Typecasting(redirected from Type casting)
Also found in: Dictionary, Thesaurus, Medical.
the fabrication by casting of type and other composing materials for hand composition. Handcasting of type for composition and printing was originally developed by J. Gutenberg circa 1440. In 1838, D. Bruce, Jr., of the USA built the first manually driven typecasting machine, and in 1862, I. Johnson of Great Britain proposed a universal typecaster with a mechanical drive. Type and other composition materials are usually made at type foundries or sometimes at large printing enterprises. However, the production of conventional type is declining because of the increasing use of typecasting compositors and phototypesetting machines.
The preparation of new type consists of the following principal processes: development and approval of the type designs, fabrication of type matrices, casting of characters, and preparation of full sets of characters (fonts). The matrix is needed to form the casting mold and consists of a metal bar, usually of copper, carrying a recessed, nonreverse image of the character. Punches are first fabricated in order to make the matrix; they carry a mirror image of the character in relief and are produced on steel blanks by hand or machine engraving from designs, one for each letter, supplied by the artist. Under pressure in a press, the punch forms a depression in the matrix. The matrix may also be made directly by machine engraving through use of a metal template of the character design.
Typecasting is carried out on automatic typecasting machines. The matrix is placed in the machine, where it forms the end wall of the casting mold. Molten type metal is forced into the mold automatically under pressure. The alloy hardens to produce a piece of printing type. The cooled piece of type is forced from the mold and machined to remove burrs and the tongue. It then goes to the receiving table of the machine. The conditions of casting and processing on the machine must ensure accurate height (25.1 mm) and other casting dimensions as well as a smooth and clean surface. After casting of the required number of examples of a single letter (one matrix will withstand from 20,000 to 80,000 castings), the type matrix is replaced, and the other characters are cast. Depending on the type size, a typecasting machine may produce from 2,000 to 11,000 pieces of type an hour.
The type font is compiled from the cast pieces of type according to special tables that take into account the frequency of use of each letter in texts. The font includes a specific number of uppercase and lowercase letters and the numerals and symbols needed to compose texts in the given language.
The spacing material used to produce spaces within a line is cast on the same machines by using smooth plates instead of matrices. Rules and larger spacing materials are cast on special automatic machines that continuously cast a metal strip, which is automatically cut into pieces of the necessary length. Plastics, such as a copolymer of styrene with aerylonitrile or a polycarbonate, have also been used since the 1940’s to cast large type and spacing materials. The use of plastics lowers the cost of composing materials, reduces weight, increases the life of the materials, and improves working conditions.
REFERENCESTikhomirov, I. V., I. V. Lobanov, and L. I. Bergman. Osnovy slovolitnogo proizvodstva. Leningrad-Moscow, 1936.
Popov, V. V. Obshchii kurs poligrafii, 6th ed. Moscow, 1964.
N. N. POLIANSKII