Photogravure cylinder prodn. from screened positives etc. - uses two image copies to reduce lack of definition

摘要

Production of conventional photogravure cylinders from screened, or offset screened positives involves the copying by means of point source light of the positive intaglio printing screen on the sensitized pigment paper after suitable rotation of the screened positive. In the case of the first image copy, the screen positive with intermediary layer of matt, or scattered film is copied directly on the precopied pigment paper. For the second image copy the screen positive is copied directly onto the precopied pigment paper in order to reduce the lack of definition. The image copy of the screen positive is undertaken using a super-actinic tubular lamp in the region of 300-450 nanometer.