Anyone who thought the impressionist market had lost gusto in recent years because of the rage for collecting postwar and contemporary art had to gasp just a little when Sotheby’s New York sold Paul Cezanne’s watercolor Nature morte au melon vert in May for an astounding $25.5 million. With five bidders vying for the sun-drenched still life in a boisterous, packed salesroom, the price far exceeded the auctioneer’s estimate of $14 million to $18 million, coming close to the world record for an Impressionist work on paper. (That record, set in the heady late 1990s by Edgar Degas’s 1879 gouache-and-pastel Danseuse au repos at Sotheby’s London in June 1999, was $28 million.)

What was happening? Was the bidding war driven by the rarity of the richly chromatic Cezanne watercolor, once owned by the painter’s original dealer and champion, Ambroise Vollard? Or with so few top-rate Impressionist canvases available either on the private market or at auction, are collectors willing to pay oil-painting prices for works in secondary media? The answer, according to David Norman, Sotheby’s worldwide cochairman of Impressionist and modern art, is a combination of the above, plus a focus on prime examples by recognized artists.

“That sale shows that the market is much more willing to put a tremendous amount of money into a work on paper now,” Norman says, “and that collectors are looking for quality works in whatever medium. It’s easier to sell a $20 million work on paper than an $8 million oil these days.”

Although many observers have been predicting the demise of the Impressionist market for several years, prices for the great late 19th-century masterpieces have done anything but decline, and new collectors are still entering the market looking for works by Pierre-Auguste Renoir, Claude Monet, and the like. “It’s not at all just the older collectors,” says Guy Wildenstein, president of Wildenstein & Company, in New York. “There are a lot of young and new collectors who are buying the Impressionists, but they’re a little more discreet, because they’re not breaking record prices on each picture.”

Aficionados seeking works by Impressionist painters will inevitably be stymied by the limited supply of oils. Wildenstein, whose gallery hosted a much-lauded exhibition of Monet paintings this spring, estimates that, all told, the seven Impressionist painters he considers most important— Monet, Manet, Renoir, Pissarro, Sisley, Van Gogh, and Gauguin—produced no more than 20,000 canvases. Many of them are already owned by museums and therefore, as he puts it, “dead to the market.” Even in the absence of a run on Impressionists, a decent oil from this period by one of these painters will command eight figures.

Newcomers to the market are understandably nervous about shelling out sums of that size. So where should they look for more manageably priced pieces? Dealers and auction house specialists say the answer may be works on paper. The true gems that come up, like the $25 million Cezanne, are breaking records, but they are the exceptions, according to Sharon Kim, head of Impressionist/modern day sales and works-on-paper sales for Christie’s New York. She says you can still buy a good Impressionist work on paper by a major artist for as little as $10,000, up to about $150,000.

The allure of this genre for collectors goes beyond its relative affordability. The growing attraction is partly the result of an emerging awareness of the way these pieces reveal the intelligence of the artist at work—a point brought vividly to life in some recent museum exhibitions. This summer, the Royal Academy of Arts, in London, and the Clark Art Institute, in Williamstown, Massachusetts, jointly staged “The Unknown Monet: Pastels and Drawings.” New York’s Museum of Modern Art is exhibiting “Georges Seurat: The Drawings” through January 7, and the Kroller-Muller Museum, in Otterlo, Holland, is displaying more than a hundred drawings by Van Gogh from its collection until January 27. All three shows examine the role that works on paper played in the development of the artists’ ideas.

“On paper, you get a sense of intimacy with artists, because you’re seeing the immediate result of their working process, as opposed to the canvas, which has been reworked,” says Kim. “When they’re drawing from nature, they’re capturing the moment, and that’s really the point of Impressionism.”

Another force driving the market for works on paper is a new attitude toward building private collections, says Guy Bennett, head of Christie’s Impressionist and modern department. “In the past, you just had to buy oil on canvas, and you might buy the quirky work on paper or sculpture to fill the corner where you couldn’t fit an oil,” he explains. “Today people are telling a story with their collections about an artist or a period, and that story can be broadly defined.”