In “The Serial Portrait: Photography and Identity in the Last One Hundred Years,” the National Gallery of Art showcases 153 works by 20 artists who took images of the same people again, and again, and again over time. But it’s far from repetitive. Emmet Gowin’s dreamy, time-lapsed fantasy portrait of his wife is a highlight, as are Milton Rogovin’s gritty urban portraits, a clever transgender trompe l’oeil by Nan Goldin, a selection of mirror-aided images by Ilse Bing, and a self-portrait in which Francesca Woodman looks like a classical column. But most stunning is Gillian Wearing’s homage to Robert Mapplethorpe’s famous final self-portrait, the one with a seemingly disembodied head and his hand holding a skull-topped cane. Wearing’s version looks almost exactly like the real thing, because she was wearing a specially crafted Mapplethorpe mask when it was taken. The theme of “serial portraiture” proves to be pretty amorphous, but the inclusion of projects like Wearing’s make it inspired.

The exhibit is on view 10 a.m. to 5 p.m. Mondays–Saturdays and 11 a.m. to 6 p.m. Sundays to Dec. 31 at the National Gallery of Art, 4th Street and Constitution Avenue NW. Free. (202) 737-4215. nga.gov.