On the weekends and in the evenings in 1949–50, Penn photographed a series of nudes. Drawn to fleshy models whose corpulent undulations he captured in close-up, he printed them using experimental techniques, bleaching and redeveloping the prints until they took on an ethereal quality. With this project, Penn approached photography with principles that ran counter to the glossy sleekness required of magazine pages.

He also photographed nudes at various other points in his career: the San Francisco Dancer's Workshop in 1967, a series of bathing nudes in the late 1970s, and a number of others in the 1990s.