Even by Wong’s standards, the film has a dreamy midnight aesthetic, along with a supersaturated color palette that throbs with purple, gold, indigo and every other Crayola shade you can imagine. I’m not sure what burnt sienna and raw sienna actually are, but I guarantee you they’re in here. The shadows in this movie have shadows; the grains of film shed and subdivide into dark snowflakes of black and crimson and green.

What’s the point of all this gorgeousness? That may pose a difficult question for some viewers. I guess it’s just meant to put you in the mood for love, as it were. Or at least in the mood to watch a couple of beautiful and lovelorn loners, Elizabeth (Jones) and Jeremy (Law), moon around in an empty New York diner, eating blueberry pie and pining for their lost whoevers. We’re not merely supposed to buy Law as a diner proprietor but also supposed to imagine that these two people have been unceremoniously dumped by their true loves, and that Elizabeth wanders off on a no-destination road trip after Jeremy has kissed her. (Pop quiz for female readers: Jude Law has just smooched the pie-à-la-mode stains off your upper lip. Is your very first reaction to buy a bus ticket for parts unknown?)

All that stuff bothered me at first, along with the fact that Jones can’t really act. When she’s required to display emotion about the former boyfriend, it’s more like watching somebody miss the bus or lose her cellphone than undergo a very early midlife crisis. Still, the camera loves her, as they say. (If there’s one thing Wong Kar-wai knows how to do better than any other filmmaker, it’s shoot beautiful women so they look their best.) She has a little of the young Julia Roberts, or a less extreme Angelina Jolie, about her. As the film progresses Wong seems to make more modest demands of her; on her road trip from one service-sector job to the next, Elizabeth is a likable wallflower, an observer of other people’s lives rather than the subject of her own.

Similarly, the chemistry between Law and Jones is nearly null at first — when Jeremy nuzzles in to give Elizabeth that sleepy smackeroo, I half-wondered if he was really after the dribbles of ice cream — but Wong and Khondji eventually create it out of images. There’s no nudity in “My Blueberry Nights,” and if anything it’s aggressively chaste. Except for a few cuss words it could probably be rated G. But the curves and swells and furrowed brows and twitching lashes of Law and Jones, captured in one lingering close-up after another, become their own kind of erotic landscape.

But because this is a movie about unfulfilled longing and delayed gratification, Elizabeth can’t just hang around Wong’s painterly New York night, watching the subway clatter overhead and inhaling pieces of blueberry pie with a really cute guy who happens to be single too. Jeremy’s diner doesn’t look like anyplace in the real New York, but I eventually quit worrying about that once I realized that no part of the movie happens in the real world. Wong’s America is the mythic, heartbroken America of Edward Hopper paintings and rhythm and blues records and Jim Thompson novels, and you can pretty much baste yourself in that flavor or move on.

In some ways, the nonromance between Elizabeth and Jeremy is the least substantial of the three roughly parallel segments of “My Blueberry Nights.” Once Elizabeth ends up in Memphis, where she becomes a waitress and bartender named Lizzie, who observes the not-so-gradual disintegration of a drunken cop (David Strathairn), the film’s prettiness and artifice finally yield some grit. Sitting in the moonlit shadows of Lizzie’s dive bar, Strathairn demonstrates why he’s among the finest of American character actors. With his bowed head, a few tired gestures and an almost masklike expression, he shows us a decent man drawing very near the end of a road paved with bad women (the worst of them played by Rachel Weisz) and bad liquor.

In the film’s Nevada section, Lizzie becomes Beth, a waitress at a backwater casino — I’m pretty sure it’s the Hotel Nevada, in Ely — who befriends a vivacious, tough-talkin’ Texas card shark named Leslie (broadly and enjoyably played by Natalie Portman, in a bad blond do and a succession of almost-trashy outfits). Wong and co-writer Lawrence Block (the well-known mystery novelist) flirt with cliché here, or maybe they embrace it whole-hog. After Leslie’s big showdown at the poker table (her weedy nemesis is Tim Roth, in an almost unrecognizable cameo), she and Beth hit the road in Leslie’s Jag for some lightweight “Thelma and Louise”-style adventures.

Neither that detour nor the film as a whole quite manages the emotional payoff it aims for, but by the end of this slight, charming, vaguely silly picture I was enchanted anyway. Art-house devotees of Wong’s work may have a tough time accepting the setting or the star (or the lightweight, sentimental tone) of “My Blueberry Nights.” And who knows whether Jones’ fans want to see her in a nearly plotless movie where she can’t make up her mind to snog with Jude Law. Still, this movie will seduce viewers one at a time with slow, lonely smooches and forkfuls of blueberry pie, even if it probably won’t be remembered as a major career event for its director and stars.

All in all, it wasn’t an uproariously successful opening for Cannes, but anybody left in a bad mood by “My Blueberry Nights” — not to mention the blue skies, blue sea and pink wine out in the French night — is just a sourpuss. Beginning Thursday, new films will roll onto the Riviera beaches like waves; among the most promising weekend premieres are Hou Hsiao-hsien’s “Flight of the Red Balloon” (inspired by the famous 1950s French short film), Michael Moore’s already-controversial “Sicko” and the Coen brothers’ violent western, “No Country for Old Men.” More soon.

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