Etching is the technique of using corrosive chemicals like acid to bite into the exposed parts of a copper or zinc plate to produce a design. Artists use burnishers, needles, scribes and other tools to etch fine lines. After covering the plate with etching ink using a brayer (handheld ink roller), the artist makes a series of impressions from the plate using a printing press.
Drypoint is a technique similar to etching, except that it does not involve the use of acid. Artists use carbide-tipped or diamond-pointed needles to incise the image onto a plate. Because there are no chemicals to corrode the surface, drypoint plates can be made from a variety of materials other than copper and zinc. As with etching, an artist can make a series of drypoint prints from an inked plate using a printing press.
Aquatint is the technique of using acid in conjunction with an acid-resistant powdered resin that bites into unprotected areas of a copper or zinc plate to create tonal effects. The varying degrees of tone are achieved by manipulating the acid exposure to the plate. Artists use etching tools to incise fine lines. As with etching, the artist pulls a series of impressions from the inked plate using a printing press.
Mezzotint is a technique similar to aquatint, in that it creates tonal effects, but it is more precisely related to drypoint since no acid is used. The varying degrees of tone are achieved by roughening the plate with countless little dots using a toothed instrument called a rocker. These dotted indentations in the plate retain ink, which transfers to the finished print. As with etching and other intaglio techniques, an artist can create a series of mezzotint prints from an inked plate using a printing press.