GB706688A - Photographically produced intaglio printing surfaces - Google Patents

Abstract

706,688. Photographically produced intaglio printing surfaces. GRAVURE ENTERPRISES, Inc. June 19, 1950, No. 15311/50. Drawings to Specification. Class 98(2) An intaglio printing member has a surface comprising printing elements forming a half-tone pattern in which the elements are separated in the high-lights and are connected together in the deeper tones, being bridged by lands defining relatively small cells for carrying ink, the depth of the printing elements between the lands and within the cells being substantially uniform, and the lands and surface of the member apart from the printing elements being of the same height so as to form a doctor blade supporting surface. The lands may be arranged in evenly spaced lines at right angles to each other and at an angle to the lines of the halftone pattern for minimizing moire. The half-tone pattern may have about 120 lines per inch, and there may be about 300 lands to the inch, the lands being less than .001 inch in width. For multicolour printing, the half-tone patterns in the printing members for the different colours may be at different angles (e.g. 0 degrees, 30 degrees, 45 degrees, and 60 degrees) for reducing moirÚ to a minimum, and the angle between the lands and the half-tone lines in the various printing members is the same (e.g. 28.6 degrees). In preparing a printing element, a light-sensitive film or plate is exposed to a fine gravure screen having about 300 lines to the inch to produce a latent image thereof, the half-tone printing surface is inked-up with proving ink or other suitable opaque material and an ink print made on the film or plate bearing the latent image, the film is exposed to uniform light, the ink image is removed with benzine or other solvent, the film is developed and fixed, a positive is printed therefrom, an etching resist is prepared from the positive on line tissue, and the resist is applied to a coppercoated cylinder or flat plate, and a printing surface produced using a single etching bath. Specification 706,689 is referred to.