GB441411A - Improvements in processes of sensitizing photographic silver-halide layers incorporating colouring matter - Google Patents

Abstract

441,411. Colour photography. GASPAR, B., 5, Avenue Helene, Antwerp, Belgium. Aug. 10, 1934, No. 23160. Convention date, Aug. 10, 1933. Drawings to Specification. [Class 98 (ii)] To silver halide emulsion layers, having incorporated in them dyestuffs which are selectively destroyed at the image or non- image parts to form coloured images, sensitizers are added for the purpose of modifying the gradation of the images. If the sensitization maximum of the sensitizer is near the absorption maximum of the dye used to colour the layer a flat gradation is obtained, and if the maxima are farther apart a steeper gradation. The method may be used to render the gradations of superposed layers or of the particles of an emulsion consisting of differently coloured mixed particles the same. Examples are given of (1) an emulsion coloured with chrysophenine and sensitized with either pinaflavol or erythrosine ; (2) three superposed emulsion layers coloured with Diamine Pure Blue FF, Diamine Fast Pink BBF, and Chrysophenine respectively, the blue layer being sensitized with thioisocyanine ethyliodide, the yellow with erythrosine, and the red with kryptocyanine. The gradation of the red may be made flatter by employing thiazoline tricarbocyanine or another sensitizer for the deep red ; (3) a support having a layer on one side coloured with chloramine light Red 7BL and Chrysophenine and sensitized with pinacyanol, selenocarbocyanine, 6: 61-dimethyl-5: 51 - dibromindocarbocyanine ethyliodide, 6: 6<1>-dimethylindocarbocyanine ethyliodide, or indocarbocyanine ethyliodide according to the gradation of the layer on the opposite side of the support which is coloured with Diamine Pure Blue FF and Chrysophenine and, when pinacyanol is used to sensitize the red layer, is sensitized with thiocarbocyanine ethyliodide. The gradation of the layers may also be chosen in accordance with the gradation of the master image from which the layer is to be printed or with the rate of bleaching of the dyestuffs included in the layers. Specifications 379,679, 395,718, 397,159, 397,170, 397,188, 408,991, and 415,040 are referred to.