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
  • G03C5/40—Chemically transforming developed images
  • G03C5/44—Bleaching; Bleach-fixing

Definitions

• This invention relates to improvements in photographic processing solutions and particularly to solutions designed for removal of metallic silver from, photographic layers.
• both dye images and silver images may be formed in a photographic layer. It is desirable to removethe metallic silver at the end of the process so that a pure transparent dye image remains in the photographic layer. This is generally accomplished by the use of a silver removing bath containing an oxidizing agent for the silver and at the same time or in a subsequent bath dissolving the silver salt thus formed.
• Silver oxidizing agents ordinarily used are potassium ierrlcyanide or acid dichromate bleaches followed by a silver halide solvent -such as hypo.
• Organic solvents suitable for use according to our invention include monohydroxy alcohols such as benzyl alcohol, isopropyl alcohol, butyl alcohol, s-phenyiethyl alcohol, 'y-phenyl-n-propyl alcohol p-and y-diethylaminopropyl alcohol, s-diethylaminoethyl alcohol, nitroethyl and nitropropyl alcohol, turfuryl alcohol. and tetra-lrvdroi'urfuryl alcohol, and aliphatic ketones sucha's acetone.-
• organic solvents may be used in the bleach bath in quantities ranging from about 1% to about 10% of the volume of the bleach solution.
• benzyl alcohol may be dissolved in the solution to the extent -of about 1%. isopropyl alcohol to the extent of 5 to 10% and acetone to the extent oi about 5 to 10%. Acetone is preferred for use in acid dichromate bleaches and the alcohols such "as benzyl alcohol appear to give the best results in potassium ierricyanide bleaches.
• a further object is to provide a means for 40 the complete removal of metallic silver from emulsion layers containing dyes protected by organic solvents.
• a coupler originally present in the emulsion layer U Hydmbmmic 9 and the dye formed from it are dissolved in globom bromide ules of a solvent such as hydrolyzed cellulose acetime hate or tricresyl phosphate which presumably wets water tllie metallic silver as it is formed and thenen- 3 mm 2 coses portions of it which can'no longer be aiiected byaqueous solutions of silver oxidizing 35 g fi mg aggaigam" g 5 ents.
• hypo or other silver salt solvent such as ammonia, potassium thiocyanate or potassium cyanide.
• Our invention is especially useful with oi color photography-such as those described in the Marines t Godowsky "U. 8. Patent 2,304,940
• Patent 2,322,027 referred to above.
• Those applications describe processes or color photography in which discrete particles of a color coupler and an organic solvent for the ooupler'and for the dye formed therefrom are dispersed in a sensitive silver halide emulsion layer.
• the organic solvent used to dissolve the coupler and dye formed from it to be retained in the rescue methods 2 is eilected by the use of our invention.
• Our invention is also useful in other methods of color photography such as that "described in Mannes, Godowsky 8r Wilder U. 8. Patent 2252,- 718, August 19, 1941, and in bleach-out methods of color photography, such as that described in- Seymour U. S. Patent No. 2,184,022, December 19,
• the method of removing silver from a photographic layer containing silver and dye in particles of water-permeable solvent insoluble in water above 20 C.,whiqh comprises oxidizing the silver contained in said solvent to a silver salt in the presence of an organic solvent selected from the group consisting of monohydroxy alcohols and aliphatic ketones, which are soluble in said water-insoluble solvent and removing the silver salt thus formed with a silver salt solvent.
• the method of removing the silver image from a photographic gelatin layer containing said image associated with dispersed particles of a water-permeable organic compound insoluble in water above 20 0.. which comprises convertin said silver to a silver salt with a solution of a silver oxidizing agent and an organic solvent for said water-insoluble organic compound, said organic solvent being selected from the group consisting of monohydroxy alcohols and aliphatic ketones, and removing the silver salt thus formed with a silver salt solvent.
• the method of removing the silver image from a photographicgelatin layer containing said image associated with dispersed particles of a water-permeable organic compound insoluble in water above 20 C. which comprises converting said silver to a silver salt with a solution of potassium ferricyanide and a monohydroxy alcohol which is a solvent for said water-insoluble organic compound, and removing the silver salt thus formed with a silver salt solvent.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Silver Salt Photography Or Processing Solution Therefor (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=9708001

Family Applications (1)

Country Status (3)

Cited By (4)

Families Citing this family (2)

• 1941
  • 1941-01-17 GB GB646/41A patent/GB547975A/en not_active Expired
  • 1941-11-29 US US421042A patent/US2378265A/en not_active Expired - Lifetime
• 1946
  • 1946-09-30 FR FR951529D patent/FR951529A/fr not_active Expired

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