GB567126A - A process for the production of a printing roller to reproduce half-tone copies by photo-mechanical means for textile printing - Google Patents

Abstract

567,126. Photo-mechanical printing surfaces. HEBERLEIN & CO., AKT.-GES. Sept. 29, 1941, No. 12578. Convention date, Nov. 20, 1940. [Class 98 (ii)] An intaglio printing roller having dot-form lands for supporting the doctor is made by photographing the original in a camera having in front of the sensitive film a transparent-dot screen so that the copy is resolved into areas of unequal size, but equal tonal depth, developing the film and, if desired, retouching the negative, printing therefrom a diapositive and chemically reducing this, locally if desired, so that the white dots in the shadows may become more apparent and so yield broader and more wear-resisting land dots on the roller, printing the diapositive on to a roller having a sensitive layer of the wash-out relief kind, developing the layer with water, and finally etching the roller through the layer in known manner. Instead of using the transparent-dot screen in the camera, it may be interposed in printing the diapositive from the camera negative, a punctiform printing light-being used. Instead of chemically reducing the diapositive, the negative may be intensified; and instead of printing the diapositive directly upon the sensitized roller, a master diapositive prepared from it by the known step and repeat printing method may be so used-this master may be equal in length to the length of the roller, and its breadth may,be a submultiple of the circumference of the roller, around which it may be stepped in successive printings. Separate diapositives may be prepared with the aid of colour filters and used to make rollers for multi-colour printing.