The matrix thus dried out to a thick, flexible cardboard is then ready for the casting of the stereotype, which is done by pouring molten stereotype metal against the face of the matrix placed in a casting-box designed for this purpose. A successive number of stereotypes can be cast for the same mat before it is injured by the hot metal. For job-work stereotyping the casting-box is flat, and the molten metal is either poured by hand or automatically pumped in the casting-box.
After the stereotype is cast it is flattened, rough shaved, smooth shaved, bevelled or blocked on wood; the wood base trimmed and then planed type-high for printing press use.
The large daily papers cast the full-page stereotype from which the paper is printed in an automatic casting machine which forms a curved plate, trimmed and bevelled, to fit the cylinder of the press.
Stereotyping was for many years the chief means of making plates for books and also for commercial printing. It has several advantages. The first, obviously, is the advantage which it shares with several other methods of providing a solid printing plate made by molding from an original form of type or engraving. Its peculiar advantage, however, is that it is the quickest method of producing a duplicate plate from an original.
In comparison with electrotyping, however, it has two distinct disadvantages. One is that it is not adapted for reproducing the fine lines of engravings and type faces. In addition it is comparatively shallow and does not possess a sharp, clean printing face. The other disadvantage is that a stereotype is relatively soft and quickly worn.
Stereotypes have been made more durable, to withstand the wear of printing, by the deposition of a film of harder metal—copper or nickel—on the face of the plate after it has been cast. This, however, is not satisfactory, as it involves not only another operation, but also makes an already shallow printing plate that much shallower and increases the probability of it printing “dirty,” which is one of the chief objections to the stereotype in itself. This practice is not recommended.
ELECTROTYPING
In 1799, Allesandro Volta, of Pavia, in Italy, constructed the first electric battery, which came to be called the Voltaic pile. Improvements in the form of Volta’s battery were made almost immediately by William Cruickshank, in England, who discovered in experimenting with it that he could by its power electrolyze or chemically decompose the salts of certain metals in solution. Both copper and silver, he found, could be precipitated from their salt solutions and deposited upon a plate immersed in the solution.