Improvements in or relating to the photographic production of master copies suitable for use in spirit duplicating processes

摘要

981,509. Photographic production of spirit printing master copies. GEVAERT PHOTOPRODUCTEN N.V. Feb. 27,1961 [Dec. 2, 1959], No. 41019/59. Addition to 981,508. Heading G2C The method of the parent Specification in which a layer comprising a dye, such as a dye sheet used for mechanical preparation of spirit printing sheets, is pressed against a gelatine silver halide emulsion layer bearing an image in silver and hardened gelatin to transfer emulsion from the non-hardened areas to the dye layer, and in some instances to transfer dye to the image areas of the emulsion layer, when both layers may be suitable for spirit printing, is modified by using an emulsion layer exhibiting lesser gelatin hardness in the silver image areas than other areas for the transfer. In an example a chloride emulsion on a paper sheet is reflex exposed to a document, treated in a specified metal-hydroquinone developer and then in an acidified cupric chloride-hydrogen peroxide solution, pressed on to a dye sheet which may be a duplicating carbon paper or a hectographic dye sheet, the sheets separated, and the original sheet used for spirit printing.