I get chills recalling the sheer power of art that I felt in this room at the National Portrait Gallery, as if the genius loci of Washington, D.C. was standing next to me like a ghost.

Loren Munk is unmissable. Dressed in white bespeckled painter’s pants, this 73-year-old artist shambles into New York’s galleries with a slightly crazed look. He walks around with his little camera, ...