GB369414A - Improvements in or relating to reproducing the surface markings of wood and other material - Google Patents

Abstract

369,414. Photo-mechanical printing- plates. TENNANT, W..J., 111, Hatton Garden, London.-(Oxford Varnish Corporation ; Empire Building, Detroit, Michigan, U.S.A.) March 31, 1931, No. 9777. Drawings to Specification. [Class 98 (ii).] In a process for imitating the graining of wood or other natural material on a hard surface such as metal, of the kind in which the design is applied over a ground colour by means of photographically-produced and etched printing-plates as described in Specification 169,515, [Class 98 (ii), Photographic processes &c.], one of the printing-plates carries a reproduction of part only of the grain pattern, while another carries a reproduction of the whole of the pattern. The part reproduction shows the part of the original not containing the darker grain pattern and in which occur " undertonings " in a colour between those of the ground and of the darker grain. The plate may be prepared by tracing on to a transparent sheet such as celluloid the general pattern of the darker grain areas of the original particularly where the " undertonings " appear to show outside the darker grain lines, a rough equivalent of a photographic positive being thus produced. This is printed on to a carbon resist and the design on the resist is broken up by subsequent exposure through a Rembrandt screen. The resist is then employed to etch a plate or roll slightly. Alternatively, the original can be photographed, preferably with a brief exposure and if desired blocking out the parts where the " undertoning " is not apparent, a positive produced from the photograph and a carbon resist produced therefrom. The colour applied by the " undertoning plate is such as will blend with the ground colour to produce a correct result, the ground colour being lighter than that normally employed. If more than one colour occurs in the " undertoning " the predominant one is applied by printing and the others are worked in by hand, or a printing-plate may be prepared for each colour. The reproductions on the " undertoning" and full grain plates are preferably arranged to print out of register, for example by taking one of the photographs out of focus. The " undertonings " are preferably applied direct to the ground colour, but if desired the full grain reproduction may be applied first.