LONDON—Things started off on an ominous note at the Frieze Art Fair today. As collectors on the top tier of the VIP list lined up at 11 a.m., the sound of thunder came intermittently over the fair's PA system, a special project by the Czech artist Pavel Büchler. But by the end of the day, a mood of cautious optimism reigned. Collectors took their time making decisions, rather than snapping up works in a feeding frenzy, as has been the modus operandi for the past several years of this booming market. This year, Frieze’s preview day was more about reserves than sales. And it was also about putting a happy face on things; it was sometimes hard to tell if dealers were being euphemistic or obtuse.  

"It's subdued," said New York and Berlin dealer Robert Goff, who is not showing in the fair.

"It's reserved," said art adviser Sandy Heller. "But that's not so bad. It gives you the ability to contextualize things, to think about their meaning." 

One question on dealers' minds was whether Americans would show up. But New York collectors Susan and Michael Hort were spotted, as were Joel and Sherry Mallin, Jason Rubell, and Adam Lindemann. Asked what implications the credit crisis might have for the art world, Lindemann said simply, "It's a different market. It has its own rules." 

In general, the major players seemed to come out in force. Spotted around the preview was everyone from critic Jerry Saltz to artist Ai Weiwei to design dealer Murray Moss to Todd Levin, adviser to American collector Adam Sender. There were also the requisite celebrity sightings. Actress Gwyneth Paltrow, casually dressed and seemingly free of make-up, made an appearance, as did singer George Michael. Adam Clayton of U2 was spotted with his adviser, deliberating over a €15,000 ($20,190) abstract painting by Stefan Bruggeman at Yvon Lambert.  

Lisa Dennison, a former director of the Guggenheim Museum who is now executive vice president for Sotheby’s North America, said she had been walking around with a group of contemporary collectors from Europe and America and finding that "in the first half hour of the fair, there have been strong sales of both younger and more established artists, from Robert Gober and Louise Bourgeois to Anselm Reyle and Josiah McElheny. It's encouraging." She also said she was seeing a lot of American collectors.

By early afternoon, London and Zurich gallery Hauser & Wirth had parted with a number of works. A painting by Indian artist Subodh Gupta went for €450,000. A painting by Polish artist Wilhelm Sasnal went for €60,000. A triptych by Indian artist Bharti Kher, made from bindi dots, went for €300,000. Paul McCarthy's pastel on paper Mad House Red/Black, made in 2008 but belonging to the "Propo" series (1972–94), went for $375,000, and two editions of an untitled photograph from the "Propo" series (1972-94/2008) for $160,000 each.

If the fair started slowly at the 11 a.m. super-VIP entrance — indeed, some with regular VIP badges instead of the fancy 11 a.m. ones found themselves queuing in the rain at 1:45 p.m. — by 3 or 4 p.m. things were heating up, and by evening the aisles were packed. The energy had changed. 

By that time, crowds were filing past the life-size Antony Gormley sculpture of a human figure standing at the entrance to Paris and Salzburg dealer Thaddeus Ropac's booth. "If you'd asked me this morning, I would say we were preparing for a slowing of the market," said the dealer. "But after 2:00 p.m., it really picked up. Sales are happening less quickly, but we prefer this. The market is going into a soft landing, and that's what we would wish for." He had sold the Gormley for £220,000 and a painting by Georg Baselitz for €375,000, as well as works by Alex Katz and Tom Sachs.

New York dealer David Zwirner said he thought the fair was going reasonably well, all things considered, but his ratio of reserves to sales on the first day had changed from last year: there were more reserves this year. "People are taking their time making decisions," he said. "But now is not the time to put pressure on." Overall, he said, collectors are feeling insecure. But as the day unfolded and they saw transactions, they began to relax.