The San Francisco Museum of Modern Art has acquired a group of 40 dye-transfer prints by William Eggleston, reports the New York Times. Dating from 1969 to 1971, the portraits, still lifes, and landscapes capture life in places like the South.

Joshua Holdeman, a 20th-century art expert at Christie's, sold the prints, which were first shown at New York's Museum of Modern Art in 1976.

“Until Eggleston, color photography was not taken seriously,” SFMOMA director Neal Benezra told the Times. “It was the stuff of fashion.” He added, “This group really strengthens our collection of contemporary photography, giving it a great context.”

Neither Christie's nor the museum would say how much was paid for the works, which experts estimate are worth about $4 million.