Helen Frankenthaler, the much admired and promoted "second generation Abstract Expressionist," tells everyone who asks her that she paints by intuition.

So it is not surprising that her abstract art suggests something vague and daydreamy, a shunning of systemics, a quality of drift. She begins a picture by putting down what seems to be an arbitrary mark -- a calligraphic brushstroke, a line, a blob of color -- then decides if she likes it, then puts down another. If she has a method, it is wholly unmethodical. There is no way the viewer can figure out her art.

"Helen Frankenthaler Prints: 1961-1979" opens tonight at the Phillips Collection here. It is a surprising show.

It calls into question her self-proclaimed reliance on whim. For the making of a colored print is a slow and tedious business. You cannot intuit the printing, say, of a lithograph from five stones, or a silkscreen from four screens, or a sugar-lift, aquatint and drypoint from three copper plates. Yet these are seen throughout Frankenthaler's show.

Some of them are lovely; more of them are tepid. Frankenthaler's art is notoriously uneven. A painter fond of automatism and unafraid of accident can take great risks in pouring colored paint on canvas. But that sense of risk, of tingling danger, is inevitably diminished by the methodical production of a complex colored print.

Frankenthaler says, "I am not interested in the techniques of printmaking. I am not interested in the patience it requires. I am not interested in the chemistry. I want it done for me." One does not quite believe her.

For throughout this exhibition we see her work with various woods, with oak, birch and mahagony, with copper plates and plywood, with various inks. In "Essence Mulberry," she uses mulberry juice and seeds. We read the little note she sends her printers: "No schmaltz, pliz!" she writes. What is an orange stripe in a woodcut named the "Savage Breeze" becomes a stripe of green in another titled "Vineyard Storm," made from the same blocks. The major difference between "Variation I on Mauve Corner" and "Variation II," is that the image has been turned 90 degrees. Her exhibit is, above all else, a patient exploration of the printmaker's techniques.

There is an eerie contradiction at the center of her show. Something of the sort was sensed when the prints of Edvard Munch were shown in 1978 at the National Gallery of Art. Munch, the painter of "The Scream," seemed an artist tortured, as focused on his anguish as Frankenthaler is on her floating intuition. One might think that both of them would utterly reject the time-consuming tedium that is involved in printmaking, and yet they seem to love it. Frankenthaler's images look spontaneous; Munch's look as if they were torn out of his misery. Yet both of them spent happy years fine-tuning their fine prints.

One leaves this show with renewed admiration for Frankenthaler's colors. Look for instance, at the proof of "Essence Mulberry" to which she has added subtle tones of pink. It is her images that irritate -- those wandering scraggly lines, those moist colored blotches. We have been taught to forgive much Abstract Expressionist messiness -- See the noble battle! See the artist-hero struggle as she paints!

But Frankenthaler's prints were produced, expensively and slowly, by teams of master printers. Even at their loveliest, when their colors save them, they do not seem heroic -- but decorative, highly fashionable, tame.

Frankenthaler makes what is, in 1980, overly promoted academic art. She has been from her 20s a member in good standing of abstract art's establishment. She met the critic Clement Greenberg, who was 21 years her senior, when she was still at Bennington, and "through Clem I met everybody, the whole cast." She met Franz Kline, David Smith, Morris Louis, Kenneth Noland, Gorky, Jackson Pollock. And she married Robert Motherwell. One leaves this show suspecting that her reputation rests as much on the fame of her connections as it does upon the beauty of her art.

Her exhibition catalogue, published in connection with the Williams College Artist-in-Residence Program, is a book of homage. Photographs of the artist's face appear in that volume more than 20 times.

She has a gift for delicately balancing startling, looming shapes. And her colors sometimes sing. But despite the care taekn by the teams of printers who produced these lithographs and etchings, these woodcuts and these silkscreens -- a care that tends to lend them a kind of awkward weight -- this show is somehow slight. Like a good interior decorator, Frankenthaler has an arsenal of tricks -- see the way that scraggly line almost, but not quite, strokes that heavy shape; see the way she works with that picture's edge. One most admires Frankenthaler not for her daring, but for her attention to detail, her color sense, and for her good taste. Her exhibit at the Phillips closes Oct. 19.