Another important element affecting both popularity and art world approval is subject matter. Kahn makes landscapes. As Susan Shatter, president of the National Academy of Design, which was founded in 1825 by landscape painters and where Kahn is a member, points out: “Landscape painting doesn’t interest critics; it’s too traditional. No one cares about real nature right now, so Kahn is coming from another world.” She adds that “photography has sucked up much of the landscape,” diverting the eye from painting.

Kahn has always been a colorist, employing a palette for his depictions of mountains, rocks, rivers, oceans, fields and the buildings associated with them—especially barns—that is so ravishing that nature at its gaudy best pales beside its hues. His style is impressionistic, and the resulting paintings are luminous, vividly bright and yet entirely serene, even dreamlike.

A defining fact of Kahn’s career, and of the careers of other artists at his level, is that our culture has made a commitment to the edgy and the iconoclastic at the expense of the beautiful. Beautiful has become equated with trivial.

The volume of an artist’s output also helps determine his reputation. Kahn is prolific, producing new works regularly, season after season. “Bonnard’s dealer told him he painted too much,” Kahn says. “I paint too much.” He laughs. “My productivity has been increased by success. When you have the wind in your sails, you forge ahead faster. I don’t golf, play ball, watch television or use computers, so I paint.” On one hand, this may discourage people from competing too urgently to buy a work, because others will soon be available. On the other hand, it’s a boon to collectors to find a good supply always available.

Critical approbation, too, can affect how fervently the market embraces an artist. Does Kahn just lack a forceful champion—a present-day Clement Greenberg—to catapult him into a new league? Margaret Kaplan, editor at large at Harry N. Abrams, Kahn’s publisher, says that although “it used to happen that a critic could turn an artist’s career around,” this doesn’t occur nowadays, either because the art world has become so large that critics’ voices are lost or because they choose to stay out of the fray.

Doyle’s Porcher, however, believes that having an advocate helps. Avery, for example, started selling well only about 10 years ago, a turnaround Porcher attributes partly to the tenacity of Sally Avery, who worked tirelessly for her husband’s career. A measure of Avery’s success: One of his oils, The Reader and the Listener, 1945, sold for $2.5 million at Sotheby’s on November 28, 2007.

Kahn has little patience with handicapping the auction market, especially Avery’s. “He was very quiet and laconic,”Kahn says. “He painted a painting in the morning and another in the afternoon. He didn’t agonize. He figured some would turn out good, some wouldn’t. The public would decide.”

Artists’ careers can be rejuvenated when their works are shown in a new context. “Bob Rosenblum did the Norman Rockwell at the Guggenheim [2001–2] and caused a big controversy,” Kaplan says. “Paul Gottlieb [then of Abrams] talked Carter Brown at the National Gallery into doing the Andrew Wyeth ‘Helga’ show, which was heavily criticized.” The exhibition toured from 1987 to ’89, and the Abrams book sold more than 500,000 copies. In both cases, attention was paid, bringing the artists back into the limelight. Wyeth hit a high of $10.3 million at Christie’s in 2007 for Ericksons, 1953, and has exceeded $1 million seven times since 2000, while Rockwell made an artist’s record of $15.4 million for Breaking Home Ties, 1953, at Sotheby’s in 2006.

Instead of critics, curators and spouses, the star makers in the 21st century are more likely to be publicists coupled with aggressive gallery owners who represent artists with sensational presentations. Jeff Koons’s flowering puppies or Damien Hirst’s sushied sharks and diamond-studded skulls catch the public’s imagination quicker than a quiet if masterly painter.