Typically, the show is a curious and sometimes illogical mix of aspiring artists and old faces. It usually draws the majority of its artists from New York and Los Angeles. It's usually divided between object art and film/video, which requires multiple visits if one hopes to even sample everything.

Those parameters we have come to expect, so the fact that the current Biennial, featuring 81 artists, satisfies the profile is almost reassuring. What we do not expect, however, is for the Biennial to be dull, uninspired, flat, tepid. Such is the case this year.

I can recall being surprised, shocked even, only once - not by Tearoom, a William E. Jones video about gay sex in public toilets, but by three realist paintings of a type as common as pigeons here in Philadelphia. Old-fashioned representational painting in the Biennial? Extraordinary. I can explain it only as a sentimental tribute to the artist, San Franciscan Robert Bechtle, now in his mid-70s, a pioneer of the photorealist movement of the late 1960s and early '70s.

The Bechtle paintings, all street scenes in which empty pavement fills the foregrounds, can be dismissed as an anomaly, but at least they capture one's attention and provoke speculation regarding the artist's intentions.

These paintings make another point about the Biennial, that it's more a bazaar than an exhibition. Like a bazaar, it's excessively crowded, noisy, and randomly organized. (I had the misfortune to visit during school vacation week. Never visit any museum when students of any age are at liberty.)

The only practical strategy is to browse and hope that something will catch your eye. Sometimes this happens for negative reasons, as with the attenuated papier-mache-and-plaster sculptures of Charles Long. These were inspired by, and attempt to replicate, smears of bird excrement that he observed on the concrete embankments of the Los Angeles River.

The frail sculptures, supported by steel armatures, suggest what Alberto Giacometti might have created had he worked abstractly. Are they engaging because of that, or because we know they derive from bird poop?

Because they're striking objects, Long's sculptures can neutralize the Biennial's chaotic ambience, but many other artists whose work is essentially conceptual (even when their ideas are expressed through objects) are less fortunate. It's ironic that the exhibition's entertainment ethos works against these artists. In crowded, noisy galleries, distinctive objects can survive while more intriguing ideas embodied in banal objects tend to be submerged.

This Biennial, like many of its immediate predecessors, contains a high proportion of art about the nature of art, which rarely is as stimulating as art about life. Ellen Harvey's installation of empty picture frames, Museum of Failure, is one example. Alice Könitz's sculptures that reference modernist furniture is another. Such work requires contemplative space and ambience; lacking same, it is easy to disregard.

Videos and films fare better. In a single visit, it's rarely possible to do more than sample and hope that one or two will persuade you to sit for a while. This is random selection at its most pernicious, but in at least one instance it paid off, in a video by Israeli-born artist Omer Fast called "The Casting." It skillfully weaves together two stories involving an American soldier, a romantic encounter with a German woman, and the tragic shooting of an Iraqi citizen at a checkpoint.

The soldier-narrator tells both stories simultaneously as the images shift from a highway in Iraq to one in Germany. Sometimes a single sentence will refer to both incidents as if they had merged in his mind. Both involve stress and anxiety. The stories are incidental; Fast's ability to make such synthesis plausible, to draw parallels between war and peace, give "The Casting" a keen edge.

Visitors possessed of unlimited time and infinite patience might want to try Spike Lee's four-hour-15-minute opus, The Breaking of the Levees, about the Katrina disaster in New Orleans. This exhausting documentary about catastrophic loss and government indifference and incompetence is a major event by itself.

The Whitney needs to develop a way to make the Biennial more visitor-friendly. The show needs either more space or fewer artists. The museum should consider running film/video and object-based art separately, in alternating years. Finally, as a way of continually renewing the series, it might consider inviting only artists who have not previously participated.

Color charted

Art about art receives a more provocative examination at the Museum of Modern Art, where curator Ann Temkin has organized an intriguing exhibition about how some artists have expanded the way they and we should consider color, arguably the single most seductive quality in painting.

Moving beyond the traditional palette, which was already enlarged in the mid-20th century by the invention of acrylic pigments, these artists turned to commercial colors, exemplified by the color charts used by house painters and in auto body shops. The use of these more garish and flamboyant hues dates back at least to the early 1950s, in paintings by Ellsworth Kelly composed, like a color chart, of colored squares.

Temkin includes similar works by other artists, particularly Gerhard Richter and James Dine. Artists who used commercial colors in different ways include Andy Warhol, represented by six of his Marilyn Monroe portraits, and Frank Stella, who painted stripes. Dan Flavin made sculptures of colored fluorescent lamps, and Donald Judd painted his fabricated metal boxes with glossy saturated pigments. The most recent work is a grid of colored dots applied directly to a gallery wall by Damien Hirst.

All these works force us to consider how important color is as an aesthetic signifier. Can a simple "color-chart" composition such as Kelly's Colors for a Large Wall or Richter's 256 Colors really constitute art with an emotional as well as a perceptual dimension? Yes, it can.

This show also prompts us to ponder the psychological effects of particular colors, whether invented or found in nature. It further reminds us that color is one of nature's primary survival stimuli; it leads birds and bees to food and helps other animals to avoid danger. A color chart might seem a simple device, but in a museum it suggests ramifications that you might never have considered.

Art: Biennial Bazaar

The 2008 Biennial exhibition continues at the Whitney Museum of American Art, Madison Avenue and 75th Street, New York, through June 1. Hours are 11 a.m. to 6 p.m. Wednesdays, Thursdays, Saturdays and Sundays, and 1 to 9 p.m. Fridays. Admission is $15 general, $10 for visitors 62 and older and students with I.D. Pay what you wish Fridays after 6 p.m. Information: 1-800-944-8639 or www.whitney.org.

"Color Chart" continues at the Museum of Modern Art, 11 W. 53d St., New York, through May 12. Hours are 10:30 a.m. to 5:30 p.m. Saturdays through Mondays, Wednesdays and Thursdays, and 10:30 to 8 Fridays. Admission is $20 general, $16 for visitors 65 and older, and $12 for students with I.D. Free Fridays after 4 p.m. Information: 212-708-9400 or www.moma.org.