Etching was used for decorating metal from the fourteenth century, but was probably not used for printmaking much before the early sixteenth century. Since then many etching techniques have been developed, which are often used in conjunction with each other: soft-ground etching uses a non-drying resist or ground, to produce softer lines; spit bite involves painting or splashing acid onto the plate; open bite in which areas of the plate are exposed to acid with no resist; photo-etching (also called photogravure or heliogravue) is produced by coating the printing plate with a light sensitive acid-resist ground and then exposing this to light to reproduce a photographic image. Foul biting results from accidental or unintentional erosion of the acid resist.
Like engraving, etching is an intaglio technique. Intaglio refers to all printing and printmaking techniques that involve making indents or incisions into a plate or print surface which hold the ink when ink is applied to the surface and then wiped clean.