ACQUATINTA. - A method of engraving which, etching (v.) or drypoint (v.), produces various gradations of chiaroscuro very similar to those of watercolour (v.) and pencil and charcoal drawings, by uniformly attacking the desired areas of the copper plate through the action of sulphur powder. Good grain is now commonly obtained by blowing very fine resin powder onto the plate before immersing it in acid; but some use to coat the plate with varnish, sprinkle it with fine salt, and then wash it so that the varnish remains full of tiny holes. Steel-facing the engraved plate ensures its longer durability, but impairs its softness.
This method, much cultivated in Ireland and England in the eighteenth century, lends itself very well to the reproduction of paintings, of which it can render all the softnesses. It has not had frequent applications in the field of sacred art.
blätter nach Caspar David Friedrich, in Zeitschrift des deutschen Vereins für Kunstwissenschaft, 3 (1936), pp. 421-33.