CHROMA By Frederick Barthelme Simon and Schuster. 173 pp. $15.95

MINIMALISM, whether in the stories of Hemingway, the music of Webern, or the later plays of Beckett, has traditionally been defined as the concentration of intense thought or feeling into a tiny format. Recently, however, a new kind of minimalist writer has become addicted to taking something potentially large and interesting -- a separation, a death, a breakdown -- and flattening it into blandness; or, alternately, to taking something radically uninteresting -- a condo sale, a barbecue party, a trip to the mall -- and stretching it out through elliptical dialogue and sheer repetition, so that even the shortest shorts seem curiously long.

What all this flattening and stretching represents, we are told, is an honest commentary on the blandness and vapidity of our time. Our time may well deserve it. But does the reader?

As is illustrated in Chroma, a new collection of stories, Frederick Barthelme is one minimalist who knows how to have fun with the genre. His references to junk culture are irresistibly comic; his tone has a surreal, spaced-out serenity. In "Magic Castle," about a failed pick-up at the mall, the hero and heroine gaze at shoppers and listen to "the big happy music" coming out of speakers in the mall, "satisfied in some wholly immeasurable yet noticeable way." In "Architecture," a mutual friend asks an incestuous brother and sister on the run why they don't " 'go home and watch TV together like everybody else?' " In "Sis," emotion on a character's face is described solely in terms of someone watching a plane crash on CNN: "you'd watch the live coverage with this face," explains the narrator. Certainly no one can accuse Barthelme (as some critics have accused Mary Robison, Bette Pesetsky and others) of unconsciously aping television talk: For him, television is an insidious muse, an endless source of deadpan comedy.

Barthelme's shrewdest stories depict characters with a "mid life thing" attempting to capture a lost or never-attained hipster sensibility. In "Driver," a real charmer, a pool-accessory salesman sees a television program about San Diego lowriders and finds himself suddenly weeping because he doesn't have one. The next day he secretly trades in the family Toyota for a customized Lincoln, drives it to the mall where he impresses the girls, picks up two dogs at 4 a.m., and then tells the animals how weird he and his wife once were: " 'We aren't weird now,' I told them. 'But we were weird. Once. In olden days.' "

THIS IS THE cute version of the theme. Things get edgier when Barthelme's characters feel they missed out altogether, that they woke up one day and realized they were post-modern. The heroine of "Perfect Things" tells her husband she's having an affair with someone 20 years younger because she feels left out: " 'Of everything . . . The Vietnam War, for example. The Me generation. Farm Aid. The New German Cinema. The BMW crowd. I mean, where's my 505? Hawaiian shirts . . . The sexual revolution. Making ends meet -- remember that? . . . I hate the lawn, Jerry, know what I mean?"

For Jerry, the narrator, the main source of ennui is getting the newspaper every day "in this sick-looking robe I've had since Nixon." Yet Jerry knows that these exchanges are just "clever" ways of deflecting more terrifying issues like aging and loneliness. Unlike the trendy airheads in the collection's lesser pieces, he is a narrator with something to say.

The least attractive stories here are Barthelme's stylishly bleak present-tense tableaux, such as "Trick Scenery," where the anonymous second-person hero drives a steel gray '30s Chevrolet, observing at the conclusion how "endless" the highway is and how his "splash" of headlights "illuminates nothing." Look how cool I am, this story seems to say, how painterly and state-of-the-art.

When Barthelme tries too hard to be chic, even his wacky dialogue loses its edge. At the end of "Pupil," an 18-year-old student, after having barbecued chicken at her teacher's condo, reaches for a button on her Hawaiian shirt and says, " 'So now we start stuff, right?' " It's a terrific line, but it could have been uttered by any of the other characters, who are interchangeably hip and laconic.

At least this story has a conclusion, though. What's most grating about Chroma is that Barthelme, like his colleagues, often resorts to non-sequitur endings, a device as conventional and gimmicky as any O. Henry ending. At the end of the title story, about planned infidelity, the heroine looks as if she's about to say something significant, then asks her husband if he " 'could use some cheese ball . . . I am dying for cheese ball.' " At the end of "Sis," which is also about marital problems, the narrator responds to a difficult question by "trying to remember when we'd last had black beans, and it seemed to me that it had been a while." When we finish a story like this, we long to ask, as the characters surely would: Is that all? The whole deal? If you start stuff, shouldn't you finish? :: Jack Sullivan, who is working on a book of music criticism, writes frequently about contemporary fiction.