How does an artist make an etching on a metal plate?

To create an etching on a metal plate, an artist follows a process of chemical biting to incise a design into the surface.12

The Etching Process

1. Preparation: The artist cleans a metal plate—typically copper, zinc, aluminum, or magnesium—to ensure an acid-resistant coating, known as a ground, adheres properly. The ground, often a mixture of wax, asphaltum, and resin, is applied to the plate in a solid or liquid form.312
2. Drawing: Once the ground is set, the artist uses a sharp tool, such as an etching needle, to scratch the design into the coating. This exposes the bare metal beneath while leaving the rest of the plate protected.12
3. Biting: The plate is submerged in a mordant (acid) solution. The acid eats away the exposed metal, creating recessed lines. The choice of acid depends on the metal: for example, Dutch mordant is often used on copper for controlled results, while nitric acid is used on zinc for a more rugged bite.1234
4. Refining: Artists may develop the plate in stages by using "stop-out" varnish to protect areas already etched, then re-submerging the plate to deepen other lines.3
5. Printing: After removing the ground with a solvent, the plate is inked and wiped, leaving ink only in the recessed lines. The image is transferred to damp paper using an etching press.352