The Museum of Modern Art’s photography department—the oldest of its kind in the US—plans to sell more than 400 works from its collection at Christie’s over the next nine months. The cache is expected to realize more than $3.6 million, and the proceeds will go toward the department’s acquisition fund.

The photographs are by some of the best-known names from the early 20th century to the postwar period, such as Alfred Stieglitz, Edward Steichen, Edward Weston, Man Ray, Henri Cartier-Bresson, and Walker Evans.

Christie’s international head of photographs, Darius Himes, told artnet News that the sale is the result of a longtime review and refinement of the museum’s photo collection. “A lot of photographers whose works are being sold, the museum has in depth,” he says. Others may be duplicates or were deemed not central to a particular body of work.

Henri Cartier-Bresson, Coney Island, New York (1946). Estimate: $50,000–70,000. Image courtesy of Christie’s Images Ltd. 2017.

The photos range in asking price from $1,000 to $300,000, and will be offered in a series of auctions—most of which are online sales—starting this fall and running through spring 2018. (The American Alliance of Museums, the field’s leading professional organization, allows for works to be deaccessioned only when the proceeds are used for other acquisitions.) artnet News reached out to MoMA to ask what artists or genres it intends to target for future photo acquisitions, but had not received a response as of publication time.

Himes said the museum “very much responded to the strategy” of offering the works in online thematic and single-artist auctions. “The success that Christie’s has had with our online platform was something that MoMA really wanted to utilize as a way to draw in and reach a broader collecting audience,” he notes.

Man Ray, Rayograph (1923). Estimate: $200,000–300,000. Image courtesy of Christie’s Images Ltd. 2017.

The selection is led by two unique Man Ray “Rayographs” from 1923 and 1928 that are estimated at $200,000 to $300,000 and $150,000 to $250,000 respectively, and will be offered in the October 10 day sale. “Rayographs” are works the artist made without a camera by placing objects directly on a sheet of photo-sensitized paper and exposing it to light.

Christie’s will preview highlights of the MoMA collection during multi-city tours in San Francisco, Los Angeles, and New York beginning in September.

Himes says the auction house wanted to offer the 400 works “in a digestible way. We have also found that the online platform excels when there are sales on individual artists and also on themes. So this material fit that like a glove.”

Man Ray, Rayograph (1928). Estimate $150,000–250,000. Image courtesy of Christie’s Images Ltd. 2017.

Himes noted that Christie’s online platform now draws the auction house’s largest share of new clients globally.

While the museum made the decisions about what to sell, Himes says his role was to “offer a level of expertise on the marketplace, provide estimates, and talk about how the particular works might perform in the marketplace.”

Though Christie’s has worked with other MoMA departments in the past, this is the first time it has worked with the photographs division. “This is such a rare opportunity for collectors to own a piece of history,” Himes says.