US2712995A - Process for the direct production of positive photographic images - Google Patents

Process for the direct production of positive photographic images Download PDF

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Publication number
US2712995A
US2712995A US109073A US10907349A US2712995A US 2712995 A US2712995 A US 2712995A US 109073 A US109073 A US 109073A US 10907349 A US10907349 A US 10907349A US 2712995 A US2712995 A US 2712995A
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United States
Prior art keywords
silver
emulsion
silver salt
developable
light
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
US109073A
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English (en)
Inventor
Edith Weyde
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.)
Agfa Gevaert NV
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Agfa AG
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Filing date
Publication date
Application filed by Agfa AG filed Critical Agfa AG
Priority to US463318A priority Critical patent/US2875052A/en
Application granted granted Critical
Publication of US2712995A publication Critical patent/US2712995A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
    • G03C5/00—Photographic processes or agents therefor; Regeneration of such processing agents
    • G03C5/26—Processes using silver-salt-containing photosensitive materials or agents therefor
    • G03C5/50—Reversal development; Contact processes
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
    • G03C1/00—Photosensitive materials
    • G03C1/005—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein
    • G03C1/485—Direct positive emulsions
    • G03C1/48538—Direct positive emulsions non-prefogged, i.e. fogged after imagewise exposure
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
    • G03C7/00—Multicolour photographic processes or agents therefor; Regeneration of such processing agents; Photosensitive materials for multicolour processes
    • G03C7/30—Colour processes using colour-coupling substances; Materials therefor; Preparing or processing such materials
    • G03C7/3022—Materials with specific emulsion characteristics, e.g. thickness of the layers, silver content, shape of AgX grains
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S430/00—Radiation imagery chemistry: process, composition, or product thereof
    • Y10S430/156—Precursor compound
    • Y10S430/158—Development inhibitor releaser, DIR

Definitions

  • This invention relates to a process for the direct pro-- duction of positive photographic images and to photographic material used for such a process.
  • Silver bromide at the nonexposed areas is not reduced by the developer. No bromide ions are formed at these areas, so that reduction of the silver chloride proceeds smoothly. At the exposed areas, therefore, only as much silver is formed as corresponds to the reduced bromide; as only very small amounts of silver are concerned, slight blackening only which is scarcely visible is produced, i. e. these areas after processing are practically white if the light-sensitive layer was cast onto paper, or they are transparent if the layer was cast onto a transparent base. At the non-exposed areas, however, silver chloride representing the chief constituent of the layers is reduced, so that these areas show a very deep blackening. So the exposed areas of these layers remain light whereas the non-exposed ones become dark, i. e.
  • a direct positive image of the object is obtained by one process.
  • the developed images In order to remove the non-developed silver halide, the developed images have still to be fixed, washed and dried. it is also feasible to modify the process in such a manner that negative silver is removed by using known reducers so that positive silver only is left; This method allows one to obtain direct positives with excellent whites.
  • the proportion of silver chloride to silver bromide depends on the kind of emulsions used and lies in the range of between 0.1-10 grams of silver bromide to 100 grams of silver chloride.
  • the preparation of these emulsion layers can also be performed in such a manner that Z,'ZlZ,995 Patented July 12, 1955 by the addition of small amounts of potassium bromide or potassium iodide to a silver chloride emulsion such direct positives yielding layers are obtained.
  • the process is not limited to mixtures of silver chloride and silver bromide.
  • silver chloride As low sensitive silver salts, besides silver chloride, also other silver salts, such as silver oxalate, silver stearate, silver ferrocyanide etc., can be used, in which case silver chloride may find application as the higher sensitive component.
  • higher sensitive silver salts besides silver bromide, also silver iodide may be used. It is an essential feature of the new process that the emulsion used in a small amount exhibits a higher sensitivity to light and a lower solubility in the photographic developers used than the less sensitive component. The process can also be modified in such a maner that the less sensitive and higher sensitive components of the mixture consists of mixtures of silver salt emulsions of different gradations.
  • composition of the developer has a considerable influence on the aforesaid process.
  • These solutions are to develop the higher sensitive emulsion before the silver chloride is dissolved and reduced.
  • the same chemicals are generally used which find application for the usual photographic processes, however, without potassium bromide that, for instance, for the silver chloride-silver bromide system can be replaced by sodium chloride.
  • a silver halide solvent for instance, sodium sulfite
  • the silver halide dissolving effect of alkaline sulfite solutions can be increased by the addition of known compounds, for instance, sodium thiosulfate, organic amines etc.
  • the developers employed for linegrain development for instance, p-phenylene diamine and derivatives thereof, possess a sufficiently strong dissolving power of silver chloride and other silver salts so that when using such substances the addition of further silver halide solvents can sometimes be dispensed with.
  • the process for the production of direct positive images according to the present invention shows the ad vantage that processing can be performed in the same way as in the case of a usual negative process without any additional processing steps. If the developer is appropriately composed development proceeds extraordinarily fast that being of advantage, for instance, for automatic, photographic processes. The fact that the silver separated from the dissolved silver chloride is highly fine grained and opaque allows one to produce especially thin reverse layers with a very small amount of silver.
  • V new process is also of great importance for X-ray photography.
  • the sensitivity of the aforesaid reactions is extraordinarily high so that already such actions of light as cause only a scarcely visible blackening upon the usual negative layers yield a distinct positive.
  • Silver images obtained according to the present invention may be subjected to any after-treatment known in photography, for instance, intensification, reduction, toning etc. They may also be used for the contact hardening process and other processes known in the art. It is also feasible to modify the process in such a manner that the ditferently sensitive emulsions are cast in separate layers and the multilayer materials are worked up into direct positives by means of the above described developers.
  • Example 1 To a silver chloride emulsion prepared according to known methods are added per litre cc. of a silver bromide emulsion the sensitivity of which being about twice or three times as high as that of the silver chloride emulsion, and 0.1 gram of colloidal silver. The mixture of emulsions is cast as usual onto paper, film or glass, the silver content of the layer amounting to about 1 gram of silver per square meter. After exposure de velopment is performed in the following solution:
  • Example 2 To a silver chloride emulsion prepared according to known processing methods are added per litre cc. of a silverbromide emulsion the sensitivity of which being a hundred times higher than that of the silver chloride emulsion, and 0.3 gram of colloidal gold. The mixture of these emulsions is applied in such a thin layer that the silver coating amounts to about 0.5 gram per square meter only. These layers can be hardened by adding formalin or other known substances and coated with a protective layer of gelatin to which, ifdesired, some colloidal silver is added. Development of this layer is carried out in the following solution:
  • Example 3 To a silver chlorideemulsion of very low speed produced according to known recipes are added 500 cc. of a silver chloride-bromide emulsion of low sensitivity which has orthochromatically been sensitized with known dyestufls, and 0.1 gram of colloidal silver. This emulsion is applied to paper as usual and developing is carried out in the following solution:
  • Example 4 Water cc 1000 p-Phenylenediamine "grams 3 Soda do 5 Sodium sulfite anhydrous do 1 Temperature C 18 Developing time about 24 minutes.
  • Example 5 To 1000 parts of an emulsion of silver ferrocyanide obtained by precipitating a silver nitrate solution with an equivalent amount of potassium ferrocyanide in the presence of gelatin, which exhibits only a very low light sensitivity, are added per litre 20. cc. of a silver chloride emulsion and 0.3 gram of colloidal silver. These layers directly yield a positive on developing in the following solution:
  • the present invention for the production of direct positive images is not only suited for the processing methods as described in the Examples l-6 but may generally be employed wherever the production of photographic positives or duplicate-negatives is required.
  • gelatin has been used as a binder
  • the new process has proved to be especially suitable for the direct production of photographic positive images when using other binding agents than gelatin. It is known that high sensitive silver bromide emulsions cannot easily be obtained in other binding agents other than gelatin, for instance, in synthetic high molecular products. On the other hand, however, it is comparatively easy to produce silver chloride emulsions or other silver salt emulsions of comparatively low sensitivity by means of such binding agents.
  • a high sensitive silver bromide emulsion prepared as known in the art by means of gelatin as binding agent can be added to a silver chloride emulsion precipitated in any synthetic high molecular compound which is suited for photographic processes, for instance, sericose, polyvinyl alcohol etc.
  • the gelatin containing emulsion is preferably diluted with water or with another solvent, for instance, acetone-water-mixture.
  • Such layers give sensitivities which are essentially higher than those of the hitherto known emulsions on the base of the non-gelatinous binding agent. If emulsions of lower sensitivity are to be obtained it may be of advantage to precipitate also the higher sensitive emulsions, for instance, the silver bromide emulsion in another binding agent.
  • the following example serves for illustrating this process:
  • emulsions are cast in the usual manner in superposed layers, interposing a yellow filter between the upper, only blue-sensitive layer and the lower greenand red-sensitive layers.
  • these layers are treated in a developer containing, for instance, p-phenylene diamine or its derivatives which, with the color couplers contained in the layers, yields a dyestuff.
  • p-phenylene diamine or its derivatives which, with the color couplers contained in the layers, yields a dyestuff.
  • These substances have the property to dissolve silver chloride to a considerable extent so that only very small amounts of sodium sulfite need to be added to these developers in order to initiate a direct positive development.
  • the color-forming developer reduces the exposed silver bromide, bromide ions being set free thereby.
  • the weak negative resulting from the silver bromide consists of silver only and contains no dyestulf.
  • reduction of silver chloride which is present in much bigger quantities is essentially due to the color-forming developer the oxidation product of'which gives the dyestuffs desired with the color couplers.
  • After developing and intermediately Washing the small amounts of negative silver and the larger amounts of silver formed by the reduction of silver chlorideare dissolved by means of known products, for instance, potassium ferricyanide or converted into silver salt which are removed by subsequent fixations.
  • the process is suited for the production of high sensitive, negative as well as positive photographic material. The following example shall further illustrate this process.
  • Example 9 To a silver chloride emulsion prepared as known in the art are added per litre 0.1 gram of colloidal silver and 12 cc. of'a higher sensitive silver bromide emulsion which is sensitized with known dyestuffs for the redor green-sensitive layer respectively.
  • CHa-N- 11 a5 SOsH is first coated onto paper, glass or film. Upon this layer there is coated the corresponding green-sensitive emulsion mixture to which are added as a purple color coupler per litre 20 grams of a compound of the following formula:
  • H2C-CC11H35 O L N
  • salt developing solution containing as solvent an agent 7 which has a higher dissolving power for the lower than for the higher light sensitive silver salt and containing salts having the same anions as those of said higher light sensitive silver salt at most in such a quantity that the reduction of said spontaneously developable silver 'salt emulsion is not prevented until the developing solution forms an extremely faint negative image in the silver halide emulsion, and forms a conspicuous positive image in the spontaneously developable emulsion, the non-metallic by-products from the faint negative image effectively inhibiting the spontaneous development of a conspicuous positive image in the spontaneously developable emulsion in those areas having the negative image whereby a conspicuous direct positive image is developed.
  • the spontaneously developable silver salt emulsion contains substances selected from the group of reduction nuclei and substances forming reduction nuclei with dissolved silver salts.
  • the silver salts of the spontaneously developable emulsion consist mainly of silver chloride and those of the light sensitive emulsion mainly of silver bromide.
  • reduction nuclei are substances selected from at least one of the group of colloidal noble metals and noble metal compounds diflicultly soluble in water.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Silver Salt Photography Or Processing Solution Therefor (AREA)
US109073A 1949-07-04 1949-08-06 Process for the direct production of positive photographic images Expired - Lifetime US2712995A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US463318A US2875052A (en) 1949-08-06 1954-10-19 Photographic material for the direct production of positive photographic images

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CH690997X 1949-07-04

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US2712995A true US2712995A (en) 1955-07-12

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US (1) US2712995A (de)
CH (1) CH278309A (de)
FR (1) FR993337A (de)
GB (1) GB690997A (de)

Cited By (24)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2834676A (en) * 1955-07-19 1958-05-13 Sperry Rand Corp Photographic diffusion transfer process for producing multiple direct positive copies
US2861885A (en) * 1954-11-04 1958-11-25 Polaroid Corp Photographic processes and products
US2872433A (en) * 1955-12-27 1959-02-03 Gen Aniline & Film Corp Stabilization of polymeric n-vinyl pyrrolidones with sulfurous acid or alkali metal salts thereof
US2882253A (en) * 1955-11-16 1959-04-14 Dow Chemical Co Method for stabilizing polyvinylpyrrolidone and compositions thereby obtained
US2937086A (en) * 1955-07-26 1960-05-17 Eastman Kodak Co Multilayer reversal color material
US2968554A (en) * 1954-08-09 1961-01-17 Polaroid Corp Photographic transfer processes for forming multicolor dye images and photographic products for carrying out the same
US2979405A (en) * 1956-06-22 1961-04-11 Gevaert Photo Prod Nv Light-sensitive photographic element containing a 1-hydroxy-2-naphthoic acid anilidecolor coupler
US2982650A (en) * 1955-07-22 1961-05-02 Polaroid Corp Photographic processes and products
US2995444A (en) * 1957-09-26 1961-08-08 Gen Aniline & Film Corp Stabilization of photographic emulsions sensitized with alkylene oxide polymers
US3043697A (en) * 1958-08-27 1962-07-10 Du Pont Photographic gelatin-n-vinyllactam silver halide emulsions containing phenolic antifoggants
US3044873A (en) * 1958-12-17 1962-07-17 Polaroid Corp Photographic products and processes
US3050391A (en) * 1957-12-30 1962-08-21 Gen Aniline & Film Corp Photographic film with fine grain silver chloride underlayer
US3072480A (en) * 1959-04-10 1963-01-08 Eastman Kodak Co Photographic diffusion transfer process
US3140179A (en) * 1959-10-22 1964-07-07 Eastman Kodak Co Photographic element having increased speed and contrast
US3148062A (en) * 1959-04-06 1964-09-08 Eastman Kodak Co Photographic elements and processes using splittable couplers
US3149970A (en) * 1959-01-10 1964-09-22 Agfa Ag Production of photographic silver images by physical development
US3155510A (en) * 1960-07-26 1964-11-03 Agfa Ag Diffusion-resistant organic resin-coupler reaction products for photographic gelatin ayers
US3183087A (en) * 1961-03-27 1965-05-11 Agfa Ag Color reversal development process utilizing a preliminary development bath free of bromide ions
US3227551A (en) * 1959-04-06 1966-01-04 Eastman Kodak Co Photographic color reproduction process and element
US3536488A (en) * 1968-06-13 1970-10-27 Polaroid Corp Multicolor screen-carrying element in additive color photographic processes
DE2036213A1 (en) * 1970-07-21 1972-01-27 Polaroid Corp., Cambridge, Mass. (V.StA.) Additive colour photographic material - with silver mixed halide emulsion contg pptn nuclei on multicoloured screen
US3933494A (en) * 1972-11-15 1976-01-20 Minnesota Mining And Manufacturing Company Method for obtaining a color contrast photographic image by color development and silver salt diffusion transfer processing of one photographic element
US4047956A (en) * 1975-11-17 1977-09-13 E. I. Du Pont De Nemours And Company Low coating weight silver halide element and process
FR2454121A1 (fr) * 1979-04-13 1980-11-07 Konishiroku Photo Ind Procede et materiau photographique a l'halogenure d'argent pour l'obtention d'une image negative

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE539322A (de) * 1954-06-29

Citations (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1454209A (en) * 1922-01-13 1923-05-08 Eastman Kodak Co Self-toning photographic emulsion
US1897866A (en) * 1931-08-25 1933-02-14 Eastman Kodak Co Color photographic process
US2001951A (en) * 1933-03-22 1935-05-21 Ilford Ltd Photographic printing emulsion and its production
US2005837A (en) * 1931-07-07 1935-06-25 Agfa Ansco Corp Manufacture of photographic emulsions
GB446172A (en) * 1934-10-11 1936-04-14 Geoffrey Bond Harrison Improvements in or relating to photographic reversal processes
GB494088A (en) * 1937-03-18 1938-10-18 Frank Forster Renwick Improvements in or relating to photographic printing processes and materials
US2186852A (en) * 1936-12-18 1940-01-09 Agfa Ansco Corp Photographic silver halide emulsions
US2191502A (en) * 1937-01-22 1940-02-27 Pont Film Mfg Company Du Multicolor film and process
FR873507A (fr) * 1939-11-02 1942-07-10 Gevaert Photo Prod Nv Procédé pour l'obtention d'images au moyen d'halogénure d'argent
US2352014A (en) * 1941-07-21 1944-06-20 Rott Andre Photomechanical printing process and printing material for carrying out the same
US2358169A (en) * 1941-03-14 1944-09-12 Eastman Kodak Co Photographic printing material
GB580173A (en) * 1943-03-15 1946-08-29 Kodak Ltd Improvements in or relating to photographic processes
US2456953A (en) * 1942-02-09 1948-12-21 Eastman Kodak Co Photographic reversal processes
US2456954A (en) * 1947-08-01 1948-12-21 Eastman Kodak Co Photographic reversal processes
US2496940A (en) * 1948-10-21 1950-02-07 Eastman Kodak Co Mixed grain photographic process
US2497875A (en) * 1947-10-17 1950-02-21 Eastman Kodak Co Direct positive photographs using aerial fogging developer

Patent Citations (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1454209A (en) * 1922-01-13 1923-05-08 Eastman Kodak Co Self-toning photographic emulsion
US2005837A (en) * 1931-07-07 1935-06-25 Agfa Ansco Corp Manufacture of photographic emulsions
US1897866A (en) * 1931-08-25 1933-02-14 Eastman Kodak Co Color photographic process
US2001951A (en) * 1933-03-22 1935-05-21 Ilford Ltd Photographic printing emulsion and its production
GB446172A (en) * 1934-10-11 1936-04-14 Geoffrey Bond Harrison Improvements in or relating to photographic reversal processes
US2186852A (en) * 1936-12-18 1940-01-09 Agfa Ansco Corp Photographic silver halide emulsions
US2191502A (en) * 1937-01-22 1940-02-27 Pont Film Mfg Company Du Multicolor film and process
GB494088A (en) * 1937-03-18 1938-10-18 Frank Forster Renwick Improvements in or relating to photographic printing processes and materials
FR873507A (fr) * 1939-11-02 1942-07-10 Gevaert Photo Prod Nv Procédé pour l'obtention d'images au moyen d'halogénure d'argent
FR53513E (fr) * 1939-11-02 1946-03-04 Gevaert Photo Prod Nv Procédé pour l'obtention d'images au moyen d'halogénure d'argent
US2358169A (en) * 1941-03-14 1944-09-12 Eastman Kodak Co Photographic printing material
US2352014A (en) * 1941-07-21 1944-06-20 Rott Andre Photomechanical printing process and printing material for carrying out the same
US2456953A (en) * 1942-02-09 1948-12-21 Eastman Kodak Co Photographic reversal processes
GB580173A (en) * 1943-03-15 1946-08-29 Kodak Ltd Improvements in or relating to photographic processes
US2456954A (en) * 1947-08-01 1948-12-21 Eastman Kodak Co Photographic reversal processes
US2497875A (en) * 1947-10-17 1950-02-21 Eastman Kodak Co Direct positive photographs using aerial fogging developer
US2496940A (en) * 1948-10-21 1950-02-07 Eastman Kodak Co Mixed grain photographic process

Cited By (24)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2968554A (en) * 1954-08-09 1961-01-17 Polaroid Corp Photographic transfer processes for forming multicolor dye images and photographic products for carrying out the same
US2861885A (en) * 1954-11-04 1958-11-25 Polaroid Corp Photographic processes and products
US2834676A (en) * 1955-07-19 1958-05-13 Sperry Rand Corp Photographic diffusion transfer process for producing multiple direct positive copies
US2982650A (en) * 1955-07-22 1961-05-02 Polaroid Corp Photographic processes and products
US2937086A (en) * 1955-07-26 1960-05-17 Eastman Kodak Co Multilayer reversal color material
US2882253A (en) * 1955-11-16 1959-04-14 Dow Chemical Co Method for stabilizing polyvinylpyrrolidone and compositions thereby obtained
US2872433A (en) * 1955-12-27 1959-02-03 Gen Aniline & Film Corp Stabilization of polymeric n-vinyl pyrrolidones with sulfurous acid or alkali metal salts thereof
US2979405A (en) * 1956-06-22 1961-04-11 Gevaert Photo Prod Nv Light-sensitive photographic element containing a 1-hydroxy-2-naphthoic acid anilidecolor coupler
US2995444A (en) * 1957-09-26 1961-08-08 Gen Aniline & Film Corp Stabilization of photographic emulsions sensitized with alkylene oxide polymers
US3050391A (en) * 1957-12-30 1962-08-21 Gen Aniline & Film Corp Photographic film with fine grain silver chloride underlayer
US3043697A (en) * 1958-08-27 1962-07-10 Du Pont Photographic gelatin-n-vinyllactam silver halide emulsions containing phenolic antifoggants
US3044873A (en) * 1958-12-17 1962-07-17 Polaroid Corp Photographic products and processes
US3149970A (en) * 1959-01-10 1964-09-22 Agfa Ag Production of photographic silver images by physical development
US3227551A (en) * 1959-04-06 1966-01-04 Eastman Kodak Co Photographic color reproduction process and element
US3148062A (en) * 1959-04-06 1964-09-08 Eastman Kodak Co Photographic elements and processes using splittable couplers
US3072480A (en) * 1959-04-10 1963-01-08 Eastman Kodak Co Photographic diffusion transfer process
US3140179A (en) * 1959-10-22 1964-07-07 Eastman Kodak Co Photographic element having increased speed and contrast
US3155510A (en) * 1960-07-26 1964-11-03 Agfa Ag Diffusion-resistant organic resin-coupler reaction products for photographic gelatin ayers
US3183087A (en) * 1961-03-27 1965-05-11 Agfa Ag Color reversal development process utilizing a preliminary development bath free of bromide ions
US3536488A (en) * 1968-06-13 1970-10-27 Polaroid Corp Multicolor screen-carrying element in additive color photographic processes
DE2036213A1 (en) * 1970-07-21 1972-01-27 Polaroid Corp., Cambridge, Mass. (V.StA.) Additive colour photographic material - with silver mixed halide emulsion contg pptn nuclei on multicoloured screen
US3933494A (en) * 1972-11-15 1976-01-20 Minnesota Mining And Manufacturing Company Method for obtaining a color contrast photographic image by color development and silver salt diffusion transfer processing of one photographic element
US4047956A (en) * 1975-11-17 1977-09-13 E. I. Du Pont De Nemours And Company Low coating weight silver halide element and process
FR2454121A1 (fr) * 1979-04-13 1980-11-07 Konishiroku Photo Ind Procede et materiau photographique a l'halogenure d'argent pour l'obtention d'une image negative

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Publication number Publication date
GB690997A (en) 1953-05-06
FR993337A (fr) 1951-10-30
CH278309A (de) 1951-10-15

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