GB629656A - Process for positive diazo-type and negative metal reproduction images and light-sensitive material therefor - Google Patents

Abstract

629,656. Photographic diazotype processes. FAIRWEATHER, H. G. C. (General Aniline & Film Corporation). Sept. 12, 1946, No. 27454. [Class 98 (ii)] A light-sensitive diazotype layer comprises a diazo compound capable of decomposing under the action of actinic light to produce a reducing agent, a coupling component which will form with the diazo compound an azo dye having high ultraviolet transmission characteristics, and a reducible non-light-sensitive salt of silver, mercury or thallium, the diazo compound being in such form that it will not react to convert the salt to a light-sensitive form. On exposure of this layer to ultra-violet light under a negative pattern and development with ammonia, an azo dye is produced in the parts protected from light and a metallic deposit in the parts exposed to the light, and the print as made is used as a transition print for production of positives on ordinary diazotype layers by exposure with ultra-violet light and ammonia development; thus a number of positives can be made from a negative without the necessity of wet-developing, washing or fixing operations. A list of diazo compounds which may be used includes 4-amino-N-ethyl- 1 - cyclohexylaminobenzene, 2.5 - diethoxy - 4 - phenylmercaptoacetylamino - 1 - aminobenzene, 4.4<SP>1</SP>-diamino-2.2<SP>1</SP>-5.5<SP>1</SP>-tetraethoxy triphenylmethane, N -benzene 1.2.3.4 - tetrahydroxy - 6 - aminoquinoline, 5 - amino - 2-methyl -N benzyl - 2.3-dihydroindole, 6 - amino - 9 - ethylhexahydro - carbazole, N-p-(aminophenyl)-morpholine, N- p - aminophenyl piperidine, N - ethyl - N - (4 - amino - 3 - methyl phenyl) - glycineamide, and 1-(p-aminophenyl)-pyrrolidene. Coupling components include 2.3-dihydroxynaphthalene, 1- amino - 8 -hydroxy - 3.6 -naphthalene disulphonic acid, 6-hydroxy naphthimidazole, R-salt, 2.3- dihydroxynaphthalene - 6 - sulphonic acid, H- acid, 2.4-dihydroxybenzaldehyde and dimethyldihydroresorcinol. Of the metal salts, silver, mercurous and thallous nitrates and sulphamates are particularly suitable. Paper, cellulose acetate foil or gelatin coated cellulose acetate foil may be used as ultra-violet light transmissive support for the layers. In eight examples the diazo compounds used are the fluoboric acid salts of diazotized p-aminodiethylaniline, p-amino-N.N-diethyl-metatoluidine or p-amino-diphenylamine; the coupling components 2.3 - dihydroxynaphthalene, 1- amino - 8 -hydroxy- 3.6-dihydroxynapbthalene, or 6-hydroxy-naphthimidazole; and the metal salts silver nitrate or sulphamate: these substances being added in various specified proportions, together with citric acid, to form the necessary coating solutions. Specification 391,677 is referred to.