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
  • G03C5/29—Development processes or agents therefor
  • G03C5/30—Developers
• • 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
  • G03C8/00—Diffusion transfer processes or agents therefor; Photosensitive materials for such processes
  • G03C8/02—Photosensitive materials characterised by the image-forming section
  • G03C8/04—Photosensitive materials characterised by the image-forming section the substances transferred by diffusion consisting of inorganic or organo-metallic compounds derived from photosensitive noble metals
  • G03C8/06—Silver salt diffusion transfer

Definitions

• a primary object of this invention is to provide novel silver halide developing agents, and products, compositions and processes employing said novel silver halide developing agents, for the development of exposed silver halide emulsions.
• a further object of this invention is to provide novel silver halide developing agents particularly useful in diffusion transfer processes.
• the invention accordingly comprises processes involving the several steps and the relation and order of one or more of such steps with respect to each of the others,
• Ascorbic acid has long been known to be capable of developing an exposed silver halide emulsion. Photographic utilization of ascorbic acid has been limited, how ever, because of its acknowledged weak action as a silver halide developing agent.
• X and Y each are lower alkyl or hydrogen, provided that at least one of X and Y is lower alkyl, i.e., an alkyl group of from 1 to carbons.
• the lower alkyl group is a methyl group.
• the ascorbic acid ketals are useful as silver halide developing agents in both conventional or tray development and diffusion transfer processes.
• the ascorbic acid ketals may be used as the sole silver halide developing agent, although they are most effective when employed in combination with another silver halide developing agent.
• the developer composition may include the usual components, it being generally found that an ascorbic acid ketal frequently may simply be used to replace ascorbic acid or isoascorbic acid in known developer formulations.
• Diffusion transfer processes are well known and the details thereof need not be given here. It is sufiicient to note that in such processes an exposed silver halide emulsion is treated with an aqueous alkaline processing composition, exposed silver halide is developed and an image wise distribution of diifusible image-forming components is formed as a function of the point-to-point degree of development. This imagewise distribution of diffusible image-forming components is transferred, by diffusion, to an image-receiving stratum positioned in superposed relationship with the silver halide emulsion, thereby forming a transfer image in or on said image-receiving stratum.
• the transfer image is to be a silver image
• processing is effected in the presence of a silver halide solvent, such as sodium thiosulfate, which forms a diifusible complex with undeveloped silver halide.
• a silver halide solvent such as sodium thiosulfate
• silver halide solvent refers to reagents which will form a soluble, dilfusible complex with silver halide, as is well known in the art of forming silver images by transfer.
• the processing composition includes a film-forming, viscosity-increasing material, and a thin layer of the processing composition is spread between the exposed silver halide emulsion and the imagereceiving stratum as they are brought into superposed relationship; see, for example, U.S. Patents Nos. 2,543,181 and 2,647,056 issued to Edwin H. Land.
• the image-receiving stratum preferably includes a silver precipitating agent, as is also well known in the art.
• the processing composition may include a silver precipitating agent, and a solidified layer of said processing composition may be employed as the image-receiving stratum, as described in U.S. Patent No. 2,662,822, also issued to Edwin H. Land.
• Example 1 A mixture of g. L-ascorbic acid, 75 cc. of 2,2-dimethoxy-propane, 50 cc. of dioxane and 0.5 cc. of trifiuoroacetic acid was heated with distillation on a steam bath for 7 hours. The solution was then evaporated under vacuum at 60 0, giving 11 g. (90% yield) of 5,6-isopropylidene-L-ascorbic acid as an oil-white powder. The product was recrystallized from a minimum amount of a 50:50 mixture of acetone and 2 B ethanol to give a white solid, melting at 206-209 C. (dec.) and soluble in water and dioxane.
• Example 2 The efficiency with which an exposed silver halide emulsion was developed by the ascorbic acid ketals was tested as follows: four silver halide negatives were exposed to a step tablet and processed by spreading a layer of processing composition 0.0026" thick between the exposed negative and an image-receiving element.
• a processing composition base was prepared comprising:
• Aqueous solution of lead acetate and cadmium acetate (100 cc. H O; 2.9 g. lead acetate; 2.1 g. cadmium acetate) cc 6.4
• the processing compositions were prepared by adding 0.6 g. of each developing agent recited below to different 10 cc. portions of the above processing composition base. After an imbibition period of 60 seconds, the negatives were separated and the transmission Dmax. and D of the negatives (the negatives were fixed during imbibition and were not subjected to further fixing after imbibition) were measured and found to be:
• Example 3 A silver halide negative was exposed to a step tablet and processed by spreading a layer of processing composition approximately 0.0026" thick between the exposed negative and an image-receiving element of the type used in type 42 Polaroid Land film.
• the processing composition comprised 10 cc. of the base described in Example 2 to which 0.6 g. of ascorbic acid and 0.02 g. of 2,4-diaminoortho-cresol were added. This procedure was repeated, retaining the 0.02 g. of 2,4-diamino-ortho-cresol and replacing the ascorbic acid first with 0.6 g. of isoascorbic acid and then with 0.6 g. of 5,6-isopropylidene ascorbic acid. After an imbibition period of 60 seconds, the transmission densities, slopes and speeds of the negatives were measured as follows:
• Example 4 mux. miu. 4/0.5 3/4-1/4 Speed Slope Isoascorbic acid 1. 72 0. 41 64 0.90 Isoascorbic acid plus 5,6-isopropylidene ascorbic acid 1. 69 0. 42 64 0.80
• Isoascorgie acid 1. 4 0.06 Isoascorbic acid plus 5, G-isopropylidene ascorbic acid. 1. 46 0.08
• the ascorbic acid ketals may be used in combination with ascorbic acid or isoascorbic acid to obtain a more desirable balance of sensitoinetric results, while maintaining maximum and minimum densities without substantial change.
• the superposed elements were separated and the image-receiving element contained a dense positive transfer image of low speed and high minimum density.
• the positive transfer image had a lower minimum density and a film speed about four times faster; in addition, examination of the negative showed greater silver development.
• Replacement of the isoascorbic acid with 0.6 g. of 5,6-isopropylidene ascorbic acid gave much faster development.
• Use of a mixture of 0.3 g. of ascorbic or isoascorbic acid in combination with 0.3 g. of 5,6-isopropylidene ascorbic acid gave transfer images of very good density and low highlight density, and equivalent A.S.A. film speeds or exposure indices of approximately 400.
• Example 6 A processing composition comprising: Diethylamine cc 1.0 Isoascorbic acid g 0.4 5,6-isopropylidene ascorbic acid g ..v 0.4 Sodium carboxymethyl cellulose g 0.4 Potassium thiosulfate g 0.02
• ascorbic acid ketals have been employed in the processing solutions in the examples set forth above, it will be understood that they may be initially located in a layer of the photosensitive element or of the imagereceiving element. It it also contemplated that the ascorbic acid ketals may be employed in color diffusion transfer processes.
• the ascorbic acid ketals are particularly useful in the photographic processes disclosed in the copending application of Meroe M. Morse, Ser. No. 438,044, filed Mar. 8, 1965.
• the ascorbic acid ketals are particularly useful in combination with a high-energy aminophenol silver halide developing agent, wherein one or both positions ortho to the hydroxyl group is substituted by a lower alkyl or a lower alkoxy group.
• the ascorbic acid ketals are also useful in silver transfer processes of the type disclosed in the copending application of Edwin H. Land et al., Ser. No. 437,739, filed Mar. 8, 1965.
• a photographic developer composition comprising water, an alkaline material, a silver halide solvent, and a silver halide developing agent selected from the group consisting of compounds within the formula:
• a method of developing a silver halide emulsion which comprises treating an exposed silver halide emulsion with an aqueous solution comprising an alkaline material and a silver halide developing agent selected from the group consisting of compounds represented by the formula:
• X and Y are a lower alkyl group and the other is selected from the group consisting of hydrogen and lower alkyl groups.
• a photographic process comprising the steps of developing a silver halide emulsion with an aqueous alkaline solution comprising a silver halide developing agent and a silver halide solvent in the presence of an image-receiving material superposed on said silver halide emulsion, said developing agent being selected from the group consisting of compounds represented by the formula:
• a process as defined in claim 9, wherein said developing agent is 5,6-isopropylidene ascorbic acid.
• a photographic process comprising the steps of developing a silver halide emulsion with an aqueous alkaline solution comprising a silver halide developing agent selected from the group consisting of compounds represented by the formula:
• X and Y are a lower alkyl group and the other is selected from the group consisting of hydrogen and lower alkyl groups, transferring image-providing components from unexposed areas of said silver halide emulsion to a superposed image-receiving layer to form a positive transfer image.
• a photographic product comprising a support, a silver halide emulsion in a layer on said support, and a silver halide developing agent in a layer on the same side of said support as said silver halide emulsion, said silver halide developing agent being selected from the group consisting of compounds represented by the formula:
• X and Y are a lower alkyl group and the other is selected from the group consisting of hydrogen and lower alkyl groups.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Chemical & Material Sciences (AREA)
• Inorganic Chemistry (AREA)
• Silver Salt Photography Or Processing Solution Therefor (AREA)
• Photosensitive Polymer And Photoresist Processing (AREA)

Priority Applications (6)

Applications Claiming Priority (1)

Publications (1)

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Family Applications (1)

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Cited By (5)

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• 1965
  • 1965-05-26 US US459112A patent/US3337342A/en not_active Expired - Lifetime
• 1966
  • 1966-04-27 DE DE1547993A patent/DE1547993C3/de not_active Expired
  • 1966-05-09 GB GB20510/66A patent/GB1142135A/en not_active Expired
  • 1966-05-12 NL NL6606519A patent/NL6606519A/xx unknown
  • 1966-05-23 BE BE681408D patent/BE681408A/xx not_active IP Right Cessation

Non-Patent Citations (1)

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