Larry Bell in his studio in Venice, California, 1969. Image courtesy of Malcolm Lubliner and Craig Krull Gallery, Santa Monica. © Malcolm Lubliner

Craig Kauffman, ca. 1955. © The Estate of Craig Kauffman. Photo by Ed Moses

Poster for the exhibition War Babies at Huysman Gallery in Los Angeles, May 29–June 17, 1961. Poster created by Jerry McMillan and Joe Goode. Photo © Jerry McMillan. Design © Joe Goode. The Getty Research Institute, 2006.M.1.5. Image courtesy of Jerry McMillan and Craig Krull Gallery, Santa Monica

Edward Kienholz in 1958. Image courtesy of Marvin Silver and Craig Krull Gallery. © Marvin Silver

Peter Voulkos, John Mason, and Paul Soldner at Otis Art Institute (now called Otis College of Art and Design) in Los Angeles, 1956. Image courtesy of Soldner Enterprises and Stephanie Soldner Sullivan

Helen Pashgian working in her studio in the 1970s. Photo by Walt Mancini. Courtesy of and © Helen Pashgian

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

Helen Pashgian polishing one of her sculptures in the Baxter Art Gallery at the California Institute of Technology in Pasedena for an artists in residence exhibition, 1970. Courtesy of and © Helen Pashgian

Melvin Edwards in January 1965. Image courtesy of Melvin Edwards

Announcement for Frederick Eversley exhibition Colored Parabolic Space at the Quay Gallery in San Francisco, 1971. © Frederick Eversley. The Getty Research Institute, Gift of George Herms, 2009.M.20

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

Two Gray Walls, 1975–76, De Wain Valentine. Cast polyester resin. © De Wain Valentine. Photo courtesy of De Wain Valentine

Larry Bell’s studio in 1970. Photo by Larry Bell. Image courtesy of Billy Al Bengston

Slideshow: De Wain Valentine’s process of creating Gray Column, 1975–76. © De Wain Valentine. First, 4th, 5th, 6th, and 8th photo by and © Cathy Weiner; 2nd and 3rd photo by Sean Valentine

De Wain Valentine and two of his studio assistants, Chris D'Arcangelo (left) and Keith Anderson (right), 1975–76. Photo © Cathy Weiner