GB413695A - Printing on metal surfaces - Google Patents

Abstract

413,695. Printing by electrodeposition. DIGBY, E. T., 6, Queen Anne's Gate, London. Jan. 17, 1933, Nos. 1524 and 16529. [Class 41.] Imperishable records comprising printed characters, maps, diagrams, illustrations and portraits are obtained by electro-deposition of platinum or a metal of the platinum group on a suitably prepared sheet of incorrodible metal of the thickness of paper, i.e. not exceeding one sixty-fourth of an inch. The deposit should be applied as thinly as requirements permit and should not depend for its visibility on a bas-relief, relief, plastic, recessed or deepedged effect. In one method a design is applied by photo-transfer, lithography or otherwise to a sheet of gold alloy or nickel, and copper or other metal is deposited on the exposed parts. The initially applied design material is then removed and platinum is deposited over the whole to a depth of 0-00004 inch. The sheet is then treated in acid to dissolve the copper or other metal masking, the platinum above it being removed in a broken condition, leaving the design in platinum on a gold or nickel background. In a modification, the copper or other metal is deposited with a matt surface and is not removed, the final product exhibiting the design in bright platinum on a matt platinum background. In a third method a sheet of gold alloy or nickel is coated over its whole surface with copper before application of the design by photo-transfer or lithography. The unmasked portion of the copper is etched down to the gold or nickel level, after which the design material is removed and platinum deposited ; the copper and its overlying platinum are then removed as in the first method. The original sheets may be sandblasted or otherwise treated to obtain a matt effect throughout, or a smooth masking layer of copper or other metal may be deposited on the matt sheet so as to exhibit the design finally in matt platinum on a bright platinum background.