LONDON (AP) — Auctioneer Sotheby's says it plans to sell a Rembrandt portrait with a difference: the artist's fingerprints may be preserved in the paint.

George Gordon, Sotheby's co-chairman of Old Masters, says the prints were discovered during examination and restoration of the oil sketch "Study of a Head of a Young Man" several years ago.

Gordon says experts can't be "100 percent sure" the prints are Rembrandt's, but they belong to someone who picked up the painting as soon as it was finished. He says "the discovery of the marks in the original layer of paint .... make their connection to the artist highly credible."

Sotheby's said Wednesday that the painting will go up for sale in London on Dec. 5, with an estimated price of 6 million pounds ($7.7 million).