March 22 (Bloomberg) -- Philanthropist David Rockefeller's decision to auction a dazzling yellow-and-pink painting by Mark Rothko may raise a record $40 million, partly because the work was done at the turning point in the artist's career.

Sotheby's expected price for the nearly seven-foot-tall ``White Center (Yellow, Pink and Lavender on Rose)'' at the May 15 sale in New York would be the highest price for a postwar artwork at auction, the company said. The estimate is nearly twice the $22.4 million Rothko auction record, set at Christie's in 2005.

``White Center'' was painted in 1950, a pivotal year in Rothko's artistic development when he hit upon the abstract style of layered hazy colors for which became known.

``This is a breakout picture,'' said Tobias Meyer, Sotheby's Worldwide Head of Contemporary Art. ``Rothko becomes Rothko.'' The artist's works have sold for $30 million on the private market, according to Meyer.

Rockefeller is selling the picture after prices of modern art have soared. Twentieth-century art prices jumped 61 percent last year and have tripled since 1996, according to Art Market Research's index of the most expensive works by artists including Rothko, Willem de Kooning and Andy Warhol.

``It's a beautiful painting and 1950 is a great date,'' said New York dealer Joan Washburn. ``And it's huge.''

Rockefeller bought the painting in 1960 on the recommendation of the Museum of Modern Art curator Dorothy Miller, who championed Rothko and the other American abstract expressionist artists. Rockefeller's taste tended toward tamer, figurative art. His brother Nelson, who served as governor of New York from 1959-1973, was better known for collecting radical abstract expressionist artworks.

`Reluctance and Trepidation'

``Dorothy Miller told me about it and urged me -- if not insisted -- that I acquire it,'' Rockefeller said in a statement provided by Sotheby's. ``So it was with some reluctance and trepidation that my wife, Peggy, and I added `White Center' to our collection.''

Rockefeller, 91, is honorary chairman of MoMA's board of trustees. His mother, Abby Aldrich Rockefeller, was one of the museum's original founders in 1929. Two years ago Rockefeller pledged $100 million to the museum, the largest gift it has received. MoMA owns 11 Rothko paintings. Sotheby's has guaranteed the painting, which means that Rockefeller will receive a mutually agreed upon amount regardless of the sale's outcome.

(Lindsay Pollock writes on the art market for Bloomberg News. The opinions expressed are her own.)

To contact the writer of this story: Lindsay Pollock at lindsaypollock@yahoo.com

Last Updated: March 22, 2007 03:21 EDT