GB483059A - Improvements in the manufacture of colour prints and matrices therefor - Google Patents

Abstract

483,059. Photo - mechanical printing of colour films. ARMSTRONG, J. J. V. Oct. 7, 1936, Nos. 27184/37 (divided out of 483,044), 28247/36, and 31613/36. Drawings to Specification. [Class 98 (ii)] Mosaic screen additive colour pictures or kinematograph films are analyzed into records of the single component colours and each record used to prepare an etched printing plate or strip which is inked and the records printed in superimposition on a common receptive surface. The plates are prepared by printing by means of coloured light, colour filters, or stop-out screens onto light-sensitive layers on strips of etchable material without the use at any stage of a gravure or other photomechanical screen. The printing strips may be of celluloid or metal, e.g. copper. As sensitive material, a silver bromide emulsion or a carbon tissue sensitized with potassium or ammonium bichromate on a separate support may be used, the layer after exposure being transferred to the metallic strip. When a stop-out screen is used this may be separate from the metallic strip or may be applied thereto as a resist before or after the application of the sensitive layer. Preferably, the original mosaic screen consists of juxtaposed hexagonal areas of red, green, and blue, in which case the stop-out screen may cover slightly more than two-thirds of the area so as to allow latitude in registration. The receptive surface may be of paper or of cellulose acetate; when the latter is used, the printing ink preferably contains a solvent for cellulose acetate, e.g. acetone. Registration may be effected by printing a series of interrupted lines on the margin of the strip and scanning these with a photo-electric cell connected to means for displacing or stretching the strip if the lines come out of register with the cell.