JOSEPH CONSTANTINE STADLER.
View of Blackfriars Bridge and St. Paul's Cathedral (after J. Farington). 1789/90.
AQUATINT (Italian: acquatinta) is an intaglio process in which the plate is roughened chemically. A polished zinc or copper plate is dusted in a box containing rosin or asphalt powder. The particles precipitate onto the surface of the plate, and while the plate is heated, they fuse to it. The plate is etched several times to produce the image; meanwhile the areas that remain lighter are covered with etching varnish. The surfaces that are to be completely white are covered before etching. The printer's ink penetrates only into the roughened, i.e., etched areas of the plate, and printing produces a rough grainy surface. As a rule, two to four different degrees of darkness are produced in etching the plate; the transitions between lighter and darker surfaces are sharp, and the black surface is not velvety as in mezzotint. To draw the outlines, drypoint, etching, or soft-ground etching are used. The delicate aquatint plate can produce about 100 high-quality prints.