Note: Descriptions are shown in the official language in which they were submitted.
1~L80C18
BACKGROUND OF THE INVENTION
Diffusion transfer photographic products and processes are known to the
art and details relating thereto can be found in United States Patents Nos.
2,983,606; 3,415,644; 3,415,645; 3,415;646; 3,473,925; 3,482,972; 3,551,406;
3,573,042; 3,573,043; 3,573,044, 3,576,625; 3,576,626; 3,578,540; 5,569,333;
3,579,333; 3,594,164; 3,594,165; 3,597,200; 3,647,437; 3,672,486; 3,672,890;
3,705,184; 3,752,836; 3,857,865. Essentially, diffusion transfer photographic
products and processes involve film units having a photosensitive system includ-
ing at least one silver halide layer, usually integrated with an image-providing
material. After photoexposure, the photosensitive system is developed to estab-
lish an imagewise distribution of a diffusible image-providing material, at
least a portion of which is transferred by diffusion to an image-receiving layer
capable of mordanting or otherwise fixing the transferred image-providing mate-
rial. In some diffusion transfer products the transfer image is viewed by re-
flection after separation of the image-receiving element from the photosensitive
system. In other products, however, such separation is not required and instead
the transfer image-receiving layer is viewed against a reflecting background
usually provided by a dispersion of a white reflecting pigment, such as, for ex-
ample, titanium dioxide. The latter type of film unit is generally referred to
in the art as integral negative-positive film units and are described, for ex-
ample, in the above-mentioned United States Patents Nos. 3,415,644 and 3,594,165.
It is known in the art to incorporate polymeric latices into gelatin
silver halide emulsion layers to increase the flexibility of the silver halide
layer, thus eliminating the occurrence of fog due to stresses set up in the film
unit containing the aforementioned silver halide layer.
United States Patent No. 2,772,166 discloses gelatin silver halide
emulsions which also contain a hydrosol resulting from the emulsion polymeriza-
tion of a mixture of
- 2 -
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8~8
-3-
styrene, acrylonitrile or a vinylidene chloride with an
alkyl acrylate or alkyl methacrylate and acrylic acid.
The described hydrosol is used in the range of 1 to 10%
of the gelatin.
U. S. Patent No. 2,835,582 is directed to mix-
tures of gelatin and polymeric hydrosols in silver halide
layers wherein the hydrosol is prepared by polymerizing
at least one monoethylenically unsaturated monomer in the
presence of an ampholytic surface active agent. Among the
suitable monomeric materials are mentioned methylmeth-
acrylate and styrene. It is a requirement that the poly-
meric materials be film formers and the essence of the
invention resides in the presence of the ampholytic sur-
face active material to provide its enhanced compatibility
with gelatin.
U. S. Patent No. 3,157,510 is directed to gelatin
silver halide emulsions which also include a dispersion of
minute particles of a water insoluble soft acrylate polymer
resin at a level of about 5 to 40% by weight of gelatin.
U. S. Patent No. 3,325,286 is directed to gelatin
silver halide emulsions which include an aqueous dispersion
of a polymeric vinyl compound and at least one anionic
dispersing agent specified in the patent. The emulsion
layer also requires a polyoxyethylene compound as defined
in the patent. One of the polymeric materials recited is
a homopolymer of an ~-hydrocarbon substituted acrylic acid
ester.
U. S. Patent No. 3,547,650 is directed to gelatin-
silver halide emulsions which include an aqueous dispersion
of a polymeric vinyl compound dispersed with a mixture of
specified organic phosphates. One of the polymerized vinyl
compounds recited comprises a homopolymer of an
~-hydrocarbon substituted acrylic acid ester.
U. S. Patent No. 3,772,032 is directed to a
gelatin silver halide emulsion which includes a polymeric
latex prepared by emulsion polymerization in the presence
of at least 5% by weight of an emulsifying agent to reduce
the stress sensitivity of the emulsion. This patent states
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1~L8{3 0~3
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that employing the specified emulsifying agent at a level
of at least 5% by weight, no fog is found in emulsions
employing large amounts of methylmethacrylate in the
latex whereas normally the presence of even 50% of
methylmethacrylate in the latex results in intolerable
increases in fog.
U. S. Patent No. 3,773,517 is directed to gelatin-
silver halide emulsion which include a polymer latex pre-
pared by copolymerization of a monomer yieldins a water
insoluble homopolymer and a monomer yielding a water
soluble polymer. The patent requires the polymerization
to occur in the presence of a specified alkylaryl polyether
phosphate surface active agent. One of the monomers which
would produce a water insoluble homopolymer is an
alkylmethacrylate.
U. S. Patent No. 3,418,132 is directed to a photo-
graphic film unit which, in one embodiment, is particularly
suited for rapid access processing by virtue of the
incorporation of inert particles into at least one layer
of the photographic element. The inert particles include
starch, barium sulfate, calcium carbonate, synthetic resins
etc. The inert particles are in the range of 7 to 15
microns.
Film units containing contiguous silver halide
emulsion layers sensitive to the same spectral region are
known to the art as shown by the following representative
patents.
U. S. Patent No. 3,505,068 is directed to a
photographic element which contains overlying silver
halide emulsions wherein the first emulsion is a regular
silver haloiodide emulsion and the second contains grains
which have an iodide-free shell and a silver iodide core.
U. S. Patent No. 3,663,228 is directed to a
photographic film unit having a plurality of silver halide
emulsion layers divided into sets with each set of a
different speed while the layers in each set have the same
speed but are responsive to different spectral regions.
Color filters are disposed between the layers.
~1~8~
--5--
U. S. Patent No. 3,695,882, is directed to a
photosensitive element comprising a support carrying two
emulsions, each containing a non-diffusing color coupler.
Each emulsion has a different speed and different silver
halide-coupler molar ratio.
U. S. Patent No. 3,846,135 is directed to a
synergistic increase in the sensitivity of two superposed
silver halide layers when the lower layer is less sensitive
than the upper layer and has a maximum density of at least
1.5 compared to a maximum density of at least 0.9 for the
upper layer. The lower layer is about 5 to 15~ thick.
U. S. Patents Nos. 3,960,558 and 4,003,744 dis-
close diffusion transfer film units which employ split
silver halide emulsions having dye image-forming material
associated therewith and which, in fact, contain dye
image-forming material in one of said contiguous layers.
U. S. Patent No. 3,632,342 is directed to a
photographic element comprising a support carrying at least
one layer containing a high contrast silver halide emulsion
layer containing an acrylic latex material and an additional
silver halide layer containing a hydrophilic colloid which
is free of latex micelles. It is stated that discrete
micelles are preferred but that coalescing may occur.
Copolymers of hydrophilic and hydrophobic monomers are
disclosed.
.
1~4800~
SUMMARY OP THE INVENTION
.
The photographic film unit of the present invention comprises at least
a first photosensitive silver halide emulsion layer having associated therewith
a dye image-forming material, preferably a dye developer which is soluble and
diffusible in alkali as a function of the exposure and development of the silver
halide emulsion layer, and a polymeric layer dyeable by said dye image-providing
material wherein said dyeable polymeric later is at least in superposed rela-
tionship with said photosensitive element after exposure of said element and dur-
ing processing of the exposed photosensitive silver halide emulsion, that is,
during contact of said emulsion with the aqueous alkaline processing composition;
and wherein said photosensitive silver halide emulsion layer comprises photosen-
sitive silver halide grains disposed in a mixture of gelatin and inert particles
which are substantially non-swelling in alkali, compatible with gelatin, and
substantially non-film forming or non-coalescing; which particles are equal to
or less than the silver halide grains in average diameter and wherein the silver
halide grains are 2.5 microns or less in diameter.
Preferably the film units of the present invention are integral nega-
tive-positive film units of the types described, for example, in United States
Patents Nos. 3,415,644 and 3,647,437. Preferred inert particles are derived
from polymeric latices which comprise homopolymers of methylmethacrylate or
styrene.
The term "photosensitive silver halide emulsion layer" as used herein,
is intended to include a first and second photosensitive silver halide layer
sensitive to the same portion of the spectrum and in contiguous relationship
i.e., so-called "split emulsions", which will be described below in greater
detail.
11480~)8
Thus in a first embodiment there is provided a photosensitive element
for use in a diffusion transfer film unit which comprises a support carrying at
least one photosensitive silver halide layer having a dye image-forming material
associated therewith, wherein said silver halide layer comprises silver halide
grains, gelatin and inert particles which are substantially non-swelling in
aqueous alkali, compatible with gelatin, possess an index of refraction
sufficiently close to gelatin to prevent undue light scattering and substantial-
ly non-film forming; said inert particles being less than or equal to the silver
halide grains in average diameter but not less than 0.075 microns in average
diameter; said silver halide grains being 2.5 microns or less in average
diameter, said inert particle to gelatin ratio (weight basis) ranging from
0.5 - 1 to 10 - 1.
In a second embodiment there is provided a diffusion transfer film
unit comprising a support carrying at least one silver halide emulsion layer
having a dye image-forming material associated therewith and a dyeable
receiving layer adapted to receive a dye image diffusing thereto after photo-
exposure and processing of said silver halide emulsion layer; wherein said
silver halide layer comprises silver halide grains, gelatin and inert particles
which are substantially non-swelling in aqueous alkali, compatible with gelatin,
possess an index of refraction sufficiently close to gelatin to prevent undue
light scattering and substantially non-film forming; said inert particles being
less than or equal to the silver halide grains in average diameter but not less
than 0.075 microns in average diameter; said silver halide grains being 2.5
microns or less in average diameter, said inert particle to gelatin ratio
(weight basis) ranging from about 0.5 - 1 to 10 - 1.
In a third embodiment there is provided a photographic film unit which
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1148~308
comprises, in combination a photosensitive element having a diffusion transfer
image receiving element affixed at least one edge thereof, said photosensitive
element comprising a support carrying:
a) a red-sensitive silver halide unit having associated therewith a
cyan dye developer;
b) a green-sensitive silver halide unit having associated therewith
a magenta dye developer;
c) a blue-sensitive silver halide unit having associated therewith
a yellow dye developer; wherein said photosensitive and said image receiving
elements are adapted to be superposed with the support layers outermost; and
wherein at least one of said silver halide units comprises silver
halide grains, gelatin, possess an index of refraction sufficiently close to
gelatin to prevent undue light scattering and substantially non-film forming;
said inert particles being less or equal to the silver halide grains in average
diameter but not less than 0.075 microns in average diameter; said silver
halide grains being 2.5 microns or less in average diameter, said inert
particle to gelatin ratio (weight basis) ranging from about 0.5 - 1 to 10 - 1.
In a fourth embodiment there is provided a photosensitive element for
use in a diffusion transfer film unit which comprises a support carrying:
a) a first photosensitive silver halide layer distal to the exposure
surface of said element and comprising silver halide grains possessing a first
mean particle size;
b~ a second photosensitive silver halide layer having a second mean
particle size; said second photosensitive layer comprising silver halide grains
possessing a higher intrinsic speed than said first photosensitive silver halidelayer; said first and second photosensitive silver halide layers being in con-
-6b-
.
:.:
1148~)8
tiguous relationship and having associated therewith a dye image forming
material which is diffusible during processing as a function of the point-to-
point degree of silver halide exposure to actinic radiation; said first and
second photosensitive silver halide layers comprising silver halide grains,
gelatin and inert particles which are substantially non-swelling in aqueous
alkali, compatible with gelatin, possess an index of refraction sufficiently
close to gelatin to prevent undue light scattering and substantially non-film
forming; said inert particles being less than or equal to the silver halide
grains in average diameter but not less than 0.075 microns in average diameter;
said silver halide grains being 2.5 microns or less in average diameter, said
inert particle to gelatin ratio (weight basis) ranging from about 0.5 - 1 to
10 - 1.
In a fifth embodiment there is provided a photographic diffusion
transfer film unit comprising a support carrying at least one photosensitive
element comprising a first and second photosensitive silver halide layer and a
dyeable receiving layer adapted to receive a dye image diffusing thereto
after photoexposure and processing of said photosensitive element, said first
photosensitive silver halide layer being distal to the exposure surface of said
element and comprising silver halide grains possessing a first mean particle
size; said second photosensitive silver halide layer comprising silver halide
grains possessing a second mean particle size; said second photosenæitive layer
having a higher intrinsic speed than said first photosensitive silver halide
layer; said first and second photosensitive silver halide layers being in
contiguous relationship and having associated therewith a dye image forming
material which is diffusible during processing as a function of the point-to-
point degree of silver halide exposure to actinic radiation; said first and
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.
~48~110~
second photosensitive silver halide layers comprising silver halide grains,
gelatin, and inert particles which are substantially non-swelling in aqueous
alkali, compatible with gelatin, possess an index of refraction sufficiently
close to gelatin to prevent undue light scattering and substantially non-film
forming; said inert particles being less than or equal to the silver halide
grains in average diameker but not less than 0.075 microns in average diameter;
said silver halide grains being 2.5 microns or less in average diameter, said
inert particle to gelatin ratio (weight basis) ranging from about 0.5 - 1 to
10 - 1.
In a sixth embodiment there is provided a photographic film unit which
comprises, in combination:
a photosensitive element having a diffusion transfer image-receiving
element affixed at least one edge thereof, said photosensitive element compris-
ing a support carrying:
a) a red-sensitive silver halide unit having associated therewith a
cyan dye developer;
b) a green-sensitive s_lver halide unit having associated therewith
a magenta dye developer;
c~ a blue-sensitive silver halide unit having associated therewith a
yellow dye developer; wherein at least one said silver halide unit comprises:
1~ a first photosensitive silver halide layer distal to the exposure
surface of said film unit and comprising silver halide grains possessing a first
mean particle size
2~ a second photosensitive silver halide layer comprising silver
halide grains possessing a second mean particle size; said second photosensitive
layer having a higher intrinsic speed than said first photosensitive silver
,
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` 1~48~)08
halide layer; said first and second photosensitive silver halide layers being
in contiguous relationship and having associated therewith a dye image forming
material which is diffusible during processing as a function of the point-to-
point degree of silver halide exposure to actinic radiation; said fi-;st and
second photosensitive silver hc~lide layers comprising silver halide grains
gelatin and inert particles which are substantially non-swelling in aqueous
alkali, compatible with gelatin, possess an index of refraction sufficiently
close to gelatin to prevent undue light scattering and substantially non-film
forming; said inert particles being less than or equal to the silver halide
grains in average diameter but not less than 0.075 microns in average diameter;
said silver halide grains being 2.5 microns or less in average diameter, said
inert particle to gelatin ratio (weight basis) ranging from about 0.5 - 1 to
10 - 1 and wherein said photosensitive and said image-receiving elements are
adapted to be superposed with the support layers outermost.
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DETAILED DESCRIPTION OF THE` INVENTION
The present invention will be described with
respect to dye developers as the dye image-forming
materials although it will be understood that other dye
image-forming materials may be employed in the present
invention.
Dye developers are well known in the art. A dye
developer is a compound which contains a silver halide
developing moiety and the chromophoric system of a dye.
In multicolor processes, a dye developer providing an
image dye of appropriate color is associated with each
silver halide emulsion layer; for example, a cyan dye
developer with a red sensitive silver halide layer; a
magenta dye developer with a green sensitive silver halide
emulsion layer; and a yellow dye developer with a blue
sensitive silver halide emulsion layer. Unoxidized dye
developer is insoluble in water but soluble and mobile
in aqueous alkali. Oxidation of the dye developer as a
result of development of exposed silver halide results in
its immobilization, while unoxidized dye developer can
diffuse to the dyeable image-receiving layer producing a
positive image therein.
To provide rapid transfer of the unoxidized dye
developer and to avoid any unwanted interactions in the
negative, it is preferred that the unoxidized dye developer
pass through the associated silver halide emulsion layer
as rapidly as possible consistent with development thereof.
Since gelatin swells to a considerable degree upon contact
with the photographic processing composition and thus
would be a factor in slowing dye developer transfer, it is
desixable to form the silver halide emulsion layer with a
minimum of gelatin. The minimum quantity of gelatin
employed, however, is controlled to a great degree by the
size of the silver halide grains. Thus, it is desirable
to employ sufficient gelatin to retain the silver halide
grains within the layer, that is, to prevent any projection
of the grains or portion of the grains through the gelatin
layer at the interface into contact with adjacent layers.
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Thus, it will be seen that larger size grains,
as commonly employed for high speed emulsions, would
require more gelatin than smaller grains at the same
unit weight coverage to form a continuous layer without
any projection of the grains into contact with adjacent
layers.
By means of the present invention it has now
been found that the transfer of image-forming materials
through gelatin-silver halide emulsion layers can be
accelerated, while at the same time completely retaining
the silver halide grains within the layer and without
adversely affecting the photographic properties of the
film unit. In fact, unexpected photographic advantages
are achieved as evidenced by H & D curves showing a
reduction in slope, increased toe extent and enhanced
dynamic range.
As stated above, these advantages are achieved
by disposing in the gelatin-silver halide layer inert
particles which are substantially non-swelling in aqueous
alkali; which are compatible with gelatin to avoid coagula-
tion within the layer; which possess a refractive index
sufficiently close to that of gelatin to avoid undue light
scattering; which are substantially non-film forming
(film forming would further inhibit dye transfer) and
which are suffi~iently hard to retain their physical
identity as individual particles in the presence of aqueous
alkali and thus provide a non-swelling, sizeable mass to
bulk the gelatin layer.
Inert particles suitable for use in the present
invention include starch, barium sulfate, calcium carbonate,
cellulose esters such as cellulose acetate propionate,
cellulose esters such as ethyl cellulose, gloss, synthetic
resins such as polyvinyl acetate, polycarbonates, homo and
copolymers of styrene, inorganic oxides such as zinc oxide,
silica, titanium dioxide, magnesium oxide and aluminum
oxide, as well as hardened geIatin grains, calcium sulfate,
barium carbonate and the like.
As stated above, the preferred inert particles
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1~L48~0~
g
for use in the present invention are polymethylmeth-
acrylate and polystyrene and are provided for the film
unit by disposing polymethylmethacrylate latex or
polystyrene latex in the emulsion.
The film forming and hardness characteristics
of polymers are properties associated with the glass tran-
sition temperature of the polymer. Thus, the Tg of the
polymer should be above the temperature at which the
polymer is dried. Preferably, the Tg is above 35C, more
preferably, above 60C. In a particularly preferred
embodiment, the Tg is above 100C.
It should be understood that the polymer latex
may be a homopolymer or a copolymer provided that the
comonomers do not modify the copolymer to the extent that
the required properties are not retained.
The inert particles should be no larger than the
silver halide grains with which they are associated. In
the present invention the maximum average diameter of the
silver halide grains is 2.5 microns or less and preferably
less than 2.0 microns. Thus, the maximum average diameter
of the inert particles is 2.5 microns. The lower limit of
the particles is determined by the fact that one should
avoid packing of the particles such as would impede dye
transfer. Preferably, inert particles not less than 0.075
microns in diameter would be employed.
In a particularly preferred embodiment the inert
particles leave an average diameter which is 10-15% of the
average diameter of the silver halide grains associated
therewith.
The quantity of polymer latex to be employed may
be readily determined for any given silver halide emulsion.
For a given silver halide grain size, as the quantity of
gelatin decreases, the polymer gelatin ratio goes up to
keep the layer dimensions the same. Sufficient gelatin
must be present to keep the layer intact and prevent dusting
of the polymer particles. Preferably, a ratio (weight
basis) of 0.5 to 1 to 10 to 1 polymer latex (solids) to
gelatin is employed. Particularly preferred is a 1 to 1
~1~L8~08
--10--
ratio for fine grains (less than about 1~4~ and 6 to 1 for
coarse grains (greater than about 1.3,~). Thus, in a
preerred embodiment, the average mean diameter of the
fine grains is less than about 1~ and the large grains,
greater than 1.3~.
As stated above, the novel photosensitive silver
halide layer of the present invention may comprise a first
and second photosensitive silver halide layer in contiguous
relationship and which are responsive to substantially the
same spectral range. Thus, in an alternative embodiment,
the dif'usion transfer photographic film unit of the present
invention comprises a plurality of layers which include a
first photosensitive silver halide emulsion layer comprising
silver halide grains of a first mean particle size and a
second photosensitive silver halide emulsion layer compris-
ing silver halide grains of a second mean particle size;said first and second silver halide emulsion layers being
in contiguous relationship with the first silver halide
layer being distal to the exposure surface of the film unit
with respect to the second silver halide layer; said first
and second silver halide layers being free of dye image-
forming material but having associated therewith a dye
image-forming material which is diffusible as function of
the point-to-point degree of silver halide exposure to
actinic radiation, and a layer adapted to receive image-
~5 forming material diffusing thereto and means for applyingan aqueous processing composition therebetween wherein at
least one of said silver halide layers comprise gelatin and
inert particles as defined above. If inert particles are
employed in only one layer it is in the layer containing
the larger silver halide grains. The intrinsic speed of
the second silver halide emulsion layer is greater than
that of the first silver halide emulsion layer.
~ owever, when the thickness of the gelatin
associated with the layers falls to about 50% or less of
the mean volume diameter of the grains, the coated layers
do not retain their integrity but rather combine, inter-
mixing the grain siæes, so that the resulting combined
.
1148~08
silver halide layer functions as if a single layer of blended grain sizes were
coated, thus losing all the benefits achieved in a layered structure and introd-
ucing the drawbacks of ~he single layered, low gelatin system.
It is believed that the adv ntages of this invention result, at least
in part, by maintaining better separation of the development process of the in-
dividual grains as well as separation of the by-products of development by vir-
tue of incorporating the above-described inert particles. By employing such in-
ert particles in the layers, the layers retain their integrity with the differ-
ently sized silver halide particles retained in their own separate and distinct
layer.
As stated above, the intrinsic speed of the second silver halide lay-
er, i.e., the layer closest to the exposure surface, possesses a higher intrin-
sic speed than the first silver halide layer. Preferably, the speed difference
is at least about 2 stops and may range up to about 8 stops. In a particularly
preferred embodiment, the difference is about 5 stops.
The polymeric latices preferred for employment in the present inven-
tion may be prepared by known techniques. The following non-limiting example
illustrates the preparation of a latex preferred for use in the present inven-
tion.
Example A
Water 118 1.
Methyl methacrylate 51 kg.
Potassium persulfate 0.15 kg.
Ascorbic acid 0.01 kg.
Dowfax* 2A1 20% solution 1.275 kg.
(dodecyldiphenyl oxide
disulfonate sodium salt,
sold by Dow Chemical Co.,
Midland, Michigan)
A reactor was charged with 102 1. of demineralized water and the Dowfax
2Al and heated under nitrogen to 83C whereupon 7.65 kg. of methyl methacrylate
was added
*Trademark - 11 -
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and mixed until the temperature returned to 83C. After
5 min. at 83C, 4.93 kg. of initiator solution (0.15 kg.
of potassium persulfate and 14.79 kg. water) was added.
After the exotherm, the temperature was reduced to 85 C
and the remaining methyl methacrylate was added at a rate
of about 361 g/min. and the remaining initiator solution
at a rate of about 111 g/min. At the end of the monomer
and initiator addition, the temperature was maintained at
85C for 10 min. and then the ascorbic acid was added.
The resulting latex had a 30% solids and the latex parti-
cles had an average diameter of about a 0.125,~.
The following non-limiting examples illustrate
the present invention:
EXAMPLE 1 (Control)
A photosensitive element was prepared by coating,
in succession, on a gelatin subbed, opaque polyethylene
terephthalate film base, the following layers.
1. a layer comprising the cyan dye developer
HC - NH - O2S ~
Cll ~ 1 3
HO~ ~=C~ ,~C ~ NH--C
Nll--O S N=~ _ N (~
HO~ OH 1
~0
dispersed in gelatin and coated at a coverage of about
747 mgs/m2 of dye, about 1554 mgs/m2 of gelatin, about
270 mgs/m2 of 4'-methylphenylhydroquinone, and about
-13-
270 mgs/m2 of 2-phenyl benzimidazole;
2. a red-sensitive gelatino silver iodobromide
emulsion layer comprising a 50/50 blend of 1.05~ and
1.5~grains coated at a coverage of about 1280 mgs/m2 of
silver and about 768 mgs/m2 of gelatin;
3. an interlayer coated at a coverage of about
2500 mgs/m of a 60-30-4-6 tetrapolymer of butylacrylate,
diacetone acrylamide, styrene and methacrylic acid, and
about 77 mgs/m2 of polyacrylamide;
4. a layer comprising the magenta dye developer
~0--CH2--CH2~
N- SO ~ N -N ~ CH
15 ~IO-CH2- CH2~ 2 ~ / ~N -
1l2o ~
O OH
~ C _CH2_CH
H
dispersed in qelatin and coated at a coverage of about
646 mgs/m2 of dye and about 426 mgs/m2 of gelatin and about
229 mgs/m of 2-phenylbenzimidazole;
5. a green-sensitive gelatino silver iodobromide
emulsion layer coated at a coverage of about 753 mgs/m2 of
silver and about 347 mgs/m of gelatin;
6. an interlayer containing the tetrapolymer
referred to above in layer 3 at a coverage of about 1369
mgs/m2, about 24 mgs/m2 of polyacrylamide, and about
75 mgs/m2 succindialdehyde;
7. a layer comprising the yellow dye
developer
~4B~0~3
-14-
C3~170 ~ 3li7 NO2
O O
\Cr-" H2o
o OH
~1 ~H~CH
~ H
dispersed in gelatin and coated at a coveraqe of a~out
968 mgs/m2 of dye and about 450 mgs/m of ~élatin and about
208 mgs/m of 2-phenyl benzimidazole;
8. a blue-sensitive gelatino silver iodobrornide
emulsion layer coated at a coverage of about 1280 mgs/m of
silver, about 743 mgs/m2 of gelatin, and about 204 mgs/m2
Of 4'-methylphenylhydroquinone;
9. an overcoat layer coated at a coverage of
about 484 mgs/m2 gelatin and 43 mgs/m2 of carbon black.
An image-receiving element was prepared by coat-
ing the following layers in succession on a 4 mil polyethy-
lene terephthalate film base, said layers respectivelycomprising:
1. as a polymeric acid layer, the partial butyl
ester of polyethylene/maleic anhydride copolymer at a
coverage of about 28,000 mgs/m ;
2. a timing layer containing about a 75:1 ratio
of a 60-30-4-6 copolymer of butylacrylate, diacetone
acrylamide, styrene and methacrylic acid and polyvinyl
alcohol at a coverage of about 5600 mgs/m2; and
3. A polymeric image-receiving layer containing
3~ a 2:1 mixture, by weight, of polyvinyl alcohol and poly-4-
vinylpyridine, at a coverage of about 3300 mgs/m .
An aqueous alkaline solution was prepared
comprising:
.~
~ 8~08
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Weiqht ~
Potassium hydroxide 5.25
N-phenethyl-a-picolinium 1.27
bromide (50% solution in water)
Sodium carboxymethyl hydroxethyl cellulose 2.0
(Hercules Type 420H)
Titanium dioxide 37.4
10 6-methyl uracil 0.7
bis-(~-aminoethyl)-sulfide 0.022
Benzotriazole 5.48
Colloidal silica aqueous 0.55
dispersion (30/O SiO2)
N-2-hydroxyethyl-N,N',N'-tris- 0.75
carboxymethyl-ethylene diamine
4-aminop~razolo (3, 4d) pyrimidine 0.25
6-benzylamino-purine 0.41
20 Polyethylene glycol 0.45
(molecular weight 4J000)
Water 44.26
` ~,
1~8~08
-16-
OH OH
5C18B37O ~ COOH HOOC
~b
HOOC
~ ~ 2 16 33-n
~ ~
EX~MPLE 2
A second film unit was prepared as described
above except that layer 2, the green~sensitive silver halide
emulsion layer additionally contained 120 mgs/ft2
(1292 mgs/m ) (solids) of a polymethylmethacrylate latex
having an average particle size of about 0.125 and layer 6
was reduced in coverage by 40~.
The film units were processed in the following
manner:
The film unit was exposed with white light to a
multicolor target and the processing composition was spread
between the two elements in a layer approximately 0.0028"
thick in the dark.
The following sensitometer data (green light
reflection data in neutral column) was obtained in the
resulting multicolor reflection prints:
~1~8~08
-17-
TABLE 1
Control ExamPle 2
Dmax lo90 1.88
Slope 1.61 1.31
Toe Extent 34 48
Dynamic Range 17 23
1O5 Speed 2.11 2.16
0O45 Speed 1.46 1.34
From the foregoing it can be seen that a 30 unit
reduction in slope is achieved; an increase in toe extent
of about 14 units as well as an increase in dynamic range
of more than 5 units. The loss indicated in the other
properties is not considered significant; i.e., the
advantages far outweigh the slight decrease recorded in
DmaX and speed which, in fact, may be within experimental
error. It should be understood that these enhanced photo-
graphic results are obtained at the same time the magenta
dye transfer is accelerated.
EXAMPLE 3
To illustrate the rapid dye transfer achieved by
the novel invention the following structures were prepared:
A. On a polyester base was coated 25 mgs/ft2
(269 mgs/m2) of the cyan dye of Example 1; 50 mgs/ft2
(538 mgs/m2) of gelatin and 2 mgs/ft (21.5 mgs/m2) of
succinaldehyde.
B. Structure A was overcoated with 180 mgs/ft
(1938 mgs/m ) of derivatized gelatin.
C. Structure A was overcoated with 180 mgs/ft2
(1938 mgs/m2) of inert gelatin.
D. Structure A was overcoated with a ~ixture o~
gelatin (40 mgs/ft2) (431 mgs/m2) and polymethylmethacrylate
latex (160 mgs/ft ) (1722mgs/m2) (0.125~average diameter).
The processing composition described above was spread
between the above structures and the superposed dye-
:
: : :
.
1148008
-18-
image-receiving sheet described in Example l in a thickness
of 28 mils. The density of dye deposited in the receiving
sheet was measured as a function of time. The resulting
data are set forth below:
s
1~480~)8
I~
. ~ ~ ~ U~
, ..
~ N
.~ ~ O ~ ~
~)
U~ ~ ~ O,
_1 _~ O ~
I~Y
1: ~ Il~ 1` 0
~ .
_~ _l O O
a~ a~ a~ 0 _1
0 aD ~ ~ aD
. ~ .
O O O O
~q '
m ~
~ .q
E~ ~ o o o oo
~ CD CD
s~
13a
,
~ ~ .. 3 ~
~ ~ t. ~
1~48~308
-20-
The above table illustrates the adverse effect
gelatin has on dye transfer. The table also shows that a
layer with a greater coverage than the gelatin layer but
composed of gelatin and latex particles provides transfer
rates approaching that obtained with no overcoat at all,
especially in the initial time period.
The following non-limiting example illustrates
a particularly preferred film unit of the present invention:
EXAMPLE 4 (Control)
A photosensitive element was prepared by coating,
in succession, on a gelatin subbed, opaque polyethylene
terephthalate film base, the following layers:
1. a layer comprising the cyan dye developer
CH3
HC NH 02S ~
N---C C CH3
~ 02-NH-CH
~ ~ ~ ~ CH
~ l 1 2
H3 ~ h ~ ~ ~ ~ ~ ¦rH
1 N~ 2 \ / CH
CH2 ~ 1 3
~ ~ 802-NH-CH
H ~ 1~2
dispersed in qelatin and coated at a coverage of about
747 mgs~m~ of dye, about 1554 mgs/m2 of qeIatin, about
270 mgs/m2 of 4'-methylphenylhydroquinone, and about
270 mgs/m of 2-phenyl benzimidazole;
2. a red-sensitive gelatino silver iodobromide
emulsion layer coated at a coverage of about 1280 mgs/m2
of silver and about 768 mgs/m2 of gelatin;
3. an interlayer coated at a coverage of about
2500 mqs/m2 of a 60-30-4-6 tetrapolymer of butylacrylate,
.
" 1~48~08
-21-
diacetone acrylamide, styrene and methacrylic acid, and
about 77 mgs/m of polyacrylamide;
4. a layer comprising the magenta dye developer
HO-CH2-CH2~ /~,
HO-CH -C~l / 2 ~ ~ ~ N
~ O ~3
~ CN2-C~2~
disPersed in gelatin and coated at a coverage of about
6~6 mgs/m2 of dye and about 426 mgS/m of
gelatin and about 229 mgs/m2 f 2-phenylbenzimidazole;
5. a green-sensitive silver halide emulsion
unit consisting of a first layer of 0.6~ average mean
diameter grains coated at a level of about 366 mgs/m2 of
silver and about 161 mgs/m2 of gelatin and a second layer
of 1.42~ average mean diameter grains coated at a level of
about 387 mgs/m2 silver and about 186 mgs/m2 of gelatin
with a speed difference between said first and second
layer of about 5 stops;
6. an interlayer layer containing the
tetrapolymer referred to above in layer 3 at a coverage
of about 1369 mgs/m2, about 24 mgs/m2 of polyacrylamide,
and about 75 mgs/m2 succindialdehyde;
7. a layer comprising the yellow dye developer
11~8008
--22--
~<~3~7 2
r ~t2O
¦¦ ~H
10 ~ ~C--CH2-CH2 ~
dispersed in gelatin and coated at a coverage of about
~G~ mgs/m2 of dye and about 450 mgs/m of gelatin and about
208 mgs/m2 of 2-phenyl benzimidazole;
8. a blue-sensitive gelatino silver iodobromide
emulsion layer coated at a coverage of about 1280 mgs/m2
of silver, about 743 mgs/m2 of gelatin, and about 204
mgs/m2 of 4'-methylphenylhydroquinone;
9. an overcoat layer coated at a coverage of
20 about 484 mgs/m2 of gelatin and 43 mgs/m2 of carbon black.
EXAMPLE 5
A second film unit was prepared as described
except that in layer 5 each green-sensitive silver halide
emulsion layer additionally contained 4 times the coverage
25 of gelatin of a polymethylmethacrylate latex having an
average particle size of about 0~125,~and layer 6 was
reduced in coverage by 40%.
The film units of Examples 4 and 5 were pro-
cessed in the following manner, using the image-receiving
30 element and processing composition described in Example l.
The film unit was exposed to white light and the
processing composition was spread between the two elements
in a layer approximately 0.0028" thick in the dark.
The following sensitometer data (green light
35 reflection data in neutral column) was obtained in the
resulting multicolor reflection prints:
o~
TABLE 1
Example 3 Example 4
Control
Dmax 1.83 1.90
Slope 1.71 1.20
Toe Extent 37 51
Dynamic Range 17.150 28.990
1.5 Speed 2.21 2.14
0.45 Speed 1.55 1.24
From the foregoing it can be seen that a slight increase in D , a 51
unit reduction in slope, an increase in toe extent of about 14 units as well as
an increase in dynamic range of almost 12 units are achieved. The loss indicat-
ed in the other properties is not considered significant; i.e., the advantages
far outweigh the slight decreases recorded in speed. It should be understood
that these enhanced photographic results are obtained at the same time the dye
transfer is accelerated and silver halide layer integrity maintained.
It should be noted that the interlayer ~layer 6) adjacent the silver
halide emulsion layer containing the inert particles was reduced in coverage by
40%. This is an additional and unexpected advantage of the present invention
which further enhances dye transfer.
A film unit similar to Example 5 was prepared except that the polymer
latex employed was a 90/10 methylmethacrylate/hydroxypropyl acrylate copolymer.
Upon exposure and processing similar advantageous results were obtained.
- 23 -
. .
.
; ., :
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