[0001] This invention is directed to radiography. In particular, it is directed to a radiographic
silver halide film that provides improved medical diagnostic images of soft tissues
such as in mammography and exhibits improved processing characteristics.
[0002] In conventional medical diagnostic imaging the object is to obtain an image of a
patient's internal anatomy with as little X-radiation exposure as possible. The fastest
imaging speeds are realized by mounting a dual-coated radiographic element between
a pair of fluorescent intensifying screens for imagewise exposure. 5% or less of the
exposing X-radiation passing through the patient is adsorbed directly by the latent
image forming silver halide emulsion layers within the dual-coated radiographic element.
Most of the X-radiation that participates in image formation is absorbed by phosphor
particles within the fluorescent screens. This stimulates light emission that is more
readily absorbed by the silver halide emulsion layers of the radiographic element.
[0003] While the necessity of limiting patient exposure to high levels of X-radiation was
quickly appreciated, the question of patient exposure to even low levels of X-radiation
emerged gradually. The separate development of soft tissue radiography, which requires
much lower levels of X-radiation, can be illustrated by mammography. The first intensifying
screen-film combination (imaging assembly) for mammography was introduced to the public
in the early 1970's. Mammography film generally contains a single silver halide emulsion
layer and is exposed by a single intensifying screen, usually interposed between the
film and the source of X-radiation. Mammography utilizes low energy X-radiation, that
is radiation that is predominantly of an energy level less than 40 keV.
[0004] U.S. Patent 6,033,840 (Dickerson) and U.S. Patent 6,037,112 (Dickerson) describe
asymmetric imaging elements and processing methods for imaging soft tissue.
[0005] In mammography, as in many forms of soft tissue radiography, pathological features
sought to be identified are often quite small and not much different in density than
surrounding healthy tissue. Thus, mammography is a very difficult task in medical
radiography. In addition, microcalcifications must be seen when they are as small
as possible to improve detection and treatment of breast cancers. As a result, mammographic
films often include relatively high amounts of silver and gelatin to maximize image
sharpness when used with a single intensifying screen. The higher amounts of silver
and gel may mean that the films are more difficult to process or require longer processing
times.
[0006] This invention provides a solution to the noted problems with a radiographic silver
halide film comprising a support having first and second major surfaces and that is
capable of transmitting X-radiation,
the radiographic silver halide film having disposed on the first major support
surface, one or more hydrophilic colloid layers including at least one cubic silver
halide grain emulsion layer, and on the second major support surface, one or more
hydrophilic colloid layers including at least one silver halide emulsion layer,
the film characterized wherein the cubic silver halide grain emulsion layer comprises
cubic silver halide grains comprising from 1 to 20 mol % chloride and from 0.25 to
1.5 mol % iodide, both based on total silver in the emulsion layer, which cubic silver
halide grains have an average ECD of from 0.65 to 0.8 µm.
[0007] Further, this invention provides a method of providing a black-and-white image comprising
exposing a radiographic silver halide film of this invention and processing it, sequentially,
with a black-and-white developing composition and a fixing composition, the processing
being carried out within 90 seconds, dry-to-dry.
[0008] This invention also provides a radiographic imaging assembly comprising a radiographic
silver halide film of this invention that is arranged in association with a fluorescent
intensifying screen.
[0009] The present invention provides a means for providing radiographic images for mammography
with a radiographic film that is readily processed using the conventional processing
solutions known in the art. In addition, all other desirable sensitometric properties
are maintained or improved (such as photographic speed). If desired, the amount of
silver used in the films can be reduced without a significant loss in photographic
speed.
[0010] These advantages are achieved by including certain cubic silver halide grains that
are comprised of specific amounts of chloride, iodide, and bromide. The critical amount
of iodide provides desired photographic speed and the critical amount of chloride
provides desired image tone and rapid processability.
[0011] FIG. 1 is a schematic cross-sectional illustration of a radiographic silver halide
film of this invention.
[0012] FIG. 2 is a schematic cross-sectional illustration of a radiographic imaging assembly
of this invention comprising a radiographic silver halide film of this invention arranged
in association with a single fluorescent intensifying screen in a cassette holder.
[0013] The term "contrast" as herein employed indicates the average contrast derived from
a characteristic curve of a radiographic film using as a first reference point (1)
a density (D
1) of 0.25 above minimum density and as a second reference point (2) a density (D
2) of 2.0 above minimum density, where contrast is ΔD (i.e. 1.75) ÷ Δlog
10E (log
10E
2- log
10E
1), E
1 and E
2 being the exposure levels at the reference points (1) and (2).
[0014] The term "dual-coated" is used to define a radiographic film having silver halide
emulsion layers disposed on both the front- and backsides of the support. The radiographic
silver halide films of the present invention are "dual-coated."
[0015] The term "fluorescent intensifying screen" refers to a screen that absorbs X-radiation
and emits light. A "prompt" emitting fluorescent intensifying screen will emit light
immediately upon exposure to radiation while "storage" fluorescent screen can "store"
the exposing X-radiation for emission at a later time when the screen is irradiated
with other radiation (usually visible light).
[0016] The radiographic silver halide films of this invention include a flexible support
having disposed on both sides thereof, one or more photographic silver halide emulsion
layers and optionally one or more non-radiation sensitive hydrophilic layer(s). The
silver halide emulsions in the various layers can be the same or different and can
comprise mixtures of various silver halide emulsions within the requirements of this
invention.
[0017] In preferred embodiments, the photographic silver halide film has at least one different
silver halide emulsion on each side of the support. It is also preferred that the
film has a protective overcoat (described below) over the silver halide emulsions
on each side of the support.
[0018] The support is preferably a transparent film support. In its simplest possible form
the transparent film support consists of a transparent film chosen to allow direct
adhesion of the hydrophilic silver halide emulsion layers or other hydrophilic layers.
[0019] Polyethylene terephthalate and polyethylene naphthalate are the preferred transparent
film support materials.
[0020] Preferably, the "frontside" of the support comprises one or more silver halide emulsion
layers, one of which contains predominantly cubic grains (that is, more than 50 weight
% of all grains). These cubic silver halide grains particularly include predominantly
(at least 69 mol %) bromide, and preferably up to 89.75 mol % bromide, based on total
silver in the emulsion layer. In addition, these cubic grains must have from 1 to
20 mol % chloride (preferably from 10 to 20 mol % chloride) and from 0.25 to 1.5 mol
% iodide (preferably from 0.5 to 1 mol % iodide), based on total silver in the emulsion
layer. The cubic silver halide grains in each silver halide emulsion unit (or silver
halide emulsion layers) can be the same or different.
[0021] The amount of chloride in the cubic silver halide grains is critical to provide desired
processability and image tone while the amount of iodide is critical to provide desired
photographic speed. Too much chloride results in poor absorption of spectral sensitizing
dyes to the grains.
[0022] It may also be desirable to employ silver halide grains that exhibit a coefficient
of variation (COV) of grain ECD of less than 20% and, preferably, less than 10%. In
some embodiments, it may be desirable to employ a grain population that is as highly
monodisperse as can be conveniently realized.
[0023] The average silver halide grain size can vary within each emulsion layer within the
film. For example, the cubic grain ECD in the radiographic silver halide film is independently
and generally from 0.65 to 0.8 µm (preferably from 0.7 to 0.75 µm).
[0024] The backside ("second major support surface") of the support includes one or more
silver halide emulsions, preferably at least one of which comprises predominantly
tabular silver halide grains. Generally, at least 50% (and preferably at least 80%)
of the silver halide grain projected area in this silver halide emulsion layer is
provided by tabular grains having an average aspect ratio greater than 5, and more
preferably greater than 10. The remainder of the silver halide projected area is provided
by silver halide grains having one or more non-tabular morphologies. In addition,
the tabular grains are predominantly (at least 90 mol %) bromide based on the total
silver in the emulsion layer and includes up to 1 mol % iodide. Preferably, the tabular
grains are pure silver bromide.
[0025] The backside of the radiographic silver halide film also preferably includes an antihalation
layer disposed over the silver halide emulsion layer(s). This layer comprises one
or more antihalation dyes or pigments dispersed on a suitable hydrophilic binder (described
below). In general, such antihalation dyes or pigments are chosen to absorb whatever
radiation the film is likely to be exposed to from a fluorescent intensifying screen.
For example, pigments and dyes that can be used as antihalation pigments or dyes include
various watersoluble, liquid crystalline, or particulate magenta or yellow filter
dyes or pigments including those described for example in U.S. Patent 4,803,150 on
et al.), U.S. Patent 5,213,956 (Diehl et al.), U.S. Patent 5,399,690 (Diehl et al.),
U.S. Patent 5,922,523 (Helber et al.), U.S. Patent 6,214,499 (Helber et al.), and
Japanese Kokai 2-123349. One useful class of particulate antihalation dyes includes
nonionic polymethine dyes such as merocyanine, oxonol, hemioxonol, styryl, and arylidene
dyes as described in U.S. Patent 4,803,150 (noted above) that is incorporated herein
for the definitions of those dyes. The magenta merocyanine and oxonol dyes are preferred
and the oxonol dyes are most preferred.
[0026] The amounts of such dyes or pigments in the antihalation layer are generally from
1 to 3 mg/dm
2. A particularly useful antihalation dye is the magenta filter dye M-1 identified
as follows:

[0027] The silver halide emulsion layers and other hydrophilic layers on both sides of the
support of the radiographic films of this invention generally contain conventional
polymer vehicles (peptizers and binders) that include both synthetically prepared
and naturally occurring colloids or polymers. The most preferred polymer vehicles
include gelatin or gelatin derivatives alone or in combination with other vehicles.
[0028] The silver halide emulsion layers (and other hydrophilic layers) in the radiographic
films are generally hardened to various degrees using one or more conventional hardeners.
[0029] The levels of silver and polymer vehicle in the radiographic silver halide film of
the present invention are not critical. In general, the total amount of silver on
each side of the film is at least 10 and no more than 55 mg/dm
2 in one or more emulsion layers. In addition, the total coverage of polymer vehicle
on each side of the film is generally at least 35 and no more than 45 mg/dm
2 in all of the hydrophilic layers on that side. The amounts of silver and polymer
vehicle on the two sides of the support in the radiographic silver halide film can
be the same or different. These amounts refer to dry weights.
[0030] The radiographic silver halide films of this invention generally include a surface
protective overcoat disposed on each side of the support that typically provides physical
protection of the emulsion layers. Each protective overcoat can be sub-divided into
two or more individual layers.
[0031] The various coated layers of radiographic silver halide films of this invention can
also contain tinting dyes to modify the image tone to transmitted or reflected light.
These dyes are not decolorized during processing and may be homogeneously or heterogeneously
dispersed in the various layers. Preferably, such non-bleachable tinting dyes are
in a silver halide emulsion layer.
[0032] Preferred embodiments of this invention include radiographic silver halide films
comprising a support having first and second major surfaces and that is capable of
transmitting X-radiation, the radiographic silver halide films having disposed on
the first major support surface, one or more hydrophilic colloid layers including
at least one cubic silver halide grain emulsion layer, and on the second major support
surface, one or more hydrophilic colloid layers including at least one silver halide
emulsion layer comprising predominantly tabular silver halide grains, and an antihalation
layer,
wherein the silver halide cubic grain emulsion layer comprises predominantly cubic
silver halide grains comprising from 10 to 20 mol % chloride and from 0.5 to 1.5 mol
% iodide, both based on total silver in the emulsion layer, which cubic grains have
an average ECD of from 0.7 to 0.75 µm, and
a protective overcoat disposed over the silver halide emulsion layers on both sides
of the support.
[0033] The radiographic imaging assemblies of the present invention are composed of one
radiographic silver halide film of this invention and a fluorescent intensifying screen.
Usually, a single fluorescent intensifying screen is used on the "frontside" for mammography.
Fluorescent intensifying screens are typically designed to absorb X-rays and to emit
electromagnetic radiation having a wavelength greater than 300 nm. These screens can
take any convenient form providing they meet all of the usual requirements for use
in radiographic imaging.
[0034] An embodiment of the radiographic film of the present invention is illustrated in
FIG. 1. On the frontside of support
10 are disposed overcoat
20, and emulsion layer
30. On the backside of support
10 are disposed emulsion layer
50, antihalation layer
60, and overcoat
70.
[0035] FIG. 2 shows the radiographic film of FIG. 1 that is arranged in association with
fluorescent intensifying screen
80 on the frontside, and both in cassette holder
90.
[0036] Exposure and processing of the radiographic silver halide films of this invention
can be undertaken in any convenient conventional manner. The exposure and processing
techniques of U.S. Patent 5,021,327 and U.S. Patent 5,576,156 (both noted above) are
typical for processing radiographic films. Other processing compositions (both developing
and fixing compositions) are described in U.S. Patent 5,738,979 (Fitterman et al.),
U.S. Patent 5,866,309 (Fitterman et al.), U.S. Patent 5,871,890 (Fitterman et al.),
U.S. Patent 5,935,770 (Fitterman et al.), U.S. Patent 5,942,378 (Fitterman et al.).
The processing compositions can be supplied as single- or multi-part formulations,
and in concentrated form or as more diluted working strength solutions.
[0037] Exposing X-radiation is generally directed through a single fluorescent intensifying
screen before it passes through the radiographic silver halide film for imaging of
soft tissue such as breast tissue.
[0038] It is particularly desirable that the radiographic silver halide films of this invention
be processed within 90 seconds ("dry-to-dry") and preferably within 60 seconds and
at least 20 seconds, for the developing, fixing and any washing (or rinsing) steps.
Such processing can be carried out in any suitable processing equipment including
but not limited to, a Kodak X-OMAT™ RA 480 processor that can utilize Kodak Rapid
Access processing chemistry. Other "rapid access processors" are described for example
in U.S. Patent 3,545,971 (Barnes et al.) and EP 0 248,390A1 (Akio et al.). Preferably,
the black-and-white developing compositions used during processing are free of any
photographic film hardeners, such as glutaraldehyde.
[0039] Radiographic kits can include a radiographic silver halide film or imaging assembly
of this invention, one or more additional fluorescent intensifying screens and/or
metal screens, and/or one or more suitable processing compositions (for example black-and-white
developing and fixing compositions).
[0040] The following examples are presented for illustration and the invention is not to
be interpreted as limited thereby.
Example 1:
Radiographic Film A (Control):
[0041] Radiographic Film A was a dual-coated radiographic film with 2/3 of the silver and
gelatin coated on one side of the 170 µm blue-tinted poly(ethylene terephthalate)
support and the remainder coated on the opposite side of the support. The frontside
had a cubic grain emulsion chemically sensitized with sulfur and gold and spectrally
sensitized with Dye A-1 noted below. On the backside was an antihalation layer containing
solid particle dyes to provide improved sharpness over a green-sensitized high aspect
ratio tabular grain emulsion (Emulsion Layer 2). At least 50% of the total grain projected
area was accounted for by tabular grains having a thickness of less than 0.3 µm and
having an average aspect ratio greater than 8:1. The emulsion was monodisperse in
distribution and was spectrally sensitized with 400 mg/Ag mole of anhydro-5,5-dichloro-9-ethyl-3,3'-bis(3-sulfopropyl)oxacarbocyanine
hydroxide, followed by potassium iodide (300 mg/Ag mole).

[0042] Film A had the following layer arrangement and formulations on the film support:
Overcoat 1
Interlayer
Emulsion Layer 1
Support
Emulsion Layer 2
Halation Control Layer
Overcoat 2
| Overcoat 1 Formulation |
Coverage (mg/dm2) |
| Gelatin vehicle |
4.4 |
| Methyl methacrylate matte beads |
0.35 |
| Carboxymethyl casein |
0.73 |
| Colloidal silica (LUDOX AM) |
1.1 |
| Polyacrylamide |
0.85 |
| Chrome alum |
0.032 |
| Resorcinol |
0.73 |
| Dow Coming Silicone |
0.153 |
| TRITON X-200 surfactant (Union Carbide) |
0.26 |
| LODYNE S-100 surfactant (Ciba Specialty Chem.) |
0.0097 |
| Interlayer Formulation |
Coverage (mg/dm2) |
| Gelatin vehicle |
4.4 |
| Emulsion Layer 1 Formulation |
Coverage (mg/dm2) |
| Cubic grain emulsion [AgBr 0.85 µm average ECD] |
40.3 |
| Gelatin vehicle |
29.6 |
| 4-Hydroxy-6-methyl-1,3,3a,7-tetraazaindene |
1 g/Ag mole |
| 1-(3-Acetamidophenyl)-5-mercaptotetrazole |
0.026 |
| Maleic acid hydrazide |
0.0076 |
| Catechol disulfonate |
0.2 |
| Glycerin |
0.22 |
| Potassium bromide |
0.13 |
| Resorcinol |
2.12 |
| Bisvinylsulfonylmethane |
0.4 % based on total gelatin in all layers on that side |
| Emulsion Layer 2 Formulation |
Coverage (mg/dm2) |
| Tabular grain emulsion [AgBr 1.8 x 0.12 µm average size] |
10.9 |
| Gelatin vehicle |
16.4 |
| 4-Hydroxy-6-methyl-1,3,3a,7-tetraazaindene |
2.1 g/Ag mole |
| 1-(3-Acetamidophenyl)-5-mercaptotetrazole |
0.013 |
| Maleic acid hydrazide |
0.0032 |
| Catechol disulfonate |
0.2 |
| Glycerin |
0.11 |
| Potassium bromide |
0.06 |
| Resorcinol |
1.0 |
| Bisvinylsulfonylmethane |
2 % based on total gelatin in all layers on that side |
| Halation Control Layer |
Coverage (mg/dm2) |
| Magenta filter dye M-1 (noted above) |
2.2 |
| Gelatin |
10.8 |
| Overcoat 2 Formulation |
Coverage (mg/dm2) |
| Gelatin vehicle |
8.8 |
| Methyl methacrylate matte beads |
0.14 |
| Carboxymethyl casein |
1.25 |
| Colloidal silica (LUDOX AM) |
2.19 |
| Polyacrylamide |
1.71 |
| Chrome alum |
0.066 |
| Resorcinol |
0.15 |
| Dow Corning Silicone |
0.16 |
| TRITON X-200 surfactant |
0.26 |
| LODYNE S-100 surfactant |
0.01 |
Radiographic Film B (Invention)
[0043] Film B was like Film A except that Emulsion Layer 1 contained a AgICIBr (0.5:15:84.5
halide mole ratio) cubic grain emulsion (0.71 µm average ECD) that was chemically
sensitized with sulfur and gold and spectrally sensitized with a 340 mg/mole of Ag
of Dye A-1 noted above, and Emulsion Layer 2 had the following formulation:
| Emulsion Layer 2 Formulation |
Coverage (mg/dm2) |
| Tabular grain emulsion [AgBr 2.0 x 0.10 µm average size] |
16.1 |
| Gelatin vehicle |
10.8 |
| 4-Hydroxy-6-methyl-1,3,3a,7-tetraazaindene |
2.1 g/Ag mole |
| 1-(3-Acetamidophenyl)-5-mercaptotetrazole |
0.013 |
| Maleic acid hydrazide |
0.0032 |
| Catechol disulfonate |
0.2 |
| Glycerin |
0.11 |
| Potassium bromide |
0.06 |
| Resorcinol |
1.0 |
| Bisvinylsulfonylmethane |
2 % based on total gelatin in all layers on that side |
Radiographic Film C (Control):
[0044] Film C was like Film A except that Emulsion Layer 1 contained AgIClBr (0.5:25:74.5
halide mole ratio) cubic grain emulsion that was chemically sensitized with sulfur
and gold and spectrally sensitized with a 285 mg/mole of Ag of Dye A-1 noted above.
[0045] Samples of the films were exposed through a graduated density step tablet to a MacBeth
sensitometer for 0.5 second to a 500-watt General Electric DMX projector lamp that
was calibrated to 2650°K filtered with a Coming C4010 filter to simulate a green-emitting
X-ray screen exposure. The film samples were processed using a processor commercially
available under the trademark KODAK RP X-OMAT® film Processor M6A-N, M6B, or M35A.
Development was carried out using the following black-and-white developing composition:
| Hydroquinone |
30 g |
| Phenidone |
1.5 g |
| Potassium hydroxide |
21 g |
| NaHCO3 |
7.5 g |
| K2SO3 |
44.2 g |
| Na2S2O5 |
12.6 g |
| Sodium bromide |
35 g |
| 5-Methylbenzotriazole |
0.06 g |
| Glutaraldehyde |
4.9 g |
| Water to 1 liter, pH 10 |
|
[0046] The film samples were processed in each instance for less than 90 seconds. Fixing
was carried out using KODAK RP X-OMAT® LO Fixer and Replenisher fixing composition
(Eastman Kodak Company).
[0047] Optical densities are expressed below in terms of diffuse density as measured by
a conventional X-rite Model 310TM densitometer that was calibrated to ANSI standard
PH 2.19 and was traceable to a National Bureau of Standards calibration step tablet.
The characteristic D vs. Log E curve was plotted for each radiographic film that was
imaged and processed. Speed was measured at a density of 1.4 + D
min. Gamma (contrast) is the slope (derivative) of the noted D vs. Log E curves.
[0048] Residual dye stain ("Dye Stain") was measured using spectrophotometric methods and
calculated as the difference between density at 505 nm that corresponds to the dye
absorption peak, and the density at 700 nm. This measurement corrects for differences
in film fog. Measurements were done on film samples that have been processed without
exposure and are nominally clear of developed silver except for fog silver. Processing
was carried out in an RP X-OMAT Processor Model 480RA using KODAK RA30 Developer and
KODAK LO Fixer.
[0049] The following TABLE I shows the relative sensitometry of Films A-C. Control Film
A had the lowest photographic speed and contrast and the highest dye stain.
TABLE I
| Film |
Average Cubic Grain ECD (µm) |
Grain Halide(s) (mol %) |
Relative Speed |
Contrast |
Dye Stain |
| A (Control) |
0.73 |
Br (100) |
408 |
3.5 |
0.06 |
| B (Invention) |
0.73 |
IClBr (0.5:15:84.5) |
420 |
4.3 |
0.04 |
| C (Control) |
0.71 |
IClBr (0.5:25:74.5) |
416 |
4.0 |
0.03 |
Example 2:
[0050] Further radiographic films were prepared similar to Film B of Example 1 but with
various silver halide ratios and grain sizes in Emulsion Layer 1. TABLE II below provides
the data for these films and the sensitometric results.
TABLE II
| Film |
Average Cubic Grain ECD (µm) |
Halide Molar Ratio |
Speed |
Gamma at Density of 1.0 |
| D (Control) |
0.72 |
AgBr |
400 |
4 |
| E (Control) |
0.71 |
AgIBr (0.5:99.5) |
404 |
4.2 |
| F (Control) |
0.73 |
AgClBr (15:85) |
405 |
4.5 |
| G (Invention) |
0.71 |
AgIClBr (0.5:15:84.5) |
409 |
4.6 |
| H (Control) |
0.75 |
AgICIBr (0.5:30:69.5) |
402 |
1.9 |
[0051] The data in TABLE II show that both speed and contrast increase with increasing chloride
up to 30 mole % chloride. However, at that upper level, contrast and speed were severely
affected. The reason for this is that it is extremely difficult to maintain good cubicity
and grain monodispersity for these grain size emulsions with such high amounts of
chloride. Only Film G of the present invention provided maximum speed and contrast.
Example 3:
[0052] Several radiographic films were prepared similar to Film B of Example 1 using cubic
silver halide grains with various amounts of iodide content. The chloride content
for the cubic grains in each film was 13.2 mol %. The following TABLE III shows the
various grain content and sensitometric results.
TABLE III
| Film |
Iodide Content (mol %) |
Speed |
Contrast |
| I (Control) |
0 |
400 |
3.96 |
| J (Control) |
0.1 |
401 |
4.11 |
| K (Invention) |
0.3 |
402 |
4.13 |
| L (Invention) |
0.5 |
406 |
4.42 |
| M (Invention) |
1 |
405 |
4.38 |
| N (Invention) |
1.5 |
408 |
4.27 |
| O (Control) |
2 |
408 |
3.88 |
[0053] The data in TABLE III show the effect of iodide incorporation on speed and contrast.
Speed increased with increased iodide levels and contrast also increased until the
iodide levels reached 1.5 mol %. At higher iodide content, contrast began to drop.
Films L, M, and N provided desirable speed and contrast.
[0054] The invention has been described in detail with particular reference to preferred
embodiments thereof, but it will be understood that variations and modifications can
be effected within the spirit and scope of the invention.
1. A radiographic silver halide film comprising a support having first and second major
surfaces and that is capable of transmitting X-radiation,
said radiographic silver halide film having disposed on said first major support
surface, one or more hydrophilic colloid layers including at least one cubic silver
halide grain emulsion layer, and on said second major support surface, one or more
hydrophilic colloid layers including at least one silver halide emulsion layer,
the film characterized wherein said silver halide cubic grain emulsion layer comprises cubic silver halide
grains comprising from 1 to 20 mol % chloride and from 0.25 to 1.5 mol % iodide, both
based on total silver in the emulsion layer, which cubic grains have an average ECD
of from 0.65 to 0.8 µm.
2. The film of claim 1 wherein said cubic silver halide grains are composed of from 10
to 20 mol % chloride, based on total silver in the emulsion layer, and from 0.5 to
1.5 mol % iodide, based on total silver in the emulsion layer.
3. The film of claims 1 or 2 wherein said cubic grains have an ECD of from 0.7 to 0.75
µm.
4. The film of any of claims 1 to 3 wherein said silver halide emulsion layer on said
second major support surface comprises predominantly tabular silver halide grains.
5. The film of any of claims 1 to 4 further comprising an antihalation layer disposed
on said second major support surface.
6. The film of any of claims 1 to 5 wherein the amount polymer vehicle on each side of
its support in a total amount of from 35 to 45 mg/dm2 and a level of silver on each side of from 10 to 55 mg/dm2.
7. A radiographic imaging assembly comprising the radiographic silver halide film of
any of claims 1 to 6 that is arranged in association with a fluorescent intensifying
screen.
8. The radiographic imaging assembly of claim 7 comprising a single fluorescent intensifying
screen.
9. A method of providing a black-and-white image comprising exposing the radiographic
silver halide film of any of claims 1 to 6, and processing it, sequentially, with
a black-and-white developing composition and a fixing composition, the processing
being carried out within 90 seconds, dry-to-dry.
10. The method of claim 9 being carried out for 60 seconds or less.