The 1960s and 70s were an explosive time in America, riven with protests, violence, and a series of shattering assassinations. But there was also change and hope. The year 1963 saw the founding of the Kamoinge collective of Black photographers, its vision giving momentum to the Black Arts movement. “Kamoinge,” which means “a group of people acting together,” comes from the language of the Kikuyu people of Kenya. A new exhibition collects nearly 150 photos from 14 of the collective’s early members, including such masters as Anthony Barboza, Louis Draper, Herb Randall, and Ming Smith. —J.V.