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
  • G03C1/06—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein with non-macromolecular additives
  • G03C1/34—Fog-inhibitors; Stabilisers; Agents inhibiting latent image regression
  • G03C1/346—Organic derivatives of bivalent sulfur, selenium or tellurium

Definitions

• This invention relates to novel antifogging and stabilizing agents for use with photographic silver halide emulsions, to photographic films coated with light sensitive silver halide emulsions associated with our novel antifogging and stabilizing agents and to processes for producing such films.
• an object of this invention to produce a light-sensitive emulsion'which is fast, stable, has a reduced tendency to fog and has good contrast.
• a further object of this invention resides in a lightsensitive emulsion which contains a compound which stabilizes the emulsion against fogging and at the same time does not materially reduce the speed and/or contrast of the emulsion.
• Still further object of this invention is to provide a light-sensitive emulsion containing a compound which stabilizes the emulsion against fogging and at the same time does not appreciably reduce the sensitivity to light of longer wave length eifected by the presence of sensitizing dyes.
• Dithiocatechol or derivatives Dithioresorcinol SIH Dithiohydroquinone wherein R is H or alkyl The preparations of dithiocatechol are described in Beilstein, vol. VI, page 397. The preparations; of dithioresorcinol are described in Beilstein, vol. VI, page 834. The preparations of dithiohydroquinone are described in Beilstein, vol. VI, page 867.
• the antifogging agents of our invention may be added to the emulsion at any stage during its process of production. Thus, they may be added as a ripening final or as a coating final. When added as a ripening final, they are added during the ripening or sensitivity increasing stage of the emulsion making process. Such addition may be made before, during or after the addition of the soluble silver salt tothe soluble halide in the presence of a suitable colloid, such as gelatin, polyvinyl alcohol, solubilized casein or albumin.
• a suitable colloid such as gelatin, polyvinyl alcohol, solubilized casein or albumin.
• the antifogging agent of our invention is added to the emulsion just prior to coating it on a suitable support such as glass, paper or film at a time when the emulsion has nearly attained its maximum sensitivity.
• the antifogging and stabilizing compounds of our invention in a separate layer such as an undercoating layer or in an antiabrasion gelatin surface. Sometimes it is desirable to incorporate the compounds in one or all processing baths or in the preand post-baths.
• the .antifoggants of our invention are preferably added to the emulsion in an amount ranging from .1 milligram to 10 milligrams per 0.6 mol of silver halide and when used as a coating final they are preferably added in an amount ranging from 10 milligrams to 50 milligrams per 0.6 mol of silver halide.
• the optimum amount to be added depends primarily on the type of emulsion and should be determined individually in each case.
• the stabilizers andantifoggants of our invention may also be used in combination with known antifoggants and stabilizers.
• the antifoggants of our invention can also be used in combination with sensitizers such as sulfur, metal and reduction sensitizers as well as with accelerators such as the polyoxyethylenes (see U.'S.P. 1,970,578) and their derivatives and polyvinyl-pyrrolidone.
• novel antifoggants of our invention may be used with various types of photographic emulsions, such as non-sensitized, orthochromatic, panchromatic and X-ray emulsions, paper emulsions and color emulsions.
• aqueous filtrate was also extracted with ether and the combined ether extracts dried with Drierite. Evaporation of the ether and distillation of the residue gave 16 g. of dithioresorcinal, B.P. 9293 C./ 3 mm.
• Example II A silver halide emulsion in gelatin containing 2% silver iodide and 98% silver bromide was prepared in a conventional manner and brought up to its maximum light sensitivity. It was then readied for coating, finals were added such as sensitizing dyes and hardening agents. A 0.1% solution of dithioresorcinol was added to the emulsion as an 'anti-foggant and stabilizer. The emulsion samples contained about 0.6 mole of silver halide. The so-prepared emulsion samples were coated on a suitable cellulose ester base and dried. Samples of these film coatings were then exposed in a Type IB sensitometer and developed in a developer of the following composition:
• Example IV is similar to Example II with the exception that toluene-3,4-dithio-l was used in place of dithiore'sorci-
• a silver halide emulsion in gelatin containing 2% silver iodide and 98% silver bromide was coated on film base in a manner known to the After the coating was performed, an aqueous gelatin solution containing 20 grams of gelatin per liter and 20 mg. of dithioresorci- 1101 was coated thereon as an 'antiabrasion layer. After drying, film samples were exposed and processed as described in Example II.
• the samples exhibited a relative speed of 100 and a fog of .20 compared with type coating of the above emulsion having an antiabrasion layer similar to that described above, but lacking the antifoggant and having a speed of 100 and a fog of .30.
• a light-sensitive material comprising a base and a light-sensitive silver halide emulsion thereon, said material containing an antifoggant and stabilizing compound selected from the group consisting of dithiocatechol, the lower alkyl derivatives thereof, dithioresorcinol and dithiohydroquinone.
• a light-sensitive material as recited in claim 1 wherein the antifoggant and stabilizing compound is toluene- 3,4-dithiol.
• a light-sensitive silver halide emulsion as recited in claim 4 wherein the antifoggant and stabilizing compound has the following chemical formula:
• R is selected from the group consisting of H and lower alkyl.
• step 10 which comprises developing said emulsion with a methyl-p--aminophenol hydrochloride-hydroquinone developing solution in the presence of an antifoggant and stabilizing compound selected from the group consisting of dithiocatechol, the lower alkyl derivatives thereof, dithioresorcinol, and dithiohydroquinone.
• an antifoggant and stabilizing compound selected from the group consisting of dithiocatechol, the lower alkyl derivatives thereof, dithioresorcinol, and dithiohydroquinone.
• a process as recited in claim 10 wherein the antifo-ggant and stabilizing compound is dithioresorcinol.
• a process as recited in claim 10 wherein the antifoggant and stabilizing compound is toluene-3,4-dithiol.

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• Physics & Mathematics (AREA)
• Chemical & Material Sciences (AREA)
• Spectroscopy & Molecular Physics (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• General Physics & Mathematics (AREA)
• Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

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Publications (1)

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Cited By (5)

• 0
  • BE BE602317D patent/BE602317A/xx unknown
• 1960
  • 1960-04-11 US US21122A patent/US3008829A/en not_active Expired - Lifetime
• 1961
  • 1961-03-15 GB GB9501/61A patent/GB907267A/en not_active Expired

Non-Patent Citations (1)

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