Intaglio printing: [in' tal' yoh'] The collective term for several image processes in which prints are made from ink trapped in the grooves of an incised metal plate. Etching and engraving are the most typical examples.

Serigraph: [ser'a graf] A stencil method of printmaking in which an image is imposed on a screen of silk or other fine mesh, with blank areas coated with an impermeable substance, and ink is forced through the mesh onto the printing surface.

Mezzotint: [met' soh' tint'] An intaglio process that is tonal rather than linear. A metal plate is first worked with a curved serrated tool called a rocker, raising burrs over the surface to hold the ink and print as a soft dark tone. The design is then created in lighter tones by scraping out and burnishing areas of the roughened plate so that they hold less ink, or none, in the highlights.

Etching: [ech' ing] An intaglio process in which an etching needle is used to draw into a wax ground applied over a metal plate. The plate is submerged in a series of acid baths, each biting into the metal surface only were unprotected by the ground. The ground is removed, ink is forced into the etched depressions, the unetched surfaces wiped, and an impression is printed.

Mixed media: [mikst' me' de' a'] A technique involving the use of two or more artistic media such as ink and pastel or painting and collage. The various media are combined to create one composition.

Encaustic: [en' kos' tik] The art or technique of painting with hot wax colours that are fused after application into a continuous layer and fixed to a surface.

Casein: [kay' seen'] A paint much like opaque watercolour in which casein, a milk glue, is the binder. Casein is a white, tasteless, odourless protein precipitated from milk by rennin. Casein paint dries quickly with a waterproof surface and may be varnished.

Drypoint: [dri' point] An intaglio printing process in which a pointed needle is used to inscribe the lines. Tiny uplifts of metal, called burrs, are left along the incised line. These burrs result in a soft, fuzzy line in the image when the plate is printed.

Oil paint: [oil paint] A slow drying paint made when pigments are mixed with an oil, linseed oil being the most traditional. The oil dries with a hard film and the brightness of the colours are protected.