Tiny imperfections in an old painting found in a closet of a small West Newbury, Mass. church are hardly noticeable to an amateur's eye.

But to the studied gaze of John K. G. Shearman, a Harvard art historian, they are tantamount to reasonable doubt that the painting is entirely the work of an old master.

Shearman, who is Adams University Professor, disputes the claim by art experts and auction house officials that the painting, Madonna and Child, is entirely the work of Andrea del Sarto, a Renassiance master in Florence.

Madonna and Child is definitely a product of del Sarto's studio, Shearman admits--but much of the colorful painting was likely composed by one of del Sarto's assistants, he said.

The work hung in the choir stall of the All Saints Episcopal Church in West Newbury until about 20 years ago. It then found its way into a coat closet. Though church elders knew of the painting, they did not know of its value. So it collected dust.

Last year, in need of money to renovate, the church called two high-end New York auction houses, Sotheby's and Christie's, to evaluate the painting.

Anthony Crichton-Stuart, who directs the "old master" paintings department at Christie's, traveled to West Newbury to investigate.

"I thought this was a most interesting painting, probably from del Sarto's studio but with condition problems," Crichton-Stuart told the New York Times.