GB293347A - Process of treating and producing light-sensitive layers on photographic and heliographic papers - Google Patents

Abstract

293,347. Schwickert Ges., R., and Burg, E. July 4, 1927, [Convention date]. Void [Published under Sect. 91 of the Acts]. Azo compounds; nitroso compounds.-The process of Specification 284,253, [Class 98 (ii), Photographic processes &c.], is modified by using as the light-sensitive media compounds produced by the action on diazo or nitroso bodies, such as diazotized 1-amino-2-naphthol-4-sulphonic acid, nitrosophenacetin, nitrosophenlactin, or aminophenol substituted by succinic acid, of alkali cr alkaline earth salts of aliphatic acids and oxyacids, aromatic carboxylic acids or sulpho acids, amido acids, &c., such as acetic, succinic, lactic, citric, tartaric, oxalic, benzoic, benzenesulphonic, cinnamic, and phenylacetic acids. The compounds are formed as precipitates by dissolving excess of the salt in a warm saturated aqueous solution of the diazo body or nitrosamine, and allowing to stand. Or concentrated solutions of the salt and of the diazo body or nitrosamine may be mixed together. Or, when a diazo compound is to be formed, it may be produced directly by diazotizing in a. solution of one of the aforementioned acids instead of in mineral acid, and neutralizing excess acid with alkali. To the lightsensitive layer may be added (1) hygroscopic substances such as alkali acetate or magnesium chloride, (2) acid salts such as alkali bisulphates, (3) substances such as organic acids to prevent coupling when coupling bodies are included in the layer, (4) oxidizing agents such as bichromates or alkali persulphates, perborates, and percarbonates, in order to deepen the colour of the pictures, and (5) catalysers to increase the effect of the oxidizing agents.