Topics in library technology: copying techniques.

Photocopying applications in the library include the combining of previously separate material, the separation of a single item into two or more of its parts, and the selection of parts of existent material by the use of overlays. The production of catalog cards, the creation of sheet material (new book lists, reference bibliographies) from card-form materials, an Index Medicus-derived alerting service, and overdue notices copied from charge cards are among the applications exemplifying these general types. Larger-scale operations employing microfilm are noted. The distinction between copying and printing, in the light of equipment advances, is discussed.