Etching

In this proce the copper plate is covered with an etching-ground, which is a preparation of bees’-wax, Burgundy pitch, black pitch, and asphaltum (or other ingredients); and the lines of the design are traced out with etching-needles, which remove the etching-ground from the copper wherever they pa , and slightly scratch the surface of the plate. Next, a border of banking-wax is put round the sides of the plate, making a trough of it. The banking-wax is made of bees’-wax, common pitch, Burgundy pitch, and sweet oil melted in a crucible and poured into cold water. The next operation is to pour in nitrous acid reduced with water to a proper strength (about one part acid to four parts water). When the acid has been on a sufficient time to corrode the fainter parts of the subject, it is to be poured off, the plate washed with water, and left to dry. These fainter parts are then to be varnished with a mixture called stopping-ground, made of lamp-black and Venice turpentine, applied with a camel’s-hair pencil. This stops the further action of the acid on these parts. When the surface is dry, fresh acid is poured on to bite in the bolder parts, and the proce es of stopping and biting-in are alternated for every gradation of tint. The wax is removed from the plate by heat, and cleaned away with a rag moistened with olive oil; and the work is then complete, or it may be finished off with the graver. Etching-points or needles resemble common needles, fixed in handles four or five inches long; some are made oval to produce broader lines. The dry point is only a very fine-pointed needle for the delicate lines. Imitations of chalk and pencil drawings are sometimes