GB954205A - Improvements relating to the production of photographic gelatin relief images - Google Patents

Abstract

954,205. Photographic processes. GEVAERT PHOTO-PRODUCTEN N. V. June 30, 1960 [July 1,1959], No. 22981/60. Heading G2C. A photographic relief image is obtained by developing an exposed gelatins silver halide emulsion layer with a developer comprising a tanning developing agent, a quaternary ammonium or tertiary sulphonium compound as development accelerator and a softener for gelatin, and then removing the unhardened gelatin. The unhardened gelatin may be removed by washing, scouring with a rubber scraper, or by pressing against a receiving sheet such as of paper to which the gelatin is transferred. The tanning developer may be catechol or pyrogallol and the softener may be urea, formamide, ethylene chlorohydrin or sodium solicylate. In the examples, the development accelerator is ethylene dipyridinium dichloride,p-nitrobenzyl pyridinium chloride or dimethyl lauryl sulphonium methosulphate, and the developing solutions also contain sodium carbonate, potassium bromide and potassium ascorbic-borate or potassium sulphite. Other development accelerators specified are pyridinium salts wherein the N atom has a #-hydroxyethyl, methylcarbchydrazide, p-chlorobenzyl or benzimidazolyl-2-methyl substitutent or wherein two pyridinium groups are linked by their N atoms to trimethylene or pentamethylene chains, tetraethyl ammonium ethosulphate, trimethyl-lauryl ammonium chloride, N-methyl-N-p -nitrobenzyl piperidinium chloride, N-hexyl -N-p -nitrobenzyl morpholinium chloride, 1, 2, 3, -trimethyl-naphthimidazolium methosulphate, 1, 4-dimethyl-quinolinium methosulphate, trimethylene-di-iso-quinolinium dichloride and trimethylene-di-N, N<SP>1</SP>-p-nitrobenzyldipyrolidinium dichloride. One or more of the ingredients required may be incorporated into the photographic material. Thus the silver halide emulsion layer may contain urea and/or a tanning developer. This invention may be applied to the silver salt diffusion process wherein an exposed silver halide emulsion is developed according to the invention and pressed against a receiving sheet and the unhardened areas of the receiving sheet removed as above. Specifications 614,155, 804,076, 821,251, and 862,615 are referred to.