Mezzotint described by Ludwig von Siegen August 1642, in a letter to King William VI (The Mezzotint, Carol Wax) «There is not a single engraver, a single artist of any kind, who can account for, or guess how this work is done, for as your Highness well knows, only three methods of work are recognised in engraving, viz: 1st, engraving or cutting, 2nd, biting with acid or etching; 3rd, a method very little used, executed in small dots made with punches, but which is difficult and so arduous that [it] is seldom practiced.»