 A "Self-Portrait" (c. 1880) by Cassatt depicts her in the identical hat and dress, leading art historian Griselda Pollock to speculate they were executed in a joint painting session in the early years of their acquaintance.Cassatt and Degas worked most closely together in the fall and winter of 1879–80 when Cassatt was mastering her printmaking technique.Degas owned a small printing press, and by day she worked at his studio using his tools and press while in the evening she made studies for the etching plate the next day.