A limited edition etching (also called a line etching) is created by covering a metal plate with an acid-resistant layer of wax called a ground and drawing a design through the ground using an etching needle.
The plate is then dipped in acid, which bites into the exposed lines, thus etching the design into the plate.
After dipping the plate in acid, sections of the design can be stopped out with varnish and the plate immersed in the acid again. This creates a deeper bite, and thus darker lines, for those areas not stopped out. Etching is an intaglio process, so prints made in this manner will have a plate mark. Etching allows for a freer artistic hand than does engraving.
The etching process was invented around the fourteenth century as a method of making decorations on armor. The earliest known printed etching was by Urs Graf and is dated 1513. The technique was perfected in the middle of the seventeenth century by Rembrandt.