This is an etching process in which the artist is principally concerned with tone rather than line. For this technique a plate is covered with particles of acid resistant material such as resin, then heated to make the particles stick. The treated plate is then placed in an acid bath which bites into the copper which is exposed between grains of resin, yielding composition marked by texture and tone.

Detail of David Boyd's aquatint etching 'Dreamer on the Cliff"