The third principal typesetting machine is the Monotype, patented by Tolbert Lanston in 1887 and first produced commercially in 1897. The Monotype makes each character separately, assembling the characters as in hand composition, for which the Monotype characters can be used. Before electronic composition, monotype had an advantage in setting certain kinds of copy, e.g., mathematical and scientific material, where special symbols or other problems may be involved. In intaglio printing, such as the etching and the steel engraving , the design to be printed is lower than the surface of the plate, which is wiped clean before each impression, leaving the incised design filled with ink, which the paper receives. In photogravure the gravure plate is made by a photographic process.
Rotogravure is photogravure adapted for printing by a rotary or cylinder press.
The third kind of printing, lithography , also known as planographic printing, was devised by Aloys Senefelder. Flat stones were the first lithographic plates and are still used, although a variety of thin metal, plastic, and paper plates are now also employed. A drawing is made on the plate with greasy ink or crayon, and water is then applied to the plate. When the plate is inked for printing, the greasy parts accept the ink and the wet parts do not. 9 Collotype, also called photogelatin, is a lithographic process that uses a gelatin-faced plate to achieve the tonal distribution obtained through screen dots in engraving.