ELECTROTYPING (Fr., Electrotypage, Galvano plastie ; Ger., Galvanoplastik) A process by which engraved plates, type formes, etc., are reproduced. They are pressed into a layer of beeswax, the resulting mould is blackleaded by brushing or by spraying with a solution of blacklead, to make the surface cou ductive, and the mould is then suspended in a solution of copper sulphate, a copper plate being suspended opposite and near to the mould to form an anode. The two are connected to a source of electric current, and copper is then deposited in a thin shell on the mould until thick enough to be stripped off. ThiS shell is filled up at the back with type metal to give it sufficient thickness and solidity, and after being planed at the back and mounted on a wood or metal block is ready for printing from.
Photographic reliefs in gelatine have also been electrotyped. (See " Swelled Gelatine Process.")
The late G. Scamoni, of St. Petersburg, suc ceeded in electrotyping from the image of a wet collodion negative. Nickel, nickel steel, iron, brass, and other metals have also been success fully deposited by electrotyping. In the Ord nance Survey Office, Southampton, original engraved maps are reproduced by electrotyping. The copper plate is silvered to prevent the copper from adhering, and a thick shell is deposited. This is in relief, and forms the matrix from which any number of duplicates may be made. The matrix is silvered and deposited on in the same way as upon the original. Major-General Waterhouse, when at the Survey of India, successfully electrotyped from a photographic carbon image developed on the copper plate. (See also " Daguerreotypes, Electrotyping.")