Etching, the art of engraving with acid on metal; also the print taken from the ‎metal plate so engraved. In hard-ground etching the plate, usually of copper or ‎zinc, is given a thin coating or ground of acid-resistant resin. This is sometimes ‎smoked so that lines scratched through the resin will be clearly visible. A needle ‎exposes the metal without penetrating it. When the design is completed, the plate ‎is submerged in an acid solution that attacks the exposed lines. During the bath ‎the plate is frequently removed, and such lines as are bitten to sufficient depth ‎are coated with stopping-out varnish. The lines receiving the longest exposure to ‎the acid will be the heaviest and darkest in the print. It is also possible to apply ‎the acid locally to the plate. In printing, all varnish is removed; the plate is ‎warmed, coated with etcher's ink, and then carefully wiped so that the ink ‎remains in the depressions but is largely or wholly removed from the surface. It is ‎then covered with a soft, moist paper and run through an etching press. There ‎are many variations in the technique of etching. Etchers often remove undesired ‎lines by burnishing and otherwise change the first state of the plate from which ‎they make their trial print. Certain etchings appear in many and widely differing ‎states. Only a limited number of first-rate proofs can be made from a plate, and ‎some etchers destroy their plates after making a given number of prints. Soft-‎ground etching gives effects similar to those obtained in pencil or crayon ‎drawing, while aquatint approximates the effects of a wash drawing. Aquatint is ‎often combined with hard-ground etching, as is also drypoint. This latter ‎technique is not true etching, as no acid is employed; drypoint produces a finer ‎line than does aq¬¬uatint. Pictorial etching evolved gradually from the earlier burin ‎engraving. Both seem to have originated in Germany, where Dürer's etchings on ‎iron, made between 1510 and 1520, were probably the earliest important ‎examples of an art that in the following centuries was practiced by many of the ‎greatest draftsmen and painters. Among the foremost in the history of etching are ‎the works of Dürer, Callot, Rembrandt, the Tiepoli, the Piranesi, Goya, and ‎Whistler.‎

See A. M. Hind, A History of Engraving and Etching (rev. ed. 1963); J. Pennell, Etchers and ‎Etching (1919); A. Gross, Etching, Engraving, and Intaglio Printing (1970); W. Chamberlain, The ‎Thames and Hudson Manual of Etching and Engraving (1978).‎