Illustrative matter in a book or other publication, usually printed with or without explanatory text on a leaf of different quality paper than the main text, with the reverse side often blank or bearing a descriptive legend. Plates are usually inserted in the sections after gathering, either distributed throughout the text or in one or more groups. A tissued plate is separated from the facing page by a loose sheet of interleaved tissue paper, usually to prevent offset or rubbing. Click here to see an example from the 19th-century serial publication Godey's Lady's Book and here to see a selection of 19th- and early 20th-century fashion plates in the Digital Collections of the University of Washington Libraries. Engraved examples can be seen in Agostino Ramelli's Le diverse et artificiose machine (Paris: 1588), courtesy of the Smithsonian Institution Libraries.
Because they are not integral to the gathering, plates are excluded from the pagination; however, they are usually numbered in roman or arabic numerals and listed in order of appearance in a separate part of the front matter. In the bibliographic record created to represent an item in the library catalog, the number of leaves or pages of plates is indicated in the physical description area, following extent of text. Compare with cut. See also: color plate, double plate, monochrome plate, and plate number.
Originally, a flat piece of wood or a sheet of metal used to print, emboss, or engrave a design, illustration, or image on paper, vellum, or some other printing surface. In modern printing, photomechanical plates are used to print both text and illustrations. See also: plate mark.
In photography, a rigid, comparatively thick support for the layer of photosensitive material (emulsion) bearing the image. Glass is used for its flatness and where dimensional stability is essential. In the tintype, a thin metal sheet, usually of iron, was used to support the emulsion. Compare with film.