Giovanni Marco Pitteri (1702-1786) used an unusual technique of parallel etched lines. He produced changes of tone by varying the quality of the etched lines through exaggerating their raggedness in places. He gives greater or lesser emphasis to the line depending on whether it depicts an area of shade or light. An etching is drawn with a needle into an acid-resistant coating covering the printing plate. The plate is then immersed in acid to bite the lines where the metal is exposed.