Several Los Angeles artists at Culture Day at LACMA (L.A. County Museum of Art), 1968. Photo by and © Julian Wasser.

Artists outside the Ferus Gallery in Los Angeles, 1959. Clockwise from top: Billy Al Bengston, Irving Blum, Ed Moses, and John Altoon. Photo by William Claxton. Courtesy Demont Photo Management, LLC.

Irving Blum with Andy Warhol's Campbell's Soup Cans at the Ferus Gallery in Los Angeles, 1962. Photo by William Claxton. Courtesy Demont Photo Management, LLC.

Peter Alexander in 1966. Image courtesy of and © Billy Al Bengston

Melvin Edwards in January 1965. Image courtesy of Melvin Edwards

Poster for Karl Benjamin exhibition at the Esther-Robles Gallery in Los Angeles, 1964. © Karl Benjamin. The Getty Research Institute, Gift of Michael Asher, 2009.M.30.12

Protest on La Cienega Boulevard, outside the Ferus Gallery, May 15, 1965. The Getty Research Institute, Charles Brittin papers, 2005.M.11. © J. Paul Getty Trust. Photo by Charles Brittin

“Artists Against Escalation” protest at LACMA (Los Angeles County Museum of Art), May 16, 1965. The Getty Research Institute, Charles Brittin papers, 2005.M.11.32. © J. Paul Getty Trust. Photo by Charles Brittin

Rani Singh of the Getty Research Institute and Jack Brogan, conservator, inspect De Wain Valentine's Red Concave Circle in Brogan's studio in Inglewood, California, June 17, 2011. © De Wain Valentine

Llyn Foulkes stands by his work Flanders (1960–62) at the opening of his solo exhibition at the Pasadena Art Museum, September 18, 1962. Image courtesy of and © Llyn Foulkes

John Altoon smoking, ca. 1963. Image courtesy of Larry Bell. Photo by Dennis Hopper and © The Dennis Hopper Trust

Betty Asher and Henry Hopkins in front of Ed Ruscha's painting The Los Angeles County Museum on Fire (1965–68), ca. late 1960s. © Ed Ruscha. The Getty Research Institute, Betty Asher Papers, Gift of Michael Asher, 2009.M.30

Vija Celmins in her studio in Venice, California, 1966. Photo by Tony Berlant. Art © Vija Celmins

Mary Corse working in downtown Los Angeles in 1966. Image courtesy of and © Mary Corse

Mary Corse working in downtown Los Angeles in 1966. Courtesy of and © Mary Corse