a coverage of
0.1 g/m2, dispersed in tricresylphosphate;
(7) a layer of medium-sensitivity green sensitive silver halide emulsion comprising
a sulfur and gold sensitized silver iodochlorobromide emulsion (having 7% silver iodide
moles, 5% silver chloride moles and a mean grain size of 0.45 µm), optimally spectrally
sensitized with sensitizing dyes S-4 and S-5, at a silver coverage of 0.81 g/m2 and a gelatin coverage of 1.05 g/m2, containing the magenta dye-forming coupler M-1 at a coverage of 0.144 g/m2, the magenta dye-forming DIR coupler M-2 at a coverage of 0.016 g/m2, and the yellow colored magenta dye forming couplers M-3 and M-4 at a coverage of
0.113 g/m2, dispersed in tricresylphosphate;
(8) a layer of high-sensitivity red-sensitive silver halide emulsion comprising a
sulfur and gold sensitized silver iodobromide emulsion (having 12% silver iodide moles
and a mean grain size of 1.1 µm), optimally spectrally sensitized with sensitizing
dyes S-4 and S-5, at a silver coverage of 1.56 g/m2 and a gelatin coverage of 1.23 g/m2, containing the magenta dye-forming coupler M-1 at a coverage of 0.116 g/m2, and the yellow colored magenta dye forming couplers M-3 and M-4 at a coverage of
0.051 g/m2, dispersed in tricresylphosphate;
[0091] A multilayer color photographic element B2 was prepared similar to film B1, but containing
in the 7th green-sensitive layer 0.218 g/m
2 of the magenta dye-forming coupler M1 and 0.0213 g/m
2 of the magenta dye-forming DIR coupler M2, and in the 8th green-sensitive layer 0.273
g/m
2 of the magenta dye-forming coupler M6 instead of coupler M1.
[0092] A multilayer color photographic element B3 was prepared similar to film B1, but containing
in the 7th green-sensitive layer 0.303 g/m
2 of the magenta dye-forming coupler M6 instead of coupler M1 and magenta dye-forming
DIR coupler M2 was omitted, and in the 8th green-sensitive layer 0.116 g/m
2 of the magenta dye-forming coupler M1.
[0093] Samples of films B1, B2 and B3 were exposed and processed as described in Example
1. For each processed sample, the characteristic curve for the green light absorption
was obtained conventionally. The following Table 2 reports values of fog (Dmin), maximum
optical density (Dmax), sensitivity in Log E at density of 0.2 above Dmin (Speed1),
toe contrast (Gamma), and values of interimage effects (IIE) and granularity (RMS,
at density 1.3 above Dmin) for the green-sensitive layers.
Table 2
Film |
M Coupler |
Layer |
Dmin |
Dmax |
Speed1 |
Gamma |
IIE |
RMS |
B1 |
M1 |
8th |
0.72 |
2.77 |
2.31 |
0.59 |
13 |
7.3 |
B2 |
M6 |
8th |
0.67 |
2.68 |
2.29 |
0.60 |
22 |
6.4 |
B3 |
M1 |
8th |
0.72 |
2.81 |
2.33 |
0.60 |
19 |
7.3 |
[0094] The data show that film B2, having the 4-equivalent 5-pyrazolone magenta coupler
in the uppermost highest sensitivity green-sensitive emulsion layer, gives better
interimage effects and granularity.