One of the things I like least about being a film critic is saying not-too-nice things about projects that represent a lifetime's passion for one of the involved parties. Sadly, such is the case with Julie Taymor's Frida, a motion picture that has been a longtime obsession for producer/star Salma Hayek. In bringing the bio-pic of artist Frida Kahlo to the screen, Hayek had to overcome numerous obstacles, including Madonna and Jennifer Lopez (both of whom wanted to play the role), limited funds that didn't allow her to hire a ghost re-writer (her boyfriend, Edward Norton, did it for free), and conflict with the men holding the purse strings at Miramax Films. The good news is that the movie was eventually made. The bad news is that maybe it shouldn't have been.

If that sounds cruel, well, Frida isn't terrible. It's just disappointingly superficial - a movie that has all the elements necessary to be a fascinating, involving character study, but never does more than scratch the surface. This is biography-of-the-week material, a linear chronicle of the highlights of Kahlo's life beginning in 1922 and ending 30-plus years later. All of the fascinating characters to cross Frida's path are here - muralist Diego Rivera (Alfred Molina), who was the love and the heartbreak of her life; Leon Trotsky (Geoffrey Rush), the famous Russian revolutionary with whom she had a brief fling; and Nelson Rockefeller (Norton), who commissioned Rivera's most famous mural, then had it torn down.

Good acting does not always equate to good characterization. Frida is blessed with several strong performances. Salma Hayek, who gets top billing, is effective in the lead role, conveying the character's strength and toughness while allowing occasional moments of vulnerability. This is not an Oscar-worthy role, but it shows that Hayek is capable of doing much more than she has heretofore been recognized for. (For those who are interested, she shows quite a bit of flesh.) Alfred Molina is terrific as Diego; in fact, his presence is so commanding that he overshadows Frida and made me wonder if the real name of the film should be Diego. The supporting cast list is long and luminous: Ashley Judd, Edward Norton, Geoffrey Rush, Valeria Golino, and Antonio Banderas.

This is the second feature film for director Julie Taymor, who is perhaps best known for her stage direction of Disney's "The Lion King". Although Hayek was the driving force behind getting the film made, Frida's visual dynamics are all Taymor's, from the bright hues that liven up the opening scene to the stylized image of the broken Frida lying on the trolley car's floor (with gold dust all around) to the King Kong recreations with Diego as the big, bad ape. The plot is frequently moribund, but at least Frida is always interesting to look at. However, given the subject material, the result should have been so much better.