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
  • 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
  • G03C7/392—Additives
  • G03C7/39208—Organic compounds
  • G03C7/39212—Carbocyclic
  • G03C7/39216—Carbocyclic with OH groups

Definitions

• This invention relates to color photography and particularly to a method for preventing the formation of color fog or stain in photographic emulsions.
• color-forming or coupler compounds combine with the development product of aromatic amino photographic developers to produce dyes.
• the color formers or couplers may be added directly to the emulsion layers or may be incorporated in the developing solution as described in Fischer U. S. Patent No. 1,102,028, granted June 30, 1914, or they may be incorporated in a waterpermeable medium which is insoluble in the carrier for the sensitive silver salt as described in Mannes and Godowsky U. S. Patent 2,304,940, December 15, 1942, and Jelley and Vittum U. S. Patent 2,322,027, granted June 15, 1943.
• a difliculty frequently encountered in these processes is the formation of color fog or stain.
• dye fog is frequently formed in the emulsion layer. This is because the developing agent has been oxidized to some extent by the action of the air and the oxidized developer tends to couple with the color-forming compound at places in the photographic material where no silver image is produced. It is well known that in these processes the dye should beformed only where the silver halide is reduced to metallic silver, thereby oxidizing the developing agent to a form which couples with the color former. Once the developing agent is oxidized, it couples immediately with the color former whether a photographic image is present or not.
• Aerial oxidation of the developer or oxidation by means other than the photographic image therefore converts the developer to a form which will immediately react with the color former to produce a color fog on stain.
• This effect is especially noticeable in materials having couplers incorporated in the sensitive layer since there is no coupler in the developing solution to react with any developing agent which is oxidized by the action of the air. Fog or stain arising from these causes is not readily controlled by the same procedures used to control silver fog.
• a further object is to provide antistain agents which are easily compatible with and non-difiusing in the colloid of the photographic layer in which they are incorporated.
• a further object is to provide antistain agents which are non-diffusing in the photographic layer and which are strong enough reducing agents to react rapidly with oxidized color de- 5 veloper.
• a further object is to provide antistain agents which do not form highly colored oxidation products when the material containing them is put through an oxidizing bath.
• This compound was prepared by demethylating 1,1- methylene bis(2,5-dimethoxy-4-octadecylbenzene) with AlC13 in boiling dry benzene.
• Aluminum chloride 20 g. (fine powder) g. of the dimethoxy intermediate, and 200 ml. of dry benzene were refluxed on a steam bath with eflective mechanical stirring for 20 hours.
• the cooled reaction mixture was poured into 1500 ml. of cold methyl alcohol, and the solid obtained was crystallized twice from ethyl acetate, using carbon decolorizing the first time. There was obtained 5.5 g. of colorless material (going pink on standing), having a melting point of 190-191 C.
• This compound was prepared by the method given for 2,2-isobutylidene bis(5-tert-butyl-4-methoxyphenol) substituting 4-rnethoxyphenol for 2-tert-butyl-4-methoxyphenol.
• This compound was prepared by the method given for 2,2-methylene bis(5-tert-butyl-4-methoxyphenol), substituting isobutyraldehyde for formaldehyde.
• the product is a white crystal line material melting at 181.5- 183.5 C.
• the 4,4'-bis(2,5-dihydroxybenzalamino)diphenyl prepared above was reduced in dioxane solution, using Raney nickel as a catalyst and 40-50 pounds of hydrogen pressure at 60-65 C.
• the catalyst was removed from the hot solution by filtration and the solution cooled.
• the product formed was filtered, washed with a small volume of fresh dioxane, and crystallized twice from the same solvent.
• the (2,5-dihydroxybenzyl)benzidine was obtained almost colorless but turned light brown in the open air. It melts at 198-200 C.
• antistain agents of our invention are useful, in general, with emulsions containing couplers incorporated in the manner described in Mannes and Godowsky U. S. Patent 2,304,940 or Jelley and Vittum U. S. Patent 2,322,027.
• Couplers such as those described in Weissberger U. S. Patent 2,298,443 and Salminen and Weissberger U. S. Patent 2,423,730, when incorporated in this way, produce dyes upon color development which are prone to fading by the action of visible or ultraviolet light, when known antistain agents such as 2,5-di-tert. octyl hydroquinone are used in the emulsion layer. These are the yellow and cyan dyes.
• the magenta dyes such as those formed from couplers described in Loria, Weissberger and Vittum U. S. Patent 2,600,788 are relatively little affected by the known antistain agents upon the action of light.
• a quantity of the antistain agent the molar equivalent of 0.05 g. of 2,5-di-tert. octyl hydroquinone was dissolved with 0.5 g. of coupler in 1.5 cc. of dibutylphthalate.
• the resulting mixture was passed through a colloid mill three times, and to the resulting dispersion, 32 cc. of a gelatino-silver halide emulsion were added, and the mixture blended and coated on a film support so that the antistain agent was equivalent to 5 mg. per square foot of 2,5-di-tert. octyl hydroquinone.
• Two check coatings were made: One containing no antistain agent, and one containing 5 mg. per square foot of 2,5-di-tert. octyl hydroquinone.
• the film strips were exposed on a Ib sensitorneter using a silver wedge varying in density from 0 to 3. They were then developed 10 minutes at 68 F. in the following developer:
• Compounds 4, and 7 caused no more fading of the cyan dye than the check coating without antistain agent, and compounds 1, 6 and 7 caused even less fading of the yellow dye than the check coating free of antistain agent, that is, these cornpounds caused some increase in density of yellow dye as well as improving antistain properties.
• Another compound useful as an anti-stain agent in photographic emulsions is 2-p-cyanophenyl-2-imidazoline.
• the antistain agents of our invention may also he used in non-sensitive overcoating or filter layers, such as a colloidal silver interlayer of multilayer photographic material.
• the antistain agents of our invention are used in the emulsion or other layer in quantities ranging from 0.07 gram to 4.3 grams per liter of emulsion or gelatin solution. These values are, however, merely illustrative.
• the antistain agents of our invention may be incorporated in a processing solution such as a prebath, first developer bath, or color-forming developer used with color film which is developed with a primary aromatic amino developing agent.
• Our materials are particularly useful with color-forming emulsions coated on paper supports where it is espe cially important to reduce the minimum or fog densities. This applies both to negative developed paper and to reversal paper as well as to transparency materials.
• a color-forming photographic emulsion having reduced fogging tendency comprising a silver halide emulsion having incorporated therein a non-diffusing coupler compound capable of coupling with the oxidation product of a primary aromatic amino developing agent and as an antistain agent a bihydroquinone having the formula (BR OR where R is selected from the class consisting of hydrogen and a methyl radical, R is selected from the class consisting of hydrogen and a methyl radical, X is selected from the class consisting of hydrogen and amino group and an alkyl group having from 1 to 18 carbon atoms, and Z is selected from the class consisting of methylene, isobutylene and N,N'-dimethylenebenzidine groups and a single chemical bond.
• a color-forming photographic emulsion having reduced fogging tendency comprising a silver halide emulsion having incorporated therein a non-difiusing coupler compound capable of coupling with the oxidation prodduct of a primary aromatic amino developing agent and as an antistain agent a bihydroquinone having the formula (I)H OH OH OH in which R is an alkyl group of from 1 to 18 carbon atoms.
• a color-forming photographic emulsion having reduced fogging tendency comprising a silver halide emulsion having incorporated therein a non-diffusing coupler compound capable of coupling with the oxidation product of a primary aromatic amino developing agent and as an antistain agent a bihydroquinone having the formula CH; OCH:
• R is an alkyl group of from 1 to 18 carbon atoms.
• a color-forming photographic emulsion having reduced fogging tendency comprising a silver halide emulsion having incorporated therein a non-diffusing coupler compound capable of coupling with the oxidation product of a primary aromatic amino developing agent and as an antistain agent a bihydroquinone.
• a color-forming photographic emulsion having reduced fogging tendency comprising a silver halide emulsion having incorporated therein a non-diffusing coupler compound capable of coupling with the oxidation product of a primary aromatic amino developing agent and as an antistain agent 2,2-methylene bis(5-tert. butyl-4-methoxyphenol.
• a color-forming photographic emulsion having reduced fogging tendency comprising a. silver halide emulsion having incorporated therein a non-ditfusing coupler compound capable of coupling with the oxidation prodnot of a primary aromatic amino developing agent and as an antistain agent 2,2-methylene bis-S-n-octyl hydroqumone.
• a color-forming photographic emulsion having reduced fogging tendency comprising a silver halide emulsion having incorporated therein a non-diffusing coupler compound capable of coupling with the oxidation product of a primary aromatic amino developing agent and as an antistain agent 1,1'-methylene bis(2,S-dimethoxy-4- octadecylbenzene).

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• Physics & Mathematics (AREA)
• Spectroscopy & Molecular Physics (AREA)
• General Physics & Mathematics (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

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Citations (2)

• 0
  • US US2735765D patent/US2735765A/en not_active Expired - Lifetime
  • BE BE529274D patent/BE529274A/xx unknown
• 1954
  • 1954-06-02 GB GB16321/54A patent/GB752148A/en not_active Expired
  • 1954-06-02 FR FR1110296D patent/FR1110296A/fr not_active Expired

Patent Citations (2)

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