Etching

A printmaking technique in which an artist scratches a design through a protective wax coating on a metal plate, then bathes the plate in acid so it bites the exposed lines into the metal, producing a printable image.

Etching gave painters a much freer, more drawing-like line than the older technique of engraving, since cutting through soft wax with a needle is far closer to sketching with a pen than gouging directly into hard copper. That freedom is a large part of why Rembrandt, who produced roughly 300 etchings across his career, treated the medium as a genuine second art form rather than a reproductive afterthought — his etched lines have the same searching, exploratory quality as his drawings.

Because a single etched plate can be re-inked and printed many times, the technique also let images circulate far beyond what any painted original could reach — an etching sold for a fraction of a painting's price could still carry an artist's composition, and reputation, into homes and print shops across Europe.