Aquatint is a technique used in printmaking that creates an image by exposing acid to metal. The process involves etching a design onto a copper plate, which is then treated with acid-resistant resin or wax. Once the desired areas are protected from the acid, the plate is immersed in an acid bath, which eats away at the exposed lines, creating tiny pits that hold ink when printed. This results in a soft, hazy image with varying degrees of darkness and shading. The aquatint technique allows for large areas to be filled with tone without having to hand-etch each individual line, making it an efficient method for producing prints with subtle gradations.