A'quatint, a method of engraving on copper. The outline of the picture is first etched on the plate, which is then thoroughly cleaned and re-covered with a thin layer of etching ground. When dry, the parts to be aquatinted are carefully painted over with a mixture of olive oil, lamp black and turpentine, which is laid on with a hair pencil. This mixture dissolves the etching ground over the parts of the plate to which it has been applied. The plate is then wiped dry and a light coating of finely powdered resin or mastic is sprinkled over it. When the surface is evenly covered the superfluous resin is shaken off, and the plate is gently heated until the resin melts and adheres to the cleaned metal. In melting, the grains of resin run into small granules, leaving minute portions of the plate uncovered. A weak solution of nitric acid is then poured over the plate and corrodes the portions between the granules of resin. When corroded sufficiently to form light shadows, the process is stopped and the plate is cleaned and re-covered, when the process is repeated for the next deeper shades. By continuing the process, any number of shades desired can be brought out. See ENGRAVING; ETCHING.