The metal plate is protected by a waxy ground to act as a resist. The artist draws through the ground with a point (in Auerbach’s case usually a dart or screwdriver), revealing the bare metal. Auerbach gives the plate to the printer who immerses it in acid, which eats into the metal where it is exposed by the drawing, but is resisted by the waxy ground. The marks are then inked, and the surface of the plate cleaned. A trial impression is printed on paper in a heavy rolling press. The artist decides whether to do more work on the plate, in which case it is regrounded. The printer shows a choice of differently inked proofs to the artist before printing the edition.
Printing ink is squeezed through a fine mesh screen laid directly on top of a sheet of paper. Some sort of stencil or resist applied to the screen (sometimes created photographically) masks areas that are not to be printed. The medium was particularly exploited by major artists in the 1960s, when Auerbach made a set of prints in which a screen made photographically from a painting was combined with another made from a bold line drawing. Auerbach was dissatisfied with his set of screenprints, but their influence can be seen in the use of the bold screenprinted drawing in the Tree at Tretire etchings.