N.Y. Auctions . . . Art Buyers Lower the Boom : Art: Bidders appear to be exercising more selectivity--either the result of sophistication or a resistance to ‘difficult’ pictures.

As the curtain falls today on the most lucrative two weeks in auction house history, totaling about $800 million in sales, few insiders seem to doubt that there will be a repeat performance. A new parade of high-priced artworks is already scheduled to go on the block in May at Sotheby’s and Christie’s.

The boom goes on, but the frenzied buying of the past two years seems to have calmed a bit. Buyers at the top level appear to have become “more selective,” according to Michael Findlay, head of Impressionist and modern paintings for Christie’s.

That selectivity, also noted by dealers, can reflect sophistication or, conversely, a resistance to relatively difficult pictures, such as Pablo Picasso’s sketchy painting of a mordant subject that failed to sell Tuesday night. “Death of the Harlequin,” in the collection of philanthropist Paul Mellon, had been estimated to sell for more than $20 million, but bidding stopped at $17.5 million.

This November’s sales brought prices as high as $40.7 million for Picasso’s rose-period self-portrait, “Au Lapin Agile.” They also featured meteoric rises, pushing Willem de Kooning’s record from $3.63 million for “Pink Lady” to $20.7 million for “Interchange,” for example.

But the Picasso did not supplant Vincent van Gogh’s “Irises” as the world’s most expensive painting, as had been rumored. Stunning as the De Kooning sale was, it didn’t have the same impact as the $17-million sale of Jasper Johns’ “False Start” last November. The De Kooning simply replaced the Johns as the most expensive work by a living artist while prices marched higher across the board.

“I only know what I read, but I’m glad to see that a little bit of sense has returned to the market. I’d love to see it cool,” said John Walsh, director of the J. Paul Getty Museum. The Getty paid a record $26.4 million for “Rue Mosnier With Flags” by Edouard Manet, but the Impressionist street scene had been valued at more than $30 million.

Walsh said he thought the museum had paid “a very fair price” in a bullish market. The Getty is the only museum in the world that can compete for such works, but prices are so steep that the Getty has been forced to exercise unexpected restraint. The Manet was the only work that the museum bid on in the November sales, Walsh said.

In contemporary sales, a few artists--Johns, De Kooning, Jackson Pollock and Francis Bacon--continued to change places at the top of the charts. “Two Flags,” the most expensive Johns this season, was valued at up to $7 million and sold for $12.1 million.

At a slightly lower level, there were similar shifts among Andy Warhol, Roy Lichtenstein, Robert Rauschenberg and Mark Rothko. Lichtenstein’s record zoomed from $2.1 million to $5.5 million with the sale of his “Torpedo . . . Los,” Rothko’s jumped from $2.75 million to $3.6 million.

Among contemporary artists whose prices took the biggest leaps were Frank Stella (up from $1.3 million to $5.1 million), Kenneth Noland (from $495,000 to $2 million), Robert Ryman (from $550,000 to $2.3 million) and Richard Artschwager (from $176,000 to $990,000.

While the market boomed for such accessible art as Tom Wesselmann’s Pop nudes and Jean-Michel Basquiat’s graffiti-style paintings, there was also strong interest in Minimalism. Strong sales of contemporary art in the five- and six-figure range suggest that collectors who have been priced out of the prime paintings market are buying heavily--and expensively--at sales of works on paper. The picture is much the same in Impressionist and modern art: A few celebrated artists repeatedly draw big prices, others make startling jumps when particularly desirable pieces come on the market or interest in their work increases, and lower-level sales grow as top-level buyers seem to become choosier.

A disappointing sale of Impressionistic and modern art Tuesday night at Christie’s--where about 25% of the works offered failed to find buyers--sent a chill through the art market and terrified owners of expensive works that were to be sold the following night at Sotheby’s. But Sotheby’s successful auction allayed most fears.

Auction experts base estimates on recent sales of similar works, but such sales can mean different things--that the market has peaked because collectors are satisfied with what they have or that potential buyers who missed earlier will leap at the next one.

Estimates also reflect current--and changing--tastes. Pierre-Auguste Renoir’s Impressionist paintings are plentiful and expensive at auction partly because one Japanese firm, Aska International, seems to be cornering Renoir.

Buyers at Sotheby’s big contemporary sale were 40% Japanese, 35% European and 25% American, according to the contemporary art department.

Despite all this action, has the market leveled off? “If so, it’s a pretty high level,” Sotheby’s chairman John L. Marion said.

In his view and that of other auction house officials, it’s quality that drives the market. As long as high quality art goes on the block, collectors will line up to buy it, according to this theory. And as long as prices rise and tax laws discourage collectors from donating their art to museums, the trend to sell at auction is likely to continue.