A printing technique based on stencilling, originally used for commercial work but now popular with artists for creative printmaking. The essence of the technique is that a fine mesh screen, stretched tightly over a wooden frame, is placed above a sheet of paper and colour is forced through the mesh with a rubber blade called a squeegee. Usually the screen is made of silk—hence the terms silkscreen printing, which is preferred in the USA, and serigraphy (from Lat., sericum: ‘silk’); however the screen can also be made of cotton, nylon, or metal, so the more inclusive term is useful. There are various ways of applying the design to the screen. The earliest and most basic was to attach a cut-out stencil to it. A refinement of this method is to paint the design directly on the screen with a varnish-like substance that blocks the holes in the mesh. The blocked-out areas form the negative part of the design, the colour being squeezed through the untouched parts of the screen. However, more sophisticated methods enable the artist to create a positive design directly on the screen with a waxy or waterproof medium that is eventually dissolved to allow the ink through only in the parts that have been so treated. Photographic images can be used in the design by shining a light through a transparency onto a chemically treated mesh. Screenprints are almost invariably coloured, a different screen generally being used successively for each colour. The origins of the technique are murky, but it seems to have come to Europe from Japan in the late 19th century. It was not until the early 1960s, however, that it made an important impact in the art world. It was especially favoured by Pop artists, whose bold images were well served by its capacity for strong, flat colour and its relative crudeness of detail (subtle handling is discouraged because of the texture of the mesh). The artist who more than any other put it on the map was Andy Warhol.