On a thin sheet of copper, which I carefully bevel, polish, and clean, I apply an acid-resistant coating (the ground). Using a rounded needle-like stylus, I draw through the ground, exposing, while not scratching, the shiny surface. I work on location, as I do with painting, and do the initial needling as I look at the scene before me.
When the plate is submerged in a chemical bath (in my process, non-toxic ferric chloride), every mark that I made interacts with the solution, while parts covered by the ground are not affected.
The chemical reaction* causes each exposed line on the copper to become eroded (etched) into a groove.
I apply ink to the plate, and wipe off the surface, leaving ink in the grooves.
On the press, a dampened piece of fine, cotton-based paper is placed on top of the inked plate, protective blankets of wool felt are placed on top, and then squeezed under high pressure between heavy steel rollers.
The pressure forces the paper into the grooves, transferring ink to paper.
Each etching requires the plate being inked, wiped, and printed by hand (no two are exactly the same), and therefore accurately designated an original print (as opposed to a photomechanical reproduction, such as produced via a computer and ink-jet printer. Buyer beware).