GB480291A - Colour photography and kinematography - Google Patents

Abstract

480,291. Colour photography. TRUECOLOUR FILM, Ltd., DOLGORUKI, E. SANDERS-, and REINDORP, J. H. April 14, 1937, No. 10602. Addition to 480,287. [Class 98 (ii)] Differently coloured images are produced in exposed superimposed silver halide emulsion layers or strata by developing both images to silver, bleaching both images to colour-developable silver salt images, converting the upper image into silver iodide, colour-developing the lower image, and colouring the upper image in any suitable manner, for instance by dyetoning, or by applying a coloured colloid layer and treating the material in a bleach-hardening bath or by converting the silver iodide to another colour-developable silver salt and colour-developing. The silver images may be bleached to silver ferrocyanide by an ammoniacal potassium ferricyanide bath and the upper image converted to silver iodide by an iodine - potassium iodide bath containing glycerine, followed by a sodium sulphite stop bath. The silver developed in the lower layer is removed prior to colouring the upper layer by bleaching to silver ferrocyanide and dissolving out the latter by sodium sulphite solution. Material with two layers on one side and one on the other is processed by developing, bleaching all the images to silver ferrocyanide images, and differentially processing the twolayer side by flotation, or by applying varnish to the single layer side, or by applying the iodine solution by a roller. Alternatively, the image on the single-layer side may be also converted into silver iodide, the lower image on the two-layer side colour-developed and the silver iodide images re-converted into silver ferrocyanide and differentially colour-developed.