For these informal etched studies, Rembrandt treated the copper printing plate as though it were a sheet of paper, perhaps even a page in a sketchbook. The image grows from-and criticizes-the tradition of master artists designing prints as model sheets from which aspiring artists could learn to draw. Most such prints showed idealized figures executed in formulaic patterns of line. Rembrandt's approach was based on direct observation and intuitive drawing. His composition appears casual, but in fact he took great care to vary the poses and lighting in each of the studies and to arrange them artistically on the plate. Saskia seems unaware that Rembrandt was taking her likeness. Perhaps she had grown so accustomed to being observed that she took no notice. He took advantage of these unguarded moments to create remarkable personal images.