Orange Sweater, one of Cindy Sherman's most iconic photographs, has sold for $2.8m, the second highest price ever achieved by the artist at auction.

Unknown #96, produced in 1981, and featuring the artist in the guise of a young girl, sold at Christie's Post-War and Contemporary Art auction in New York on May 8.

It was consigned by the Akron Art Museum, which parted with the piece in an effort to raise funds for further art purchases.

Cindy Sherman's Unknown #96 sold for $2.8m

Although it can be controversial for institutions to sell their pieces, the Akron is following the guidelines of the Association of Art Museum Directors, which states that museums should only sell pieces if they intend to use the proceeds to buy new works.

Mitchell Kahan, the museum's director, told Ohio.com: "The way I look at it is that it took us 90 years to build up an acquisition fund of $1.8m.

"Suddenly, in one evening, we have more than doubled that. It's an enormous step forward for the museum's capability to buy future works of art."

American photographer Sherman is regarded as one of the most important female artists of her generation. She is best known for her appearance-altering self-portraits.

The sale is confirmation of the strength of the market for Sherman. Last month her Untitled Film Still #21 sold for $746,500, surpassing its high estimate of $200,000 by 273%.

Another print of Unknown #96 became the most valuable photograph in the world in May 2011, when it sold at auction for $3.89m. That record was surpassed in November 2011 when Rhein II by Andreas Gursky made $4.33m.

The May 8 auction also featured a new world record for a piece of contemporary art, Mark Rothko's Orange, Red, Yellow selling for $86.9m.

PFC Auctions has several superb pieces of investment-grade art available in its current auction, which runs until May 24.