GB503996A - Improvements in photographic contact printing by reflected light - Google Patents

Abstract

503,996. Photographic diazotype layers. KALLE & CO. AKT.-GES. April 5, 1938, No. 10439. Convention date, April 5, 1937. [Class 98 (ii)] [Also in Group IV] In the reflex copying process, light-sensitive diazotype material is employed, the diazo and azo components being so chosen that on development yellow or greenish yellow dyes are formed which absorb light in the region from 3300 to 4400Š. Such copies are suitable for reproduction on diazotype material. As supports, sheets or foils of cellulose hydrate may be used. Mixtures of two or more diazo compounds or of two or more coupling components may be used. Such additional compounds may yield dyes of darker tones so that the copies are more easily legible. Bleaching dyes, e.g. pinacyanol, with or without sensitizers, e.g. thiosinamine, may be included in the material. Further sheets sensitized with diazo compounds or bleaching dyes may be interposed between the material and the light, source during copying. Filters absorbing ultraviolet light, e.g. of aesculine, aesculetine, #- methyl-umbelliferone carboxylic acid or pyrenedisulphonic acid, may be used or these substances may be included in the sensitive layer. In examples, the diazonium chloride of 1- amino - 2 - oxy - 4 - chlorohenzene - 6 - sulphonic acid, 4 - dimethylaminobenzene - 1 - diazonium chloride, and-4-diethylaminobenzene-diazonium chloride are used as diazo compounds. The diazo chloride of 1-amino-2-oxy-6-chlorobenzene-6-sulphonic acid is prepared by diazotizing 2 : 4-dichlor-1-aniline-6-sulphonic acid and treating the product with soda solution. The Specification as open to inspection under Sect. 91 comprises also the use as azo components of alkyl phenols in which the alkyl group contains a residue known to increase the solubility in water, e.g. an amino group, e.g. a dimethylamino or a phenylamino group, a carboxyl group or a hydroxyl group. In, examples, 1 : 4-dimethyl-2-phenol, 1 : 3 : 4- trimethyl-2-phenol, 1-oxymethyl-2-phenol, #- (2-oxyphenyl)-propionic acid, 2-(w-phenylamino)-methyl-1-oxybenzene, 2-(w-dimethylamino)-methyl-1-oxybenzene, 1-oxymethyl-2-oxy- 4-methylbenzene, 1-(w-phenylamino)-methyl- 2-oxy-4-methylbenzene, #-(4-methyl-2-oxyphenyl)-glutaric acid, 1-4-dimethyl-2-oxy-3-oxymethylbenzene, 1-oxymethyl-2-oxy-3-methoxybenzene and 1-(w-phenylamino)-methyl-2-oxy- 3-methoxybenzene. 2-(w-dimethylamino)- methyl-1-oxybenzene is prepared by treating o-nitrobenzyl chloride with dimethylamine, reducing, diazotizing and boiling out. This subject-matter does not appear in the Specification as accepted.