GB341454A - Colour photography - Google Patents

Abstract

341,454. Colour photography. MARTINEZ, M., 10, Adelphi Terrace, Adelphi, London. July 15, 1929, No. 21690. [Class 98 (ii).] In a process of colour photography an exposed surface comprising two or more layers each containing or overcoated with a different single colour dissolved or suspended in the layer, is treated during or after development and fixing to remove the colour either from the light affected parts or from the parts not so affected. The removal may be carried out by treatment with acidified hydrogen peroxide or by hardening the gelatine of the exposed parts and removing the unhardened parts along with the colour therein. Colour particles may consist of silver erythrosinate, ferricyanide, or chromate, coloured salts of mercury or other metals e.g. nickel dimethylglyoxime, sulphides or oxides, coeruleum, cobalt blue, ThÚnard blue metallic resinates and animal or vegetable colouring matters. Dyes used include carmine, erythrosine or iodo-eosine for red, tartrazine or carmathine for yellow, logwood, indigotin or indigo-carmine for blue and quinoline or alizarine colours. Substances not in themselves coloured but which yield a colour on suitable treatment, such as nickel, copper, ferric or uranium salts, dimethylglyoxime, benzoin oxime, alpha- and #- naphthylamine and leuco compounds, may also be used. In an example a support S of celluloid is coated with a fast silver bromide emulsion E3 containing smalt, and on the opposite side a similar emulsion E2 thinned by the addition of 30-50 per cent of gelatine solution containing tartrazine, over which is coated a second layer thinned with 40-60 per cent of a saturated solution of erythrosine with 7 per cent of gelatine. After exposure the affected parts shown cross hatched in Fig. 1 are removed with acidified hydrogen peroxide, the resulting layer being shown in Fig. 2. Specification 222,523, [Class 98 (ii), Photographic processes &c.], is referred to.