Anthony van Dyck developed a repertoire of hand gestures that he and his studio assistants could apply to portraits, and he employed hand models of both sexes for that specific purpose. This additive approach is hinted at in a proof impression of his portrait of Adam de Coster (left) in which the sitter's right hand is unfinished. The engraver's model sheet either lacked this latter detail or required modification to fit into the print's frame.