GB507485A - Photographic light-sensitive material for colour photography - Google Patents

Abstract

507,485. Colour photography. GASPAR, B. Dec. 9. 1937, No. 34079. [Class 98 (ii)] A multilayer light-sensitive material comprises support carrying a plurality of superimposed silver halide emulsion layers each differently sensitized and at least one of the layers containing a dye which is fast to ordinary photographic treatment solutions but can bo locally bleached in the presence of a silver image and absorbs the light rays for which the layer is predominantly sensitized, another layer being arranged behind this coloured layer and sensitive to these light rays so that a removable filter dye of substantially the same colour as the other dye is present in a layer in front of the second layer but not in front of the first layer. The concentration of the imageforming dyestuff is sufficient, for the colour intensity at the most intensely coloured parts of the image. The filter dye may he one that is destroyed by the photographic developers and is included in the first layer or in a separate layer of clear colloid between the two layers. In the example described, a paper support carries a blue-green emulsion sensitized to red light, a magenta dyed emulsion sensitized to green and a yellow dyed emulsion sensitive to blue. The top layer contains Xylenewalkgelb G in the form of its calcium salt, and in the same layer or in a separate gelatine layer as the yellow, dyestuff 4 : 4<1>-methenyl-bis-[1-(psulpho-phenyl)-3-methyl-pyrazolone-5]. The magenta layer contains Tuchechtbrillantrot 2B as its n-methyl-naphthoquinolinium salt and in the same or a separate layer either the sulphonic acid derived from methenyl-bis-oxythionaphthene or the red dyestuff obtained from 1-(psulpho - phenyl) - 3 - methyl - pyrazolone - 5 and #-anilino-acroleine-anile, The next layer is panchromatic and contains Pontamine Sky Blue 5BX. The material is exposed behind coloured or black and white positive part images and the image-forming dyestuffs locally destroyed by an acid thiocarbamide solution or 5 per cent hydrobromic acid, the other dyestuffs having been destroyed in the development. Specification 506,385 is referred to.