Photographic processes

1,011,000. Photographic reversal processes; colour developers. ILFORD Ltd. Feb. 12, 1964 [Feb. 26,1963], No. 7764/63. Heading G2C. In a photographic reversal process, the residual silver halide is rendered developable by treatment with an aqueous solution of a stable amine-borane of the formula:- wherein R 1 and R 2 are hydrogens or alkyl, aryl or aralkyl groups R 3 in formula I is an alkyl, aryl, aralkyl or saturated carbocyclic group and in formula II is methylene or polymethylene, or R 1 amd R 2 may together with the nitrogen complete a heterocyclic ring provided that R 3 in formula I is hydrogen. The invention may be used in the reversal development of a colour image in a multilayer material wherein after the black-andwhite development each layer is selectively reexposed and developed in a colour developer containing the appropriate colour coupler. According to the invention, the last re-exposure (e.g. of the green-sensitive middle layer) is omitted and the material is treated with the amine-borane solution. Where the colour couplers are included in the light-sensitive material, the material is treated according to the invention after the black-andwhite development. In either case, the amineborane may be applied as a separate bath before colour development, which bath may include sodium or barium hydroxide, or it may be included in the colour developing solution itself. Amino-boranes specified are the boranes of dimethylamine, trimethylamine, cyclohexylamine, benzylamine, hexamethylene diamine, piperidine and morpholine.