Patent GB-436587-A (GB)
Title: Improved process for the photographic production of pictures in one or more colours
IPC: G03C7/46
Filed: 1934-04-05
Abstract: Light-sensitive material for the production of photographic pictures in one or more colours by synthesis of one or more azo-dyestuffs comprises one or more layers, such as gelatine, paper or cellulose hydrate, dyed with one or more azo-dyestuff components substantive to the layer.  Sparingly soluble components having acidic or hydroxyl groups are used in the form of salts, and solubility may be promoted by the addition of methyl alcohol. The layer may be dyed with an azo-coupling component, a light-sensitive diazo-compound added, and a coloured image produced by development after exposure.  Gelatine treated with both components may be worked up into a silver halide emulsion and the silver image bleached in a bath tanning the gelatine at the exposed parts.  Dyestuff formation occurs at the unhardened parts on treatment with acidified sodium nitrite solution.  Red pictures are obtained from 2 : 3-oxynaphthoic acid a -naphthalide with urea-bis (p-aminobenzoyl-p-phenylenediamine sulphonic acid) and blue with diazotized dianisidine.  The gelatine may be dyed with the azo-coupling component and the silver image converted into an antidiazotate image as described in Specification 387,197, [Group XX].  A yellow picture is obtained from di-o-sulphobenzylidene-4 : 4<1>-diaminodiphenylurea, obtained by reaction of 4 : 4<1>-diaminodiphenylurea with two molecular proportions of o-sulphobenzaldehyde, and the anti-diazotate of b -naphthylamine. The gelatine may be dyed with the azo-coupling component, the silver halide caused to absorb p-nitrobenzenediazonium chloride, and coupling effected.  The gelatine may be dyed with both compounds, the silver image converted into an insoluble nitrite compound, and diazotization effected by treatment with dilute hydrochloric acid solution.  A red picture is obtained from the urea produced by the action of phosgene on p-aminobenzoyl-p-aminobenzoyl-J-acid and the urea-bis (p-aminobenzoyl-p-phenylenediamine sulphonic acid), obtained by the process described in Specification 1441/11, [Class 2 (iii)]. The undiazotized diazo-component may have a substantive character relative to the layer.  Compounds referred to are aminobenzoyl aminobenzoyl derivatives of amino-naphthol-and naphthylamine-sulphonic and carboxylic acids, of cresotinic acid (obtainable by reaction of cresotinic acid with nitrobenzoyl chloride in presence of sodium carbonate, reduction of the nitro-group, reaction with nitrobenzoyl chloride in presence of sodium carbonate and reduction of the product) and of 3 : 6-diaminocarbazole-2 : 7-disulphonic acid, and also the ureas from the above aminobenzoyl compounds.  Other compounds are the benzoyl-, benzyl-, and benzylidene-derivatives of diaminodiphenylureas, of diaminodiphenylthioureas, of diaminostilbenes and of benzidines; 2 : 3-oxynaphthoic acid arylides may be replaced by the arylides of 2 : 3-oxyanthracene-carboxylic acid, of 2 : 3-oxycarbazole-carboxylic acid, of terephthaloyl-acetic acid, of oxycarboxylic acids of diphenylene oxide and diphenylene sulphide, and of a  - naphthindol - 2 - phenyl - 7 - oxycarboxylic acid, and by pyrazolones from 2-p-aminophenylthiazoles and by 2-oxyfluorene, 2-oxyanthracene and 2 - oxy - chrysene.  Specification 298,979, [Class 98 (ii)], also is referred to.