The rock star's life, one would think, would spare previous little time for endeavors in other art forms (presuming, of course, that rock music is an art form). True, some rock stars - David Bowie, Sting, Roger Daltrey, Mick Jagger - have dabbed in movies, but that has never been considered unusually adventurous. The cinema is dynamic, larger than life, a bombardment of sound and pictures - a perfect medium for the rock star mystique.

It is for precisely the opposite reason that, for the most part, rock stars have stayed clear of "higher" art forms, which demand more time, discipline and, it could be argued, introspection. Literature finds its way into rock (Sting's allusions to Arthur Koestler and Jung, for example) mostly in the form of name-dropping. The actual writing of books, for one thing, is too time-consuming. But more significantly, the purely literary does little to enhance the iconography of rock stardom. And speaking of iconography, static visual art also has never been a favored avocation of rock musicians. The brush and palette, like literature is too slow and methodical (and silent) a form of expression for pop musicians, who are used to electronic instruments on records and the immediacy of audience response on stage. And, if you are superstar enough, you can always commission Andy Warhol or Robert Rauschenberg to design an album cover, as the Rolling Stones and Talking Heads did.

The best evidence of the scarcity of so-called rock art is currently in the Geodesic Dome at the Canadian National Exhibition. To begin with, the Museum of Rock Art, at the Ex until Sept. 5, isn't really a museum of art at all. There are a few prints and originals, but most of the 384 pieces on display are photographs and rock concert posters - the former nothing more than what millions of rock fans see every week in magazines, and the latter of interest only as curios from the hippie era.

Most visitors to the museum will have no doubt already seen countless photos of Jim Morrison, Janis Joplin, Keith Richards, Mick Jagger and Peter Townshend. They will find nothing new here. And to have missed the series of pictures by Beatles chronicler Dezo Hoffman one would have to have been in a coma since 1964. Indeed, once in the museum, it quickly becomes apparent how superfluous most of the exhibit is; photographs of The Beatles and Rolling Stones are so ubiquitous that it's unnecessary to gather together a few hundred pictures under one roof.

For anyone expecting something from this show, disappointments and annoyances will come in spades. Linda McCartney's photographs, advertised as part of the exhibit, seem to have been left behind at the Museum of Rock Art in Los Angeles, the benefactor of the Ex show and five times bigger. Also, one doesn't have to be a David Bowie fan to notice the unpardonable error under a photograph of Bowie by Tom Nyerges. The photo is clearly of the Thin White Duke, the elegant Bowie of the last few years. But beneath the picture it says: "David Bowie at Monterey Pop Festival, 1968." First, Bowie did not perform at Monterey (he was hardly known in 1968). Second, in 1968, Bowie was undergoing his metamorphosis from curly-haired minstrel to kinky long-hair (the Thin White Duke image wouldn't emerge until 10 years later). And third, Monterey Pop took place in June, 1967 - not 1968.

If that blunder can be forgiven, some of the posters on display might be of interest as artifacts of history, such as the original Woodstock poster with the slogan "3 Days of Peace & Music." The concert lineup on the poster is particularly interesting because of the groups listed that didn't make it to the movie: Janis Joplin, Johnny Winters, Jeff Beck, Creedence Clearwater Revival and Iron Butterfly. Other concert posters from the sixties - designed in the hippie style of fat, distorted lettering and paisley squiggles - are also curious time pieces from the psychedelic era. But it doesn't take long before the eyes begin just passing over the posters quickly, looking for the names of groups and that's about it.

The best part of the show is the few - very few - pieces that can be classified as visual art. Of the prints, an acrylic painting by Joni Mitchell and a color sketch of comedian John Belushi by Ronnie Wood stand out (there are also prints of paintings by guitarist John Mayall, Cat Stevens and Klaus Voorman, the session bassist and artist who drew the cover of the Beatles album, Revolver). Miss Mitchell's painting, called Charlie Down In Mexico (1978), is a man sitting in a wheelchair, his back turned to the viewer, and wearing a wide-brimmed panama hat, facing an empty lawn and woods off in the distance. The painting conveys a sense of affection and loneliness that's in many of Miss Mitchell's sentimental songs about men.

The sketch of Belushi by Ronnie Wood, the newest member of the Stones who used to pay with Rod Stewart, is remarkable in that it reveals the tragic side of the late comedian's personality even though it was done a few years before Belushi's death. Called Belushi on Plane Killers (1978), the sketch doesn't show the hilariously funny grimace; this is the sad, frazzled and despondent Belushi. With his shirt undone to reveal a bulging paunch and his hair messed up, this is the Belushi killing himself with drugs as he eventually did. Indeed, the title, although somewhat ambiguous, makes a definite reference to drugs.

The only original pieces in the museum are three drawings by John Lennon. They are from the 16-piece Bag One collection, which were drawn in 1971 when Lennon had become something of a sideshow with his outlandish peacenik antics, such as getting into a large white bag with Yoko or staying in bed for several days. Lennon was also a compulsive doodler, and the Bag One collection is a series of large-scale doodles. The three drawings at the museum - two erotic drawings and one portrait of himself and Yoko - are not brilliant works of art, but Lennon never intended them to be. Indeed, they are of more interest because they are originals by John Lennon.

But the few pieces that can properly be called art are small compensation for the hundreds of photographs that one doesn't have to visit the museum to see. As might be expected, the Museum of Rock Art is really more of an audio event than a visual exhibit. Sony, the museum sponsor, has an artillery of hardware on display - Walkman cassette players, digital compact discs, headphones, Beta cassette machines - which visitors can examine and test. And the rock videos that play constantly on several screens, pumping music throughout the domed gallery, are more of an attraction than the visual art. Rock is about music; to get rock fans to look at pictures, there has to be sound, too. And, without the videos, the silent pictures at the Museum of Rock Art are little more than what anyone can see in the daily diet of the mass media.