In etching, the artist covers a metal plate (usually copper) with a resinous substance (or "ground") that is acid-resistant. The artist then "draws" on the ground with a sharp needle. Wherever the needle is applied the ground is removed, so that in an acid bath those exposed lines are eaten away, or etched. The plate is then inked and wiped, leaving ink in the grooves created by the acid. When the plate is placed on damp paper and put through the printing press, the paper is forced into the inked grooves. For each print in an edition, the plate must be re-inked and wiped. For examples of etching, see Erik Desmazières, François Houtin and Gérard Trignac.
For a color etching, the artist will create several plates of the same size (sometimes one for each color, sometimes including more than one color on a single plate). Each plate is a puzzle piece of sorts, containing a specific part of the final image. The finished product is achieved when each plate has been etched, inked and printed (after careful registering) onto a single sheet of paper. See Lynn Shaler's color etchings.
Resist-ground etching is a technique used in particular by contemporary artist Peter Milton. The artist draws an image on Mylar, then transfers the image to a copper plate that has been treated with a light-sensitive (photo-resist) ground, thus preparing the plate for etching of the image. Creating the drawing independent of the copper plate allows the artist not only to etch images at varying stages of a drawing (and combine those into a "collage" of sorts later), but also to save the original drawing when the process is finished.
ETCHING
