US2309492A - Process for avoiding color fog on photographic color material - Google Patents

Process for avoiding color fog on photographic color material Download PDF

Info

Publication number
US2309492A
US2309492A US352402A US35240240A US2309492A US 2309492 A US2309492 A US 2309492A US 352402 A US352402 A US 352402A US 35240240 A US35240240 A US 35240240A US 2309492 A US2309492 A US 2309492A
Authority
US
United States
Prior art keywords
color
photographic
fog
hardening agent
reactive
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US352402A
Inventor
Albers Fritz
Frohlich Alfred
Schneider Wilhelm
Trabert Erwin
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
GAF Chemicals Corp
Original Assignee
General Aniline and Film Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by General Aniline and Film Corp filed Critical General Aniline and Film Corp
Application granted granted Critical
Publication of US2309492A publication Critical patent/US2309492A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • GPHYSICS
    • G03PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03CPHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
    • G03C7/00Multicolour photographic processes or agents therefor; Regeneration of such processing agents; Photosensitive materials for multicolour processes
    • G03C7/30Colour processes using colour-coupling substances; Materials therefor; Preparing or processing such materials
    • G03C7/407Development processes or agents therefor
    • G03C7/413Developers

Definitions

  • This invention relates to a processfor avoiding color-fog on photographic color material.
  • Pyrazolones for instance react with formaldehyde and oxidizing substances with the formation of tensely yellow-colored compounds. Since slight traces of formaldehyde are suificient to produce the undesired color-fog, it is extremely difficult to eliminate the formaldehyde in the manufacturing process to such an extent, that no detrimental consequences appear.
  • Another object is the manufacture of photographic color paper which is free from colorfog.
  • Suit-' able substances are for instance hydroxyl amines, hydrazine derivatives, for instance hydrazinesulfo acid, hydrazine dicarboxylic acid ethyl ester, i'n-methylhydrazine, a-quinolylhydrazine,
  • cyanacetylhydrazine hydrazo derivatives, for instance hydrazoisobutyro nitrile, semicarb aai des, forinstance semi-carbazide hydrochloride, 1,4- phenylsemicarbazide, dimethylhydroresorcin and naphthylene diamines, for instance 1,8-naphthylene diaminel-sulfo acid.
  • hydrazo derivatives for instance hydrazoisobutyro nitrile
  • semicarb aai des forinstance semi-carbazide hydrochloride
  • 1,4- phenylsemicarbazide dimethylhydroresorcin
  • naphthylene diamines for instance 1,8-naphthylene diaminel-sulfo acid.
  • the photographic emulsion layers contain color formers reactive with the oxidation products of an aromatic amino developer to form a dye in situ with the silver image, preferably those fast to diffusion according to the following U. S. patents: 2,178,612, 2,179,238, 2,179,244, 2,186,732, 2,186,8'z9, 2,186,850 and 2,280,772; and U. S. application Ser. No. 327,628, filed April 3, 1940, applied for on behalf of Frtilich et al.
  • improvement which comprises inhibiting the formation of said color fog by contacting said color material with an organic substance reactive with the aldehyde hardening agent and selected from the" class consisting of hydroxyl amines, hydrazines, hydrazo compounds, semicarbazides, naphthalene diamines, and dimethylhydroresorcines.
  • Photographic color material comprising a support carrying a silver halide emulsion'layer containing a color former reactive with the oxi dation products of an aromatic amino developer to form a dye in situ with the silver image, and an aldehyde hardening agent tending to react with said color former to produce color fog, said material also containing an organic substance reactive with the aldehyde hardening agent and selected from the class consisting of hydroxyl amines, hydrazines, hydrazo compounds, semicarbazides, naphthalene diamines, and dimethylhydroresorcines.
  • a photographic material for color forming development comprising a support layer, at least one silver halide emulsion layer containing a color former reactive with the oxidation products of an aromatic amino developer to form a dye in situ with the silver image, at least one intermediate layer, and a backing layer, at least one of said layers containing traces of an aidehyde hardening agent having the tendency to produce color fog with said color former, at least one of said layers containing a compound reactive with the aldehyde hardening agent and selected from the class consisting of hydroxyl amines, hydrazines, hydrazo compounds, semicarbazides, naphthalene diamines, and dimethylhydroresorcines.
  • a photographic material for color forming development comprising a support layer substantially consisting of a paper support and a barium sulfate layer, at least one silver halide gelatin emulsion layer containing a color former reactive with the oxidation products of an aromatic amino developer to form a dye in situ with the silver image, at least one intermediate layer, and a backing layer, said paper support and said emulsion layer containing traces of an aldehyde hardening agent having the tendency to produce color fog with said color former said paper least one of said layers an aldehyde hardening agent tending to react with the color former to produce color fog, and said gelatino silver halide emulsion also containing an organic substance reactive with the aldehyde hardening agent and selected from the class consisting of hydroxyl amines, hydrazines, hydrazo compounds, semi-.- carbazides, naphthalene diamlnes and dimethylhydroresorcines.
  • Multi-color photographic paper comprising a gelatino silver halide emulsion layer containing a color former reactive with the oxidation products of an aromatic developer to form a dye in situ with the silver image, a barium sulfate layer, and-a paper support for the photographic emulsion and the barium sulfate layer, said photographic material containing in at least one of said layers an aldehyde-hardening agent tending to react with the color former to produce color fog, said barium sulfate layer containing an organic substance reactive with the aldehyde hardening agent and selected from the class consisting of hydroxyl amines, hydrazines, hydrazo support additionally containing a compound reactive with the aldehyde hardening agent and selected from the class consisting of'hydroxyl amines, hydrazines, hydrazo compounds, semicarbazides, naphthalene diamines, and dimethylhydroresorcines.
  • a photographic material for color forming development comprising a support layer substantially consisting of a paper support and a barium sulfate layer, at least one silver halide gelatin emulsion layer containing a color former reactive with the oxidation products of an aromatic amino developer to form a dye in situ with the silver image, at least one intermediate layer and a backing layer, said barium sulfate layer and said emulsion layer containing traces of an aldehyde hardening.
  • barium sulfate layer additionally containing a compound reactive with the aldehyde hardening agent and selected from the class consisting of hydroxyl amines, hydrazines, hydrazo compounds, semi-carbazides, naphthalene diamines, and dimethylhydroresorc'ines.
  • photographic emulsion and said barium sulfate layer said photographic paper containing in at compounds, semi-carbazides, naphthalene diamines, and dimethylhydroresorcines.
  • a multi-color photographic paper comprising-- sulfate layer, at least one of said layers 'containing an aldehyde hardening agent, tending to react with the color former to produce color fog, said paper support containing an organic substance reactive with the aldehyde hardening agent and selected from the class consisting of hydroxyl amines, hydrazines, hydrazo compounds, semi-carbazides, naphthalene diamines, and dimethyldroresorcines.

Description

Jan. 26, 1943. F. ALBERS EI'AL 2,309,492
PROCESS FOR AVOIDING COLOR FOG ON PHOTOGRAPHIC COLOR MATERIAL Filed Aug. 13, 1940 AG-HAL/DE EMULSION LAYER CONTAIN/N6 COLOR F RMING DEVELOPMENT COMPONENT AND AN ALDEHYDE REACTIVE COMPOUND 0F THE GROUP CONS/STING 0F HYDROXYL AMINES, HYDRAZO co/wpo unmsw yo fiAZ/N Es, SEMICARBAZ 05s, NAPHTHALENE D/A M IN 55 BAR/UM SULFATE LAYER BASE CONTAINING ALDEHYDE HARDENINGAG'ENT FRITZ ALsERs A/vu AF/VED FHDHLIGH l/V/LHELM SCHNEIDER A/vfl fRw/N TRA BER T Patented Jan. 26 1943 PROCESS FOR AVOIDING COLOR FOG ON PHOTOGRAPHIC COLOR MATERIAL Fritz Albers, Leverkusen-Wiesdorf, Alfred Friihlich and Wilhelm Schneider, Dessau, and Erwin Trabert, Leverkusen-Wiesdorf, Germany, assignors to General Aniline & Film Corporation, New York, N. Y., a corporation of Delaware Application August'13, 1940, Se'rialNo. 352,402 In Germany July 14, 1939 12 Claims.
This invention relates to a processfor avoiding color-fog on photographic color material.
It is customary to use formaldehyde almost exclusively for the hardening of photographic emulsion layers, especially also of photographic papers. Also when manufacturing raw-paper and casting the bariumsulfate layer for photographic paper, formaldehyde is employed. If blackand-white-images are produced in such layers, the traces of formaldehyde remaining in the photographic material are not disturbing. It was found, however, that traces of formaldehyde influence considerably the whites of photographic emulsion layers containing color formers. The cause for it lies in the reactivity of the formaldehyde and other aldehydes with the color formers serving for the production of the color image. Pyrazolones for instance react with formaldehyde and oxidizing substances with the formation of tensely yellow-colored compounds. Since slight traces of formaldehyde are suificient to produce the undesired color-fog, it is extremely difficult to eliminate the formaldehyde in the manufacturing process to such an extent, that no detrimental consequences appear.
It is an object of this invention to produce photographic color materials being free from color-fog.
Another object is the manufacture of photographic color paper which is free from colorfog.
These and other objects will become apparent from the following specification. I
It has been found that it is possible to avoid the undesired color-fog in color photographic fog in the emulsion nor decrease its sensitivity nor precipitate or deluster the emulsion. Suit-' able substances are for instance hydroxyl amines, hydrazine derivatives, for instance hydrazinesulfo acid, hydrazine dicarboxylic acid ethyl ester, i'n-methylhydrazine, a-quinolylhydrazine,
cyanacetylhydrazine, hydrazo derivatives, for instance hydrazoisobutyro nitrile, semicarb aai des, forinstance semi-carbazide hydrochloride, 1,4- phenylsemicarbazide, dimethylhydroresorcin and naphthylene diamines, for instance 1,8-naphthylene diaminel-sulfo acid.
The photographic emulsion layers contain color formers reactive with the oxidation products of an aromatic amino developer to form a dye in situ with the silver image, preferably those fast to diffusion according to the following U. S. patents: 2,178,612, 2,179,238, 2,179,244, 2,186,732, 2,186,8'z9, 2,186,850 and 2,280,772; and U. S. application Ser. No. 327,628, filed April 3, 1940, applied for on behalf of Frtilich et al.
The invention is further illustrated by the following example when taken with the accompanying self-explanatory drawing depicting in section a film according to the present invention.
To 1 kg. silver halide emulsion containing a pyrazolone derivative as color former there is added 1-2 grams of semicarbazide hydrochloride. This mixture is cast onto a support in a manner known per se.
Neither during the manufacturing process nor during prolonged storage could a color-fog be observed on these emulsion layers.
What we claim is 1. In a method of processing photographic colormaterial comprising a support carrying a silver halide emulsion layer containing a color former reactivelwit h the oxidation products of an aromatic amino'developer-to form a dye in situ with the silver image, and an aldehyde hardening agent for the emulsion tending to react Wit1l. said color former to produce color fog, the
improvement which comprises inhibiting the formation of said color fog by contacting said color material with an organic substance reactive with the aldehyde hardening agent and selected from the" class consisting of hydroxyl amines, hydrazines, hydrazo compounds, semicarbazides, naphthalene diamines, and dimethylhydroresorcines.
2. Photographic color material comprising a support carrying a silver halide emulsion'layer containing a color former reactive with the oxi dation products of an aromatic amino developer to form a dye in situ with the silver image, and an aldehyde hardening agent tending to react with said color former to produce color fog, said material also containing an organic substance reactive with the aldehyde hardening agent and selected from the class consisting of hydroxyl amines, hydrazines, hydrazo compounds, semicarbazides, naphthalene diamines, and dimethylhydroresorcines.
3. A photographic material for color forming development comprising a support layer, at least one silver halide emulsion layer containing a color former reactive with the oxidation products of an aromatic amino developer to form a dye in situ with the silver image, at least one intermediate layer, and a backing layer, at least one of said layers containing traces of an aidehyde hardening agent having the tendency to produce color fog with said color former, at least one of said layers containing a compound reactive with the aldehyde hardening agent and selected from the class consisting of hydroxyl amines, hydrazines, hydrazo compounds, semicarbazides, naphthalene diamines, and dimethylhydroresorcines.
4. A photographic material for color forming development comprising a support layer substantially consisting of a paper support and a barium sulfate layer, at least one silver halide gelatin emulsion layer containing a color former reactive with the oxidation products of an aromatic amino developer to form a dye in situ with the silver image, at least one intermediate layer, and a backing layer, said paper support and said emulsion layer containing traces of an aldehyde hardening agent having the tendency to produce color fog with said color former said paper least one of said layers an aldehyde hardening agent tending to react with the color former to produce color fog, and said gelatino silver halide emulsion also containing an organic substance reactive with the aldehyde hardening agent and selected from the class consisting of hydroxyl amines, hydrazines, hydrazo compounds, semi-.- carbazides, naphthalene diamlnes and dimethylhydroresorcines.
'7. Multi-color photographic paper comprising a gelatino silver halide emulsion layer containing a color former reactive with the oxidation products of an aromatic developer to form a dye in situ with the silver image, a barium sulfate layer, and-a paper support for the photographic emulsion and the barium sulfate layer, said photographic material containing in at least one of said layers an aldehyde-hardening agent tending to react with the color former to produce color fog, said barium sulfate layer containing an organic substance reactive with the aldehyde hardening agent and selected from the class consisting of hydroxyl amines, hydrazines, hydrazo support additionally containing a compound reactive with the aldehyde hardening agent and selected from the class consisting of'hydroxyl amines, hydrazines, hydrazo compounds, semicarbazides, naphthalene diamines, and dimethylhydroresorcines.
5. A photographic material for color forming development comprising a support layer substantially consisting of a paper support and a barium sulfate layer, at least one silver halide gelatin emulsion layer containing a color former reactive with the oxidation products of an aromatic amino developer to form a dye in situ with the silver image, at least one intermediate layer and a backing layer, said barium sulfate layer and said emulsion layer containing traces of an aldehyde hardening. agent having the tendency to produce color fog with said color former, .said barium sulfate layer additionally containing a compound reactive with the aldehyde hardening agent and selected from the class consisting of hydroxyl amines, hydrazines, hydrazo compounds, semi-carbazides, naphthalene diamines, and dimethylhydroresorc'ines.
photographic emulsion and said barium sulfate layer, said photographic paper containing in at compounds, semi-carbazides, naphthalene diamines, and dimethylhydroresorcines.
8. A multi-color photographic paper compris-- sulfate layer, at least one of said layers 'containing an aldehyde hardening agent, tending to react with the color former to produce color fog, said paper support containing an organic substance reactive with the aldehyde hardening agent and selected from the class consisting of hydroxyl amines, hydrazines, hydrazo compounds, semi-carbazides, naphthalene diamines, and dimethyldroresorcines.
9. The process as defined in claim 1 wherein the organic substance reactive with the aldehyde hardening agent is a seml-carbazide.
10. The article as defined in claim 2 wherein the organic substance reactive with the aldehyde hardening agent is a semi-carbazide.
11. The article as defined in claim 2 wherein the organic substance reactive with the aldehyde hardening agent is a semi-carbazide and the color former is a pyrazolone.
12. The article as defined in claim 2 wherein the organic substance reactive with the aldehyde hardening agent is semi-carbazidehydrochloride and the color former is a pyrazolone.
FRITZ ALBERS. ALFRED mormrcn. W'ILI-IEIM SCHNEIDER. ERWIN TRABERT.
CERTIFICATE OF CORRECTI ON Patent No. 2,509,192. January 26, 1915.
FRITZ ALBERS, ET AL.
It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 2, sec- .ond column, line 5859, claim 8, for "dimethyldroresorcines" read dimethylhydroresorcines; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.
Signed and sealed this 11mm day of December, A. D. 19%.
Henry Van Arsdalew, (Seal) Acting Commissioner of Patents.
US352402A 1939-07-14 1940-08-13 Process for avoiding color fog on photographic color material Expired - Lifetime US2309492A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DEI0065141 1939-07-14

Publications (1)

Publication Number Publication Date
US2309492A true US2309492A (en) 1943-01-26

Family

ID=7196276

Family Applications (1)

Application Number Title Priority Date Filing Date
US352402A Expired - Lifetime US2309492A (en) 1939-07-14 1940-08-13 Process for avoiding color fog on photographic color material

Country Status (4)

Country Link
US (1) US2309492A (en)
BE (1) BE439613A (en)
FR (1) FR880504A (en)
IT (1) IT384872A (en)

Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2419975A (en) * 1943-08-26 1947-05-06 Eastman Kodak Co Increasing speed and contrast of photographic emulsions
US2419974A (en) * 1943-08-26 1947-05-06 Eastman Kodak Co Silver halide emulsions containing water-insoluble hydrazine derivatives
US2423767A (en) * 1944-02-03 1947-07-08 Ilford Ltd Tone-control agents for silver halide emulsions
US2430254A (en) * 1942-12-23 1947-11-04 Rca Corp Fibrous sheet material for producing dyes thereon by electrolytic oxidation
US2433632A (en) * 1942-12-23 1947-12-30 Rca Corp Fibrous sheet material for the electrolytic formation of azo dye image records thereon
US2435700A (en) * 1942-12-23 1948-02-10 Nellie W Solomon Process of electrolytically producing azo dyes on a fibrous sheet material and the fibrous sheet material for said process
US2440526A (en) * 1942-12-23 1948-04-27 Nellie W Solomon Fibrous sheet material for the electrolytic formation of an azo dyestuff thereon
US2449153A (en) * 1944-04-03 1948-09-14 Urbach Franz Photographic silver bromide emulsion sensitized with cysteine
US2495000A (en) * 1945-02-24 1950-01-17 Gen Aniline & Film Corp Production of azo dyestuff images from n-acyl-n-aryl hydrazine developers
US2571725A (en) * 1946-08-15 1951-10-16 Eastman Kodak Co Eliminating stain in photographic color material
US2591542A (en) * 1948-12-16 1952-04-01 Gen Aniline & Film Corp Hardened photographic film of improved photographic properties
US2642362A (en) * 1949-03-18 1953-06-16 Eastman Kodak Co Light-sensitive baryta-coated photographic paper
US3141771A (en) * 1961-02-01 1964-07-21 Eastman Kodak Co Aldehyde scavengers for photographic silver halide developers
US3168400A (en) * 1961-05-22 1965-02-02 Eastman Kodak Co Rapid processing of photographic color materials
US3174862A (en) * 1959-09-11 1965-03-23 Agfa Ag Process for improving the color reproduction in color photographic material
US3227552A (en) * 1960-05-13 1966-01-04 Eastman Kodak Co Preparation of photographic direct positive color images
US3418132A (en) * 1965-06-01 1968-12-24 Eastman Kodak Co Aldehyde gelatin hardening composition with carbocyclic diones
US4411987A (en) * 1981-11-06 1983-10-25 Fuji Photo Film Co., Ltd. Silver halide color photographic light-sensitive material
EP0338785A2 (en) * 1988-04-21 1989-10-25 EASTMAN KODAK COMPANY (a New Jersey corporation) Photographic element containing scavenger for oxidized developing agent

Cited By (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2430254A (en) * 1942-12-23 1947-11-04 Rca Corp Fibrous sheet material for producing dyes thereon by electrolytic oxidation
US2433632A (en) * 1942-12-23 1947-12-30 Rca Corp Fibrous sheet material for the electrolytic formation of azo dye image records thereon
US2435700A (en) * 1942-12-23 1948-02-10 Nellie W Solomon Process of electrolytically producing azo dyes on a fibrous sheet material and the fibrous sheet material for said process
US2440526A (en) * 1942-12-23 1948-04-27 Nellie W Solomon Fibrous sheet material for the electrolytic formation of an azo dyestuff thereon
US2419975A (en) * 1943-08-26 1947-05-06 Eastman Kodak Co Increasing speed and contrast of photographic emulsions
US2419974A (en) * 1943-08-26 1947-05-06 Eastman Kodak Co Silver halide emulsions containing water-insoluble hydrazine derivatives
US2423767A (en) * 1944-02-03 1947-07-08 Ilford Ltd Tone-control agents for silver halide emulsions
US2449153A (en) * 1944-04-03 1948-09-14 Urbach Franz Photographic silver bromide emulsion sensitized with cysteine
US2495000A (en) * 1945-02-24 1950-01-17 Gen Aniline & Film Corp Production of azo dyestuff images from n-acyl-n-aryl hydrazine developers
US2571725A (en) * 1946-08-15 1951-10-16 Eastman Kodak Co Eliminating stain in photographic color material
US2591542A (en) * 1948-12-16 1952-04-01 Gen Aniline & Film Corp Hardened photographic film of improved photographic properties
US2642362A (en) * 1949-03-18 1953-06-16 Eastman Kodak Co Light-sensitive baryta-coated photographic paper
US3174862A (en) * 1959-09-11 1965-03-23 Agfa Ag Process for improving the color reproduction in color photographic material
US3227552A (en) * 1960-05-13 1966-01-04 Eastman Kodak Co Preparation of photographic direct positive color images
US3141771A (en) * 1961-02-01 1964-07-21 Eastman Kodak Co Aldehyde scavengers for photographic silver halide developers
US3168400A (en) * 1961-05-22 1965-02-02 Eastman Kodak Co Rapid processing of photographic color materials
US3418132A (en) * 1965-06-01 1968-12-24 Eastman Kodak Co Aldehyde gelatin hardening composition with carbocyclic diones
US4411987A (en) * 1981-11-06 1983-10-25 Fuji Photo Film Co., Ltd. Silver halide color photographic light-sensitive material
EP0338785A2 (en) * 1988-04-21 1989-10-25 EASTMAN KODAK COMPANY (a New Jersey corporation) Photographic element containing scavenger for oxidized developing agent
EP0338785A3 (en) * 1988-04-21 1990-01-10 Eastman Kodak Company (A New Jersey Corporation) Photographic element containing scavenger for oxidized developing agent

Also Published As

Publication number Publication date
IT384872A (en)
FR880504A (en) 1943-03-29
BE439613A (en)

Similar Documents

Publication Publication Date Title
US2309492A (en) Process for avoiding color fog on photographic color material
US2108602A (en) Photographic color-forming compounds
US2440110A (en) Stabilized silver halide emulsions
US2394198A (en) Stabilized silver halide emulsions
US2950197A (en) Hardening of gelatin
US2286662A (en) Color photography
JPH0469770B2 (en)
US3168400A (en) Rapid processing of photographic color materials
US3909268A (en) Tetrazolium C-oxy-betaine compounds as antifog agents for silver halide photographic emulsions
US2364017A (en) Production of blue-black toned silver images
US2515121A (en) Process for preventing stains in photographic color material by treatment with basic acids immediately prior to drying
US2579436A (en) Process of inhibiting the degradation of photographic color images
US2933391A (en) Photographic emulsions containing 5-pyrazolone coupler compounds
US2518686A (en) Aldehyde antistain baths for developed color photographic material
US1696830A (en) Light-sensitive silver halide emulsions and process of making the same
US2487446A (en) Process for preventing stains on photographic color material during drying following exposure, bleaching, and fixing treatment
US3910794A (en) Imidazole couplers for two component diazotype systems
US2113330A (en) Color-forming developers
US2279411A (en) Couplers combined with hardening agents
JPS588503B2 (en) color
US2897079A (en) Production of colored photographic images with oxodiazole couplers
US3180734A (en) Light sensitive photographic color element
US3652278A (en) Pre-development process for reducing fog in silver halide photographic materials
US2454001A (en) Control of contrast with aromatic diamine color developers
US4939079A (en) Photographic recording material