ätzen

Old High German ezzen (to eat) and its causative form äzen (to cause to eat, to feed, to corrode) described the acid's action on metal. The technique of etching was developed in the early 16th century as an alternative to engraving: rather than cutting directly into metal with a burin, the printmaker coated a metal plate with an acid-resistant ground (wax or varnish), drew through it with a needle, then immersed the plate in acid. The acid ate — ätzed — into the exposed lines.

Albrecht Dürer made the earliest dated etchings in 1515-1516, though Daniel Hopfer of Augsburg had been using the acid technique to decorate armor since the 1490s. The etching needle was lighter than the engraver's burin, required less physical pressure, and allowed a freer, more spontaneous line. Artists could draw almost as fluidly as with pen on paper. Rembrandt van Rijn, who made over 290 etchings between the 1620s and 1660s, pushed the technique to its expressive limit.

Rembrandt combined etching with drypoint (scratching directly into the plate, leaving a burr that held extra ink) to produce prints of extraordinary tonal range. His etchings — Three Crosses, The Hundred Guilder Print, Self-Portrait with Cap — showed what printmaking could achieve when drawing and painting merged. His plates changed during his lifetime; he reworked some through multiple states, and surviving prints from different states show the work evolving.

Today etching is practiced by printmakers who value the directness of the acid-drawn line and the intimacy of the limited-edition print. The acid has changed (ferric chloride has largely replaced the more dangerous nitric acid), but the fundamental process — coating, drawing, biting, inking, pressing — remains what it was in Hopfer's Augsburg workshop five centuries ago.