On a copper plate, which I bevel, polish, and clean, I apply a coating (the ground). Using a special needle, I draw through the ground to expose the metal beneath.
When I submerge the plate in a mordant (ferric chloride), a chemical reaction* causes the exposed metal to be etched.
Another technique I use is drypoint, in which grooves are scratched directly into the plate with a sharp tool.
When ready to print, I roll ink onto the plate, and wipe it off the surface, leaving ink in the grooves.
On the press, high-quality paper is placed over the plate, protective felt blankets over that, and all squeezed (pulled) under high pressure between heavy steel rollers.
Each etching needs to be inked, wiped, and printed by hand; it is designated an original print (as opposed to, for example, a photomechanical reproduction produced by an ink-jet printer).
* FeCl3+Cu+H2O=FeO+CuCl3+H2