Printing

Conventional typesetting machines mold type from molten metal, in a process called type casting, for each new printing job. Casting type is more efficient than setting type by hand. Cast type can be melted down, and reused. Typesetting machines either cast an entire line of type at once (linotype machines) or a single letter at a time (monotype machines).

James O. Clephane and Ottmar Merganthaler developed the first commercially successful linotype machine in 1886. Their machine cast type five times faster than an individual could set type.

The linotype machine was operated by a compositor. This individual worked in front of a keyboard. The keyboard consists of separate keys for each letter, number, or punctuation mark found in a case of type. The text to be set, called the copy, is placed above the keyboard. The compositor keys in the text, character by character. Each time a key is touched, a small letter matrix drops into a slot.

When the compositor has filled in the first line of type, he sends it to a mold. Molten metal is then forced into the mold to produce a metal bar with a whole line of letters in relief. This cast line is then dropped down into the galley, and the process is continued until all the copy has been set.

The advantages of monotype begin to show up with reference works and scientific publications, where complicated tables, punctuation, and figures may have to be inserted. With monotype, corrections can be made by hand without resetting the entire line.