Tonight, to celebrate its upcoming sale of Postwar and Contemporary art, Sotheby’s is hosting the Art Party, an invite-only fête co-sponsored by the Whitney Museum and BCBG Max Azria. Between the champagne and canapés, it’s entirely possible that a guest will spy a painting and decide he has to win it at tomorrow’s auction. But more likely, buyers in his market already know full well what they’re bidding on— and the auction house helped them decide.

With the global art market booming, auction houses today are in a blood-sport battle for dollars. To win, they cultivate potential buyers with levels of personal service that can be as simple as taking a collector to a museum or arranging a private viewing. But no matter what the service, it creates a feeling of separation from the rest of the buying crowd.

At the highest level, that includes auction experts bringing paintings into a collector’s home. “One of the quite common things we do in advance of the sale is that we call the most likely buyer and we offer to bring the work to their home,” Christie’s Deputy Chairman and International Director of Postwar and Contemporary art, Laura Paulson, said.

The visit may last only a few hours, or it could last overnight — so that the potential owner can go to sleep, wake up, and see the work in the morning. Security personnel travel with the painting, and the seller must approve of the transport. As of this writing, out of the 78 lots in the Christie’s contemporary sale on Wednesday, six works have already been seen in private homes.

For this service, newbies need not apply. “They’re previous buyers, and they’re very sophisticated. They fully understand the seriousness of their collection,” Ms. Paulson said.

That seriousness also means they are not just hoping to see how the painting fits in with the décor. As the co-chairman of Sotheby’s Impressionist and Modern Art department, David Norman, said: “In the home, it’s about, ‘Will it belong in my collection? How does it integrate into the rest of the collection?'”

At the end of the day, are buyers so taken with it that they’ll bid at any price? Mr. Norman says the visit can go either way. But even if it doesn’t seal the deal, if a specialist flies cross-country the night before an auction to give a collector that last-minute look, there’s a dual connection that’s made. “It has made a tremendous amount of difference. It can endear them to you. There’s not a sense of obligation, but it makes the client feel special,” Ms. Paulson said.

And it connects the bidder to the work: “They had that emotional relationship instead of seeing it in a sale room,” Ms. Paulson said.

The placement of a work in a private home — even for a short period — “used to be more common in galleries and less so in auction,” the 27-year veteran Ms. Paulson said. “That’s changed now that collectors have become more competitive.”

Mr. Norman, who has been in the business for more than 22 years, also indicated that the at-home service is in response to a shift in the industry. “When I started in 1985, auctions were a wholesale outlet to the trade and knowledgeable insiders,” he said.

Today, it’s about service and the education. “We spend a lot of time talking and educating. I might bring people to a museum to try to make a context for a painter,” he said. “I send people books all the time. In advance of the sale, I send a package.”

For the rest of the public, the auction houses typically create a viewing area where anyone can see what’s on offer. But even then, “People will come in before the public preview,” Mr. Norman said. “I’ll sometimes take curators, art advisers, or collectors through for a quick personal walk. People want to see the work without being observed.”

The houses also send works on tour to increase interest in cities including London, Paris, and Hong Kong. It’s a challenge to the New York staff, which needs the works on hand before the sale. But as Ms. Paulson puts it: “With the new global appetite and new generation of buyers, its important to show our commitment to them. It’s way to learn more about the new collectors.”

Sotheby’s is approaching that global appetite with a new feature on its Web site, My Sotheby’s, which allows collectors to receive alerts when an artist is coming up for sale and look at price histories for paintings. “There is such a big audience out there. This way, people can interact and get information,” Mr. Norman said.

For some, it may be enough to see a digital image. “When someone is a serious art collector, they know what they want. So a big part of it can be done over the Internet,” a Miami-based real estate mogul and collector, Craig Robins, said.

Still, Mr. Robins, who says he attends public previews but never the auction itself, is an eyes-on collector whose approach is what the specialists are looking for: “I don’t like to buy anything without seeing it.”

pcatton@nysun.com