"Lost" treasures the focus of old masters sales

By Mike Collett-White

LONDON (Reuters) - Art treasures either presumed lost or previously dismissed as copies are the focus of a series of old masters auctions in London next week.

Sotheby's and Christie's once again go head to head, having recently broken a series of records with their main summer sales of impressionist, modern, post-war and contemporary art that fetched over $1 billion.

While the old masters sales tend to be smaller, with a more limited pool of works available, the world's two leading auctioneers are offering art worth a combined total of more than $120 million on Tuesday, Wednesday and Thursday.

One of the top lots at Sotheby's is "Portrait of Willem van Heythuysen" by Frans Hals, one of the leading painters of the Dutch Golden Age.

For about 300 years after it was painted in the 1630s, the work was considered an authentic Hals, but was demoted to a copy of another version of the portrait now in a Brussels gallery.

According to the auction house, it disappeared after 1963 before being recently re-discovered and re-instated as a genuine Hals. It is expected to make 3-5 million pounds ($6-10 million).

"The most exciting things are very often the re-discovered ones," said Alex Bell, head of Sotheby's old master paintings in London. He added that the thriving market for other sectors was boosting interest in old masters.

"I've felt more interest in this sale than for a while," he told Reuters.