To prepare the plate for etching, it is first polished to remove all scratches and imperfections from the surface. When the surface is perfectly smooth, it is evenly covered with a layer of acid-resistant varnish or wax called primer.
Using a blunt stylus, the etching needle, the printmaker carefully scratches away parts of the primer after the motif, exposing the metal underneath.
Once the entire motif has been drawn into the ground, acid is poured over the plate or the plate is dipped in acid.
The acid eats into the metal only in the exposed areas, creating depressions where the paint can settle. The depth and width of these depressions depends on how long the plate is exposed to the acid: the longer it is exposed to the acid, the deeper and wider the depressions, which absorb more ink and thus bring darker lines to the paper.
This process allows you to create a nuanced tonal palette. To create darker tones, certain areas can be bathed in acid several times, while lighter areas are protected from further acid exposure by covering them with soil. Once the plate has been sufficiently affected by the acid, the printmaker removes the ground with a solvent.
After removing the primer, the plate is ready for inking. In an intaglio process, the ink is held in the incised lines. A cloth ball, cardboard strip or similar material is used to gently spread the ink over the entire surface of the plate; the same material is used to remove most of the excess ink from the surface. The plate is then cleaned with a tarlatan cloth (heavily starched cheesecloth).
As a final measure, printmakers often use their palms to wipe away the last remnants of paint. In certain cases, a printmaker may not clean the plate completely, but leave a thin layer of ink on the plate to create a tone.
Once the surface of the plate is cleaned enough to be satisfactory, the plate is placed ink side up on the bed of a web press. Although some early intaglio prints appear to have been made by simply pressing the paper onto the plate with the hands, in most cases a special press with rollers had to be used to press the paper into the finely cut lines.
Before the plate is moved through the press, it is covered with a sheet of damp paper and then with printing blankets, often made of felt, to relieve the pressure on the metal plate.
As soon as the etching is printed on the paper backing, the motif appears on the plate in mirror image of the original. The pressure of the press not only presses the ink onto the damp paper, but also creates an outline of the outer edges of the metal plate in the paper, which is called a plate impression.