PERTHSHIRE, Scotland—The Jack Vettriano sketch Singing Butler sold for £39,650 ($73,120) last night, almost double its high estimate, at Sotheby's annual sale of Scottish pictures at the Gleneagles Hotel in Perthshire, reports Bloomberg.

Vettriano completed the 15-inch-high sketch, which depicts a dark figure holding an umbrella over a dancing couple, in an hour, during a master class he taught in 1993. St. Andrew's University consigned the work, estimated at £15–20,000, with proceeds to benefit charity; it was purchased by a U.K.-based private collector. A larger-scale version of the work sold for £744,800 with fees in 2004. Since then the market for Vettriano has become ''a bit more sensible,'' Andre Zlattinger, Sotheby's head of Scottish art, told Bloomberg before the sale.

Overall the auction missed its £6 million estimate, bringing in £4.9 million; 54 percent of the lots sold.