These are but a few arts-related images drawn from “Identity and Affirmation: Postwar African-American Photography,” an exhibition of 125 images produced by Los Angeles African-American photographers during the postwar years from 1945 to 1980. The marvelous show, at Cal State Northridge, which also includes social and political photographs, is part of Pacific Standard Time survey of post-war L.A. creative undertakings. [...]