Etching is an intaglio printmaking process in which the design is worked onto a copperplate through a protective, acid-resistant ground, usually with an etching needle. The plate, still covered with the ground, is then dipped into an acid bath, which corrodes the exposed areas and creates furrows and troughs that will hold the ink. The depth of the etched lines is controlled by the strength of the acid and the amount of time the plate is exposed to it. After the ground is cleaned off, ink is spread over the surface of the plate and then carefully wiped off until it remains only in the etched lines. The ink is transferred from the incised lines to the sheet of paper by means of a printing press.
An intaglio technique whereby marks are bitten into the metal plate by chemical action. The plate is coated with a ground (either hard or softground) impervious to acid through which the artist draws to expose the metal. The plate is then immersed in an acid bath until the open lines of areas are sufficiently bitten. Finally, the ground is removed and the plate inked and printed. Etching is commonly used in combination with drypoint, aquatint, and other intaglio processes.