Patent GB-562019-A (GB)
Title: Improvements in sensitive colour photographic materials
IPC: G03C7/28
Filed: 1942-12-09
Abstract: 562,019. Colour photography. KODAK, Ltd. (Eastman Kodak Co., and Seymour, M. W.). Dec. 9, 1942, No. 17515.. [Class 98 (ii)] Highlight stain is prevented or minimised in colour photographic material comprising at least two differently colour sensitive silver salt emulsions in superposed layers not separated by a water-impermeable layer, at least one of which is diffusely dyed with a dye bleachable only through the chemical or catalytic aid of a silver image or a silver compound image and having therebetween a water-permeable colloid layer containing unexposed silver salt having an effective sensitivity to light of the colour to be recorded by an adjacent dyed emulsion layer by forming colour component latent images in the colour sensitized emulsions and in the waterpermeable colloid layer, developing silver images in all of the layers containing silver salt, and treating the material in a bath which will bleach the dye in the diffusely dyed layer and the dye which has diffused therefrom into the water-permeable colloid layer in the region only of the silver or silver compound images. In a modification, the layers may contain, dyeformers or dye derivatives, which may be converted into bleachable dyes after exposure and development, The material may comprise a support, a silver halide emulsion layer effectively sensitive to red light and containing a bleachable dye, an uncoloured unexposed silver halide emulsion interlayer effectively sensitive to 'red light or to green light or to both, a silver halide emulsion layer effectively sensitive to green light and diffusely dyed with a bleachable dye, an uncoloured unexposed silver halide emulsion layer having an effective 'sensitivity to green light or to blue light or to both, and a not specially colour sensitized silver halide emulsion containing a bleachable dye. The material may alternatively have only two image-recording layers and a single interlayer. The interlayer may contain a decolourisable filter dye. The material may comprise a red-sensitized silver halide emulsion layer containing a blue-green dye, an uncoloured interlayer, a green-sensitized silver halide emulsion layer containing a magenta dye, a second uncoloured interlayer, and a not specially colour-sensitized silver halide emulsion layer containing a yellow dye. If the blue-green dye tends to diffuse, the first interlayer contains a small quantity of redsensitized silver halide emulsion. If both the blue-green and magenta dyes tend to diffuse, the first interlayer contains a small quantity of silver halide emulsion both red and green sensitized. If the yellow dye tends to diffuse, the second interlayer contains a small quantity of not specially colour-sensitized silver halide emulsion. If both the yellow and magenta dyes tend to diffuse, the second interlayer contains a small quantity of silver halide emulsion sensitive both to green and blue light. The interlayer may also contain the decolourisable yellow filter dye. One of the emulsions may be infra-red sensitive, and the interlayer may contain a small quantity of infra-red sensitized silver salt emulsion. Specifications 507,211 and 546,704 are referred to.