Blue-light specials: `one hour photo' & `the good girl'. (Screen).

Robin Williams has a Jekyll and Hyde kind of career. Williams's triumphant roles have been the ones tailored to fit his shtick--the jumped-up, troublemaking DJ of Good Morning Vietnam, or the madcap, gender-bending Mrs. Doubtfire. These characters let him score points the same way he did in Manhattan comedy clubs and as the antic alien in Mork and Mindy. Mork was television like you've never seen before, a showcase for Williams's patented brand of riffing, hyper, freewheeling babble. His genius, then and now, is for brilliance under pressure, an inner pressure of manic improvisation.

Williams's recent HBO special showed he still can crank it up; but onscreen over the years he has seemed bent on repenting of his comic excesses. The sorrowful-soulful immigrant in Moscow on Hudson; the compassionate shrink in Good Will Hunting; the tragicomic Jakob Heym in Jakob the Liar, consoling his neighbors in the Polish ghetto with fabricated reports of Allied triumph from an imaginary radio. Sure, here and there Williams let a brilliant improv slip through (impersonating Winston Churchill in Jakob the Liar, for instance, or Marlon Brando doing Shakespeare in Dead Poets Society), but mostly these roles seemed designed to convince us he can play big emotions. Too often, the result has been a strained poignancy, with Williams assuming a weepy, smiling, misty-eyed expression that obliterated the madcap and gave us the maudlin instead.

Recently, Williams seems to have decided this tack wasn't working. So he checked himself in for what critic J. Hoberman has wittily called "a complete Clockwork Orange makeover," effecting a transformation from funny man to soul mate to psycho. As Walter Finch, the killer in this summer's Insomnia, he exuded the low-key creepiness of a petulant psychopath. Now, in Mark Romanek's One Hour Photo, he plays department store photo clerk Sy Parrish, a pathetic loner avidly peeping into the lives of his customers as revealed in their family pictures. Over time his fixation has settled on one family, the Yorkins; pretty Mrs. Yorkin (Connie Nielsen) makes Sy fidget with nervousness, and ten-year-old Jakob (Dylan Smith) propels him into fantasies of avuncular bliss.

There's nothing sexual about these yearnings, at least not as Romanek writes them; Sy pines to belong, to play the benevolent and beloved uncle. When a waitress in a diner sees him smiling over snapshots of the Yorkins--he's made copies for himself--and asks if they're his relatives, we note the little thrill he gets from claiming them as his own. Later, as he watches junk TV at his dreary apartment, we see that the wall behind him is a huge mural comprised of hundreds of images of the Yorkins, photos he's been stealing for years. It's authentically creepy.

Romanek has a firm grip on one irony, the gap between how Sy understands himself--the would-be uncle--and how we see him: obsessed, wounded, and capable of harm. In another unsettling scene, Sy shows up at Jake's soccer practice and clumsily tries to pal around. Anything can happen, you sense--and when the overture ends in an innocent gesture, you sigh in relief. "I've watched him grow since he was this big," Sy says to Nina Yorkin about her son--fondly, as if he'd been there. He can't see his voyeurism for what it is; he imagines he loves the Yorkins. Yet theirs is not the perfect family he has fantasized about; and when cracks appear in the surface of the Yorkins' happiness, Sy flips out, his latent resentments bubbling up, threatening an explosion of violence.

The scenario closely resembles Joseph Ruben's 1987 The Stepfather, in which a handsome drifter searches out young widowed and divorced mothers, presenting himself as a mild-mannered family man, and marries them, trying to create the happy family he has always obsessed about. Then, when things start to go bad, he psychotically murders them. The Stepfather gave this fervid material an edge of black humor, and aimed a passing jab at Reagan-era family pieties; but Romanek takes the setup oh so seriously, and there's a gleam of the meretricious in how his movie dresses up alienation in cool pictures. One Hour Photo is an art-house suspense film, a careful miniature that makes its points through studied visual constructions, like the relentless chromatic contrasts that define the colorlessness of Sy's life--his clothes white and gray, his car white, the furniture and paneling in his apartment a dreary shade of oatmeal--versus the Yorkins' rainbow tumult of toys, gardens, blue pool. Romanek made his name producing music videos (for Madonna, among others), and he's not reluctant to stylize in order to further his compositional motifs. When, for instance, was the last time you saw a police interrogation room empty of all furniture, gleaming laboratory white? One Hour Photo isn't about character, really. It's about the lighting and the color and the sharp edges of things; it's all about the pictures. You can decide whether the film is bolstered or punctured by this ultimate irony.

Still, the movie has something going for it; you complain and complain, but leave the theater realizing that it got to you anyway. Williams's performance helps, with its mix of trembly nervousness, Uriah Heepish abjection, and latent rage. check your smile, a bathroom sign admonishes SavMart employees; Williams all but eliminates his, tamping down his expression until he looks like a man at a funeral. As a comic, Williams is all about speed; it's enjoyable to watch him play against type, putting the brakes on his manic engines, steering low and slow through this dark little film.

The Good Girl is another movie from Fox Searchlight, which seems to have cornered the market on superstore angst. But unlike One Hour Photo's upscale SavMart, the Retail Rodeo lies deep in shabby blue-collar Texas, and defines a world so boring the security guard amuses himself by toe-tapping the automatic door open and closed for hours on end. Jennifer Aniston plays Justine, a thirty-year-old cashier who lies awake at night in a lather of misery. Bored to tears by her husband, a big lazy lunk of a pothead (played by the always-terrific John C. Reilly), she lets herself fall for a co-worker (Jake Gyllenhaal), a callow twenty-one year-old who calls himself Holden--guess why?--and whose morosely handsome face and writer affectations convince her he's just what she needs.

The director, Miguel Arteta, created Chuck and Buck, and again he's on the trail of mismatched love. This film's nice turn is to set up romance and then strip it down piece by piece to mere romanticization, as Justine comes to see that beneath his show of alienated intensity, Holden's just a whiny, horny boy who offers her no future. (It's also a witty reminder that if the "real" Holden walked out of the book and into your life, he might be an insufferable drag as well.)

The Good Girl has its problems, but there's nice acting all around, especially by Aniston, one of the stars of TV's Friends. TV comedy works not by depth of character but by the opposite, by cuteness, quickness, and above all predictability--the iron rule that no character should ever be caught in an expression or utterance the audience doesn't recognize instantly. Moving from that to a movie can spell disaster for an actor, but Aniston pulls it off with ease. She's got a passable soft Texas drawl, but more important, she knows how to convey what's not being said. One inward, doubting look, and she has created more presence than in a hundred episodes of Friends, and reminded us once again why sitcom's jokes amuse, but cinema's joys endure.