Jenny Uglow at the New York Review of Books:
Freud felt—in a very old-fashioned way—that his portraits somehow got to the essence, the heart of the “self.” Martin Gayford quotes him as saying he wanted a painting not to be “of” or “like” the person he painted: “I didn’t want to get just a likeness like a mimic, but to portray them, like an actor…. As far as I am concerned the paint is the person. I want it to work for me just as flesh does.” After sittings, he liked to talk to his subjects, share a meal, understand their feelings. “In a way, I don’t want the picture to come from me. I want it to come from them.” In practice, this often meant that the person did not exist for Freud apart from the sittings: those who did not turn up, or wriggled, or chattered, or were otherwise annoying, were out—no matter what they gave up to sit for him for so long.
Sitting for Freud often took months while he circled around, came back, altered details, slowly filled in the center and worked outward. Small details, like the light on a lapel, a stray tuft of hair, or a deepening, swirling background, could alter the focus of the whole, and the strength and density came in part from this technique of returning, layering, reworking. The sketches were part of this work, but also a separate expression of the subject that obsessed him at the time. His lasting draughtsmanship shows in the sketch Girl sleeping, while the drastic change in his painting style in the 1950s from flat, almost hallucinatory definition, to loosely-handled watercolors and the lavish, heavy brushstrokes of later oils, is displayed in the loose, fast sketch of Anna in Venice, from the 1960s. Missing here are the naked poses that leave his subjects splayed and open, male and female genitalia rendered with a clinical gaze.