One of the most widely used methods of printmaking, etching is a technique that uses a chemical action to produce incised lines in a metal printing plate.

It is a form of printmaking known as ‘intaglio’, which is a design that is cut or engraved into another material, where the incised line or shape holds the ink. It is directly opposed to ‘relief’ printmaking where the shapes are cut away and the ink is held on the remaining flat surface (as with a linocut, for instance).

In pure etching, a metal – normally copper, zinc or steel – is covered with an acid-resistant wax or resin ‘ground’ (coating). The image is drawn through the coating with an etching needle, exposing the bare metal. The plate is then dipped in a bath of acid, which ‘bites’ into the metal where it has been exposed, leaving lines sunk into the plate.

The remaining coating is cleaned off the plate, and the plate is inked all over. The ink is then wiped off the surface, leaving only ink in the etched lines, which creates the image on paper when fed through a printing press.

Etching may also be combined with other intaglio techniques, such as ‘aquatint’ (a method of achieving tonal shading using powdered rosin rather than a needle) or engraving. There are many types of etching: ‘soft-ground’, using a non-drying coating to produce softer lines; ‘spit bite’, which involves painting or splashing acid on to the plate; ‘open bite’ in which areas of the plate are exposed to acid with no resist; and ‘photo-etching’, produced by coating the plate with a light sensitive emulsion and exposing this to light to reproduce a photographic image.

For examples of the ways in which etching methods can be adopted to achieve vastly diverse effects, see the immaculately detailed prints of Martin Langford, the softer forms and shapes of Jason Hicklin and the vibrant layers of Louise Davies.