During the letterpress era, moveable type was composed by hand for each page. Cast metal sorts were grouped into words and lines of text and tightly bound together to make up a page image called a forme. All letter faces were set to the same height, to form an even surface of type. The forme was mounted in a machine press, inked, and an impression made on paper.
The diagram at right shows a cast metal sort: a face, b body or shank, c point size, 1 shoulder, 2 nick, 3 groove, 4 foot. Wooden printing sorts were in use for centuries in combination with metal type.
Copies of formes were cast when expecting later printings of a text, freeing the costly type for other work. In this process, called stereotyping, the entire forme is pressed into a fine matrix such as plaster of Paris or papier m&Atilde;¢ch&Atilde;© called Flong to create a positive, from which the stereotype forme was cast of type metal.
Hand composing was rendered commercially obsolete by continuous casting or hot-metal typesetting machines, such as the Linotype machine and Monotype at the end of the 19th century. The Linotype, invented by Ottmar Mergenthaler, enabled one machine operator to do the work of ten hand compositors by automating the selection, use and replacement of sorts, with a keyboard as input. Later advances, such as the typewriter or computer, pushed the state of the art even farther ahead. Still, hand composition and letterpress printing did not fall completely out of use. Since the introduction of digital typesetting, it has seen a renewal as an artisanal pursuit. However, it is a very small niche within the larger typesetting market.