GB1251558A - - Google Patents

Abstract

1,251,558. Photographic silver salt processing compositions. EASTMAN KODAK CO. Feb.27, 1969 [Feb.27, 1968], No.10489/69. Heading G2C. Sludge formation in a silver salt photographic material processing solution is inhibited by incorporating in the solution a compound of the general formula: wherein R is a hydrogen atom or an alkyl group having up to 5 carbon atoms, R<SP>1</SP> is an alkyl group as defined for R, each of R<SP>2</SP> and R<SP>3</SP> is a hydrogen or halogen atom or a hydroxyl, alkyl or amino group and m is zero or an integer of from 1 to 5. The processing solution may be a monobath containing a silver halide solvent (e. g. a thiosulphate) and a silver halide developing agent and from 5 to 20 g. of the compound defined above may be incorporated per litre of this solution where the monobaths are highly alkaline and are used for high temperature processing. The processing solution may be a silver halide developer solution and for normal usage 0À05 to 0À5 g. of the compound per litre is sufficient. Examples given of the compounds defined above are thiolactic acid (2-mercaptopropionic acid), α-mercaptoisolutyric acid, 2-mercaptobutyric acid, 2-mercapto-2- methylbutyric acid, 2-mercapto-3-methylpentanoic acid and 2, 2-dimethyl-3-mercaptopropionic acid. The compounds may be used in developer solutions, development activator solutions, fixing solutions, stabilizing solutions, gelatine hardener solutions and solutions designed for rapid access processing (e.g. thiocyanate solutions). The processing composition of this invention may be prepared in concentrated form in one or more parts, the part or parts being mixed with the appropriate volume of water to give a working strength processing solution. The silver salts in the materials processed may be any of the photo-sensitive silver salts, the halides being the only silver salts exemplified.