After which there are the nonetheless lives—oh, these nonetheless lives! With their witty, jarring, and wholly authentic preparations of the natural and the inanimate, they’re as masterly and timeless as something from Seventeenth-century Holland. (They have been additionally fertile floor for a ton of nice tales, a few of that are documented by legendary Vogue editor Phyllis Posnick, a longtime collaborator of Mr. Penn’s, in her terrific ebook Stoppers.)

“What has been extraordinary for me to see,” says Rosenheim, “is how with every iteration of the exhibition the story modified. He was a extremely lauded artist in his lifetime. He did a number of initiatives. He traveled the world. The truth is, the 1967 footage are a part of an prolonged collection of worldwide investigations of, if you’ll, cultures from wherever they have been.” The Summer season of Love pictures are a very good instance of that: Mr. Penn decamped to San Francisco, establishing a makeshift studio and welcoming within the denizens of town to take a seat for him. “Though he was older when he took these—he was born in 1917, so he’d be in his 50s at that time—he’s very delicate to the rigor inside these communities, of their types and messages. And that comes by way of within the footage. There’s an authenticity of their performances, of their cultures.”