As the world’s chief auction houses scale back in a grim art market, one auctioneer is taking the opposite tack.

Phillips de Pury & Co. is adding 18 new sales of contemporary art to its calendar over the next year and a half. At a time when Christie's has trimmed sales and Sotheby's has shrunk some once-hefty catalogs nearly to the size of CD cases, Phillips, the third-largest auction house for contemporary art, is enlarging its catalogs and tripling their print runs. Prices for contemporary art have plunged as collectors turned to tried-and-true Old Master paintings and Asian vases, but Phillips is placing some of its biggest bets yet on the volatile category. On Sept. 26, it will hold a London auction called "Now," featuring many artists who have never sold at auction before.