Patent GB-490451-A (GB)
Title: Improvements in the production of coloured photographic pictures
IPC: G03C7/28
Filed: 1936-12-14
Abstract: 490,451. Colour photography. GASPAR, B. Dec. 14, 1936, Nos. 34258/36, 9568/37, and 23386/37. [Class 98 (ii)] A bath for the production of dyestuff images from silver images in photographic materials diffusely dyed with reducible dyestuffs, includes a substance itself incapable of reducing the dyestuff but capable of reacting with the silver of the image to reduce the dyestuff selectively at those parts and is characterized by the presence therein of small amounts of colourless or coloured organic compounds such as phenazine, quinoxaline, or diphenylmethane derivatives or sensitizing dyes, which compounds are readily reducible under working conditions and the reduction products of which are readily oxidizable under the same conditions, the additions acting as accelerators for the dyestuff destroying agent during the conversion of the silver image into a reversed dyestuff image. Accelerators referred to are 2 : 3-diaminophenazine, 2 - hydroxy - 3 - aminophenazine, quinoxaline, 2 : 3-dimethylquinoxaline, 2: 3- diphenylquinoxaline, 2 - hydroxy - 3 - methylquinoxaline and compounds of the general formulµ where X and Y represent nitrogen, sulphur, oxygen, carbonyl or carbimino. The compounds may be substituted by amino-groups, hydroxy-groups, sulphonic groups, or other groups. Dyestuff-destroying agents referred to are hydrohalic acids including hydrochloric acid, and hydrobromic acid, thiocarbamide with hydroquinone, chrome alum and sulphuric acid, potassium bromide and sulphuric acid, sodium hyposulphite, sodium chloride and hydrochloric acid, magnesium chloride and hydrochloric acid and compounds capable of forming complex silver compounds. Other accelerators referred to are benzhydrol, alpha-benzildioxime, benzophenone anil, cyanamide, diacetylmonomethoxime, diacetylmonoxime, dibenzylamine, diphenylpiperazine, diphenylthiocarbazone, hydrobenzamide, methyleneaminoacetonitrile, quinizarine, quinophthalone, 2: 2<1>: 4: 4<1>- tetramino - 5: 5<1> - dimethyldiphenylmethane, tetraethyl - p - diaminobenzophenone, tetraethyl - pp<1> diaminodiphenylmethane, benzothiodiazol, NN<1> - di(p - aminophenyl) - NN<1>- dimethylethylenediamine, methyl violet B, auramine, diacetyl - p - phenylenediamine, sdiphenylethylenediamine, 2: 4 - diaminodiphenylamine, quinizarinesulphonic acid, sodium indigosulphonate, 1:2: 4-triaminobenzenetrihydrochloride, tetramethyldiaminobenzhydrol, tetramethyl - p - diaminobenzophenone, tetramethyl - p - - phenylenediamine hydrochloride, tetramethyl - p - diaminodiphenylmethane, N- methylquinolone, acetonephenylhydrazone, acetoneoxime, acridone, 6-aminopurine sulphate, aminopyrine, allantoin, anthraquinone- #-sulphonic acid, benzalmethylamine, diacetylo-phenylenediamine, benzthiazylhydrazine, 2- chloro - 4 : 6 - diaminobenzene, s-diphenylcarbazide, anthraquinone, 1-aminoanthraquinone, 2-aminoanthraquinone, anthragallol, 1-methyl- 2 - pyridone, alizarine red S, alizarine red, dihydro - 2 - hydroxyquinoxaline, fuchsine, anthraquinone - # sulphonic acid, dimethylaminostyryldimethylthiazole - N - methyliodide, 6 - methoxypseudocyanine - N - ethyliodide, N - ethyl - 6 - methoxythiocarbocyanine iodide, N - ethylbenzthiazolecarbocyanine iodide, quinone, benzalaniline, hexamethylenetetramine, benzalazine, p - toluenesulphinic acid, benzene-1-sulphonic-3-sulphinic acid, naphthalene - 1 - sulphonic - 4 - sulphinic acid, 3-nitrostyrylquinolinium - N - ethyl - ethylsulphonate, 3 - nitrostyryl - benzthiazole ethylsulphonate, 3-sulphostyrylpseudo-thiohydantoin, 2-styryl- N -ethylquinolinium-ethylsulphate, 4-dimethylaminostyrylrhodamine, and bis-(4-dimethylamino-2-nitrophenyl)-disulphide. The quantities used may be from 0À05 to 0À8 per cent and quantities of 0À001 per cent are in some cases sufficient. Specifications 395,718, 397,159, 397,188, 397,192, and 477,524 are referred to.