Study of Thirteen Heads 1770 Jean Jacques de Boissieu French Boissieu's graphic oeuvre includes several sketch plates such as this one, where an etching needle was used to draw independent sketches directly onto a prepared copper plate. A format originally associated with the learning process and an artist's initial forays into the medium, the sketch plate became, in the hands of Rembrandt and his eighteenth-century emulators, a vehicle for virtuosity. Here, Boissieu covered the plate with sketches, mostly of old men, juxtaposing heads drawn to different scales and with different degrees of finish.. Study of Thirteen Heads 385177