US2675318A - Hydroquinone monosulfonate in direct positive photographic developers - Google Patents
Hydroquinone monosulfonate in direct positive photographic developers Download PDFInfo
- Publication number
- US2675318A US2675318A US233774A US23377451A US2675318A US 2675318 A US2675318 A US 2675318A US 233774 A US233774 A US 233774A US 23377451 A US23377451 A US 23377451A US 2675318 A US2675318 A US 2675318A
- Authority
- US
- United States
- Prior art keywords
- emulsion
- direct positive
- hydroquinone
- silver halide
- silver
- 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
Links
- IKQCSJBQLWJEPU-UHFFFAOYSA-N 2,5-dihydroxybenzenesulfonic acid Chemical compound OC1=CC=C(O)C(S(O)(=O)=O)=C1 IKQCSJBQLWJEPU-UHFFFAOYSA-N 0.000 title claims description 6
- 239000000839 emulsion Substances 0.000 claims description 47
- -1 SILVER HALIDE Chemical class 0.000 claims description 18
- 229910052709 silver Inorganic materials 0.000 claims description 14
- 239000004332 silver Substances 0.000 claims description 14
- 238000000034 method Methods 0.000 claims description 10
- QIGBRXMKCJKVMJ-UHFFFAOYSA-N Hydroquinone Chemical class OC1=CC=C(O)C=C1 QIGBRXMKCJKVMJ-UHFFFAOYSA-N 0.000 claims description 7
- OAKJQQAXSVQMHS-UHFFFAOYSA-N Hydrazine Chemical compound NN OAKJQQAXSVQMHS-UHFFFAOYSA-N 0.000 claims description 6
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 claims description 3
- 229910052783 alkali metal Inorganic materials 0.000 claims description 3
- 150000001340 alkali metals Chemical class 0.000 claims 1
- 239000000243 solution Substances 0.000 description 18
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 14
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 9
- ZVNPWFOVUDMGRP-UHFFFAOYSA-N 4-methylaminophenol sulfate Chemical compound OS(O)(=O)=O.CNC1=CC=C(O)C=C1.CNC1=CC=C(O)C=C1 ZVNPWFOVUDMGRP-UHFFFAOYSA-N 0.000 description 6
- IOLCXVTUBQKXJR-UHFFFAOYSA-M potassium bromide Chemical compound [K+].[Br-] IOLCXVTUBQKXJR-UHFFFAOYSA-M 0.000 description 6
- GEHJYWRUCIMESM-UHFFFAOYSA-L sodium sulfite Chemical compound [Na+].[Na+].[O-]S([O-])=O GEHJYWRUCIMESM-UHFFFAOYSA-L 0.000 description 6
- SQGYOTSLMSWVJD-UHFFFAOYSA-N silver(1+) nitrate Chemical compound [Ag+].[O-]N(=O)=O SQGYOTSLMSWVJD-UHFFFAOYSA-N 0.000 description 5
- 150000005208 1,4-dihydroxybenzenes Chemical class 0.000 description 4
- JKFYKCYQEWQPTM-UHFFFAOYSA-N 2-azaniumyl-2-(4-fluorophenyl)acetate Chemical compound OC(=O)C(N)C1=CC=C(F)C=C1 JKFYKCYQEWQPTM-UHFFFAOYSA-N 0.000 description 4
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 4
- 229910021612 Silver iodide Inorganic materials 0.000 description 4
- 229920000159 gelatin Polymers 0.000 description 4
- 235000019322 gelatine Nutrition 0.000 description 4
- NLKNQRATVPKPDG-UHFFFAOYSA-M potassium iodide Chemical compound [K+].[I-] NLKNQRATVPKPDG-UHFFFAOYSA-M 0.000 description 4
- 229940045105 silver iodide Drugs 0.000 description 4
- KICVIQZBYBXLQD-UHFFFAOYSA-M sodium;2,5-dihydroxybenzenesulfonate Chemical compound [Na+].OC1=CC=C(O)C(S([O-])(=O)=O)=C1 KICVIQZBYBXLQD-UHFFFAOYSA-M 0.000 description 4
- 238000007362 Burton trifluoromethylation reaction Methods 0.000 description 3
- 239000001828 Gelatine Substances 0.000 description 3
- 235000010627 Phaseolus vulgaris Nutrition 0.000 description 3
- 244000046052 Phaseolus vulgaris Species 0.000 description 3
- 150000002429 hydrazines Chemical class 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 229940067157 phenylhydrazine Drugs 0.000 description 3
- 150000003839 salts Chemical class 0.000 description 3
- 230000001235 sensitizing effect Effects 0.000 description 3
- ADZWSOLPGZMUMY-UHFFFAOYSA-M silver bromide Chemical compound [Ag]Br ADZWSOLPGZMUMY-UHFFFAOYSA-M 0.000 description 3
- ZUNKMNLKJXRCDM-UHFFFAOYSA-N silver bromoiodide Chemical compound [Ag].IBr ZUNKMNLKJXRCDM-UHFFFAOYSA-N 0.000 description 3
- 235000010265 sodium sulphite Nutrition 0.000 description 3
- LJCWONGJFPCTTL-UHFFFAOYSA-N 4-hydroxyphenylglycine Chemical compound OC(=O)C(N)C1=CC=C(O)C=C1 LJCWONGJFPCTTL-UHFFFAOYSA-N 0.000 description 2
- CPELXLSAUQHCOX-UHFFFAOYSA-M Bromide Chemical compound [Br-] CPELXLSAUQHCOX-UHFFFAOYSA-M 0.000 description 2
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 2
- 229910021529 ammonia Inorganic materials 0.000 description 2
- 239000012964 benzotriazole Substances 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 239000000975 dye Substances 0.000 description 2
- 125000001495 ethyl group Chemical group [H]C([H])([H])C([H])([H])* 0.000 description 2
- XMBWDFGMSWQBCA-UHFFFAOYSA-N hydrogen iodide Chemical compound I XMBWDFGMSWQBCA-UHFFFAOYSA-N 0.000 description 2
- 230000003287 optical effect Effects 0.000 description 2
- GGCZERPQGJTIQP-UHFFFAOYSA-N sodium;9,10-dioxoanthracene-2-sulfonic acid Chemical compound [Na+].C1=CC=C2C(=O)C3=CC(S(=O)(=O)O)=CC=C3C(=O)C2=C1 GGCZERPQGJTIQP-UHFFFAOYSA-N 0.000 description 2
- 238000005406 washing Methods 0.000 description 2
- SWGZHHCRMZDRSN-BTJKTKAUSA-N (Z)-but-2-enedioic acid 1-phenoxypropan-2-ylhydrazine Chemical compound OC(=O)\C=C/C(O)=O.NNC(C)COC1=CC=CC=C1 SWGZHHCRMZDRSN-BTJKTKAUSA-N 0.000 description 1
- 108010010803 Gelatin Proteins 0.000 description 1
- 125000000066 S-methyl group Chemical group [H]C([H])([H])S* 0.000 description 1
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- HOLVRJRSWZOAJU-UHFFFAOYSA-N [Ag].ICl Chemical compound [Ag].ICl HOLVRJRSWZOAJU-UHFFFAOYSA-N 0.000 description 1
- 238000005273 aeration Methods 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- SSQNAPWMQSPZRM-UHFFFAOYSA-N benzene-1,4-diol;sodium Chemical compound [Na].OC1=CC=C(O)C=C1 SSQNAPWMQSPZRM-UHFFFAOYSA-N 0.000 description 1
- QRUDEWIWKLJBPS-UHFFFAOYSA-N benzotriazole Chemical compound C1=CC=C2N[N][N]C2=C1 QRUDEWIWKLJBPS-UHFFFAOYSA-N 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 230000029087 digestion Effects 0.000 description 1
- SYOOJDWKARXQOG-UHFFFAOYSA-L disodium;3,6-dihydroxybenzene-1,2-disulfonate Chemical compound [Na+].[Na+].OC1=CC=C(O)C(S([O-])(=O)=O)=C1S([O-])(=O)=O SYOOJDWKARXQOG-UHFFFAOYSA-L 0.000 description 1
- MQRJBSHKWOFOGF-UHFFFAOYSA-L disodium;carbonate;hydrate Chemical compound O.[Na+].[Na+].[O-]C([O-])=O MQRJBSHKWOFOGF-UHFFFAOYSA-L 0.000 description 1
- 239000008273 gelatin Substances 0.000 description 1
- 235000011852 gelatine desserts Nutrition 0.000 description 1
- 238000005286 illumination Methods 0.000 description 1
- 239000004615 ingredient Substances 0.000 description 1
- 150000002497 iodine compounds Chemical class 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- HKOOXMFOFWEVGF-UHFFFAOYSA-N phenylhydrazine Chemical compound NNC1=CC=CC=C1 HKOOXMFOFWEVGF-UHFFFAOYSA-N 0.000 description 1
- JOVOSQBPPZZESK-UHFFFAOYSA-N phenylhydrazine hydrochloride Chemical compound Cl.NNC1=CC=CC=C1 JOVOSQBPPZZESK-UHFFFAOYSA-N 0.000 description 1
- 229940038531 phenylhydrazine hydrochloride Drugs 0.000 description 1
- VKDSBABHIXQFKH-UHFFFAOYSA-M potassium;4-hydroxy-3-sulfophenolate Chemical compound [K+].OC1=CC=C(O)C(S([O-])(=O)=O)=C1 VKDSBABHIXQFKH-UHFFFAOYSA-M 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 230000005070 ripening Effects 0.000 description 1
- 229910001961 silver nitrate Inorganic materials 0.000 description 1
- 229910000029 sodium carbonate Inorganic materials 0.000 description 1
- AKHNMLFCWUSKQB-UHFFFAOYSA-L sodium thiosulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=S AKHNMLFCWUSKQB-UHFFFAOYSA-L 0.000 description 1
- 235000019345 sodium thiosulphate Nutrition 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- 239000011593 sulfur Substances 0.000 description 1
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 239000010937 tungsten Substances 0.000 description 1
Images
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
- 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
Definitions
- This invention relates to photography and particularly to developers for direct positive photographic processes.
- contrast may be varied in emulsions of the type disclosed in the Fallesen patent and in Davey and Knott U. S. Patent 2,592,250 by the use of developers containing one or more hydroquinone sulfonates, e. g., hydroquinone monosulfonate, but substantially free of unsubstituted hydroquinone.
- the developers preferably also contain N-methyl-p-aminophenol sulfate and one of the hydrazines disclosed in the Ives U. S. Patent 2,588,982, or Bean and Russell U. S. application Serial No. 218,072, filed March 28, 1951, now Patent No. 2,604,400.
- the photographic emulsion used in the process of our invention is a gelatino-silver halide emulsion such as a silver bromide emulsion, a silver bromoiodide emulsion or a silver chloroiodide emulsion. It need not contain optical sensitizing dyes although certain sensitizing dyes may be added to it for the purpose of optical sensitizing or for promoting reversal.
- the emulsion should be undigested or if digested, the digestion should B is heated to 70 C. and A, cold, added to B with constant shaking, digested for 20 minutes at 50 C., and allowed to cool slowly. C is added after being allowed to swell for 20 minutes in water, drained and melted. The emulsion is then set and washed.
- An internal latent image emulsion that is, one which forms the latent image mostly inside the silver halide grains, as described on pages 296 and 297 of Mees The Theory of the Photographic Process, 1942, is especially useful for the process of our invention.
- Most of the internal latent image emulsions are silver bromoiodide emulsions of high iodide content, preferably containing at least 10%20% of iodide.
- Burtons emulsion is an emulsion of this type, having a silver iodide content of approximately 40% of the content of silver halide. It is not absolutely essential, however, for the emulsion to contain silver iodide.
- This emulsion is prepared by first forming in the absence of ammonia and in one or more stages silver salt grains consisting at least partly of a silver salt which is more soluble in water than silver bromide, subsequently converting the grains to silver bromide or silver bromoiodide and if the silver iodide content of the emulsion is less than 6% calculated on the total silver halide, treating such grains with an iodine compound to bring the silver iodide up to at least 6%, ripening preferably in the absence of ammonia and then either washing out some of the soluble salts or washing out the whole of the soluble salts, followed by the addition of solu ble salts such as soluble choride or bromide.
- An example of an emulsion made in this Way is as follows:
- An internal latent image type of silver halide emulsion may be defined as one which, when a test portion is exposed to alight intensity scale for a fixed time between and 1 second, and developed for 4 minutes at 20 C. in the ordinary, "surface developer (Example I), exhibits a maximum density not greater than the maximum density obtained when the same emulsion is equally exposed and developed for 3 minutes at 20 C. in an internal type developer (Example II).
- the maximum density obtained with the surface developer is not greater than the maximum density obtained when the same emulsion is developed in the internal type developer.
- an internal latent image emulsion when developed in an internal type developer (Example II) exhibits a maximum density at least 5, and preferably at least 10', times the maximum density obtained when the same emulsion is exposed in the same way and developed in a surface developer (Example I).
- Our process is carried out by exposing the internal latent image emulsion to an object or image and then placing the exposed emulsion layer directly in a silver halide developing solu tion containing an alkali metal salt of sulfonated hydroquinone, e. g, sodium hydroquinone monosulfonate, potassium hydroquinone monosulfonate, or sodium hydroquinone disulfonate.
- the developing solution should also contain N-methyl-p-aminophenol sulfate, and by varying the cdncentration of this ingredient, direct positive images of varying contrast can be produced.
- the developing solution should also contain one of the hydrazines disclosed in the Ives Patent 2,588,982 or the Bean and Russell U. S.
- an aryl hydrazine such as phenylhydrazine hydrochloride, a-naphthylhydrazine, l-naphthylhydrazine-l-sulfonic acid, p- (fl-methyl sulfonamidoethyl) phenylhydrazine, or p-methyl sulfonamido ethyl hydrazine hydrochloride.
- the developing solution should have a pH of from 10 to 13, the most satisfactory range being from pH 10.5 to pH 11.5.
- the developin solution should contain no unsubstituted hydrcquinone
- Example I p-Hydroxyphenylglycine -Q g 10 Sodium carbonate (crystals) g 100 Water 1201 liter Development time, 4 min. at 20 CL
- An internaltype developer that is, one which develops an image inside the grains of an internal latent image emulsion is the following:
- Example II I-Iydroquinone g.. N-methyl-p-aminophenol sulfate g 15 Sodium sulfite (anhydrous) g 50 Potassium bromide g 10 Sodium hydroxide g 25 Sodium thiosulfate (crystals) g Water to 1 liter Development time, 3 min. at 20 C.
- Example V An emulsion made as described in the Davey and Knott U. S. Patent 2,592,250 was coated on a support, dried and exposed on an intensity scale sensitometer to 3000" K. tungsten illumination and developed for 1 minutes at 75 F. in the developer of Example III. A direct positive image having the characteristic curves shown in A of the drawing was produced.
- a developing solution for direct positive silver halide emulsions comprising N-met hylpaminophenol sulfate, an aryl hydrazine,--and-at Z least one alkali metal hydroquinone sulfonate and substantially free of unsubstituted hydroquinone.
- a developing solution for direct positive silver halide emulsions comprising N-methyl-paminophenol sulfate, p-(fl-methyl sulfonamidoethyl) -phenyl hydrazine and sodium hydroquinone monosulfonate and substantially free of unsubstituted hydroquinone.
- the method of obtaining a direct positive image in a silver halide emulsion layer which comprises exposing to light rays to which the emulsion is sensitive, a silver halide emulsion layer a, test portion of which upon exposure to a light intensity scale for a fixed time between and 1 second and development for 3 minutes at 20 C. in the following internal type developer (II) Water to 1 liter gives a maximum density at least 5 times the maximum density obtained when the equally exposed silver halide emulsion isdeveloped for 4 minutes at 20 C.
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Silver Salt Photography Or Processing Solution Therefor (AREA)
- Photosensitive Polymer And Photoresist Processing (AREA)
Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
BE512294D BE512294A (fr) | 1951-06-27 | ||
US233774A US2675318A (en) | 1951-06-27 | 1951-06-27 | Hydroquinone monosulfonate in direct positive photographic developers |
FR1078936D FR1078936A (fr) | 1951-06-27 | 1952-06-23 | Procédé photographique d'inversion et produits utilisables pour sa mise en oeuvre |
GB16262/52A GB712374A (en) | 1951-06-27 | 1952-06-27 | Improvements in photographic processes |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US233774A US2675318A (en) | 1951-06-27 | 1951-06-27 | Hydroquinone monosulfonate in direct positive photographic developers |
Publications (1)
Publication Number | Publication Date |
---|---|
US2675318A true US2675318A (en) | 1954-04-13 |
Family
ID=22878637
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US233774A Expired - Lifetime US2675318A (en) | 1951-06-27 | 1951-06-27 | Hydroquinone monosulfonate in direct positive photographic developers |
Country Status (4)
Country | Link |
---|---|
US (1) | US2675318A (fr) |
BE (1) | BE512294A (fr) |
FR (1) | FR1078936A (fr) |
GB (1) | GB712374A (fr) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3236652A (en) * | 1963-01-10 | 1966-02-22 | Eastman Kodak Co | Stabilized silver halide emulsions |
US3993490A (en) * | 1974-02-12 | 1976-11-23 | E. I. Du Pont De Nemours And Company | Direct positive photographic elements containing developers |
EP0782041A2 (fr) | 1995-12-27 | 1997-07-02 | Fuji Photo Film Co., Ltd. | Matériau photographique à l'halogénure d'argent sensible à la lumière |
EP0782042A2 (fr) | 1995-12-27 | 1997-07-02 | Fuji Photo Film Co., Ltd. | Composé d'hydrazine et matériau photographique à l'halogénure d'argent le contenant |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2458376A (en) * | 1946-03-14 | 1949-01-04 | Eastman Kodak Co | Photographic developer antioxidants |
US2497875A (en) * | 1947-10-17 | 1950-02-21 | Eastman Kodak Co | Direct positive photographs using aerial fogging developer |
US2497876A (en) * | 1947-05-22 | 1950-02-21 | Eastman Kodak Co | Method of producing direct positive photographic images |
US2563785A (en) * | 1950-04-29 | 1951-08-07 | Eastman Kodak Co | Direct positive photographs from hydrazine-containing developers |
US2572903A (en) * | 1944-06-22 | 1951-10-30 | Gen Aniline & Film Corp | Photographic developer containing thallium salts |
US2604400A (en) * | 1951-03-28 | 1952-07-22 | Eastman Kodak Co | Naphthyl hydrazine sulfonic acids in direct positive photographic processes |
-
0
- BE BE512294D patent/BE512294A/xx unknown
-
1951
- 1951-06-27 US US233774A patent/US2675318A/en not_active Expired - Lifetime
-
1952
- 1952-06-23 FR FR1078936D patent/FR1078936A/fr not_active Expired
- 1952-06-27 GB GB16262/52A patent/GB712374A/en not_active Expired
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2572903A (en) * | 1944-06-22 | 1951-10-30 | Gen Aniline & Film Corp | Photographic developer containing thallium salts |
US2458376A (en) * | 1946-03-14 | 1949-01-04 | Eastman Kodak Co | Photographic developer antioxidants |
US2497876A (en) * | 1947-05-22 | 1950-02-21 | Eastman Kodak Co | Method of producing direct positive photographic images |
US2497875A (en) * | 1947-10-17 | 1950-02-21 | Eastman Kodak Co | Direct positive photographs using aerial fogging developer |
US2563785A (en) * | 1950-04-29 | 1951-08-07 | Eastman Kodak Co | Direct positive photographs from hydrazine-containing developers |
US2604400A (en) * | 1951-03-28 | 1952-07-22 | Eastman Kodak Co | Naphthyl hydrazine sulfonic acids in direct positive photographic processes |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3236652A (en) * | 1963-01-10 | 1966-02-22 | Eastman Kodak Co | Stabilized silver halide emulsions |
US3993490A (en) * | 1974-02-12 | 1976-11-23 | E. I. Du Pont De Nemours And Company | Direct positive photographic elements containing developers |
EP0782041A2 (fr) | 1995-12-27 | 1997-07-02 | Fuji Photo Film Co., Ltd. | Matériau photographique à l'halogénure d'argent sensible à la lumière |
EP0782042A2 (fr) | 1995-12-27 | 1997-07-02 | Fuji Photo Film Co., Ltd. | Composé d'hydrazine et matériau photographique à l'halogénure d'argent le contenant |
Also Published As
Publication number | Publication date |
---|---|
FR1078936A (fr) | 1954-11-24 |
BE512294A (fr) | |
GB712374A (en) | 1954-07-21 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US2588982A (en) | Direct positive photographs using hydrazine in the emulsion | |
US3206313A (en) | Chemically sensitized emulsions having low surface sensitivity and high internal sensitivity | |
US2497875A (en) | Direct positive photographs using aerial fogging developer | |
US2751297A (en) | Photographic emulsion layer containing a 3-pyrazolidone | |
US2563785A (en) | Direct positive photographs from hydrazine-containing developers | |
US3622318A (en) | Photographic materials and processes | |
US3935014A (en) | Direct-positive photographic emulsion containing, unfogged, monodispersed silver halide grains having a layered grain structure of specific silver chloride content | |
US2497917A (en) | Method of producing direct positive photographs having increased density | |
US3957488A (en) | Photographic emulsion containing unfogged, heterodisperse layered silver halide grains having a prodominantly bromide core and total chloride content less than 30 mole percent | |
US4839268A (en) | Silver halide color reversal photosensitive material | |
US4604339A (en) | Method of developing silver halide photographic light-sensitive material | |
US3708298A (en) | Method of producing direct positive images with photographic silver halide material containing compound releasing iodide ions | |
US2675318A (en) | Hydroquinone monosulfonate in direct positive photographic developers | |
EP0454149B1 (fr) | Matériau photographique à l'halogénne d'argent | |
US4263396A (en) | Direct-positive photographic material | |
US3149970A (en) | Production of photographic silver images by physical development | |
US2456953A (en) | Photographic reversal processes | |
GB1565825A (en) | Process for forming positive images | |
US2685514A (en) | Direct positive photographic development process | |
US3353957A (en) | Photographic process | |
US2566180A (en) | Direct postive photogrpahic color process | |
US3591385A (en) | Silver halide emulsions sensitized with a combination of sulfur and selenium for color photography | |
US3637388A (en) | Process for the photographic production of equidensities | |
US3565620A (en) | Photographic processing liquids and method of producing photographic images | |
US2490758A (en) | Fuchsone dyes in a direct positive photographic process |