NEW YORK - Now that it has opened, it is easy to see why the initial unveiling of "Impressionism" was postponed. Despite a solid cast headed by Jeremy Irons, Joan Allen and Marsha Mason, this new American play by Michael Jacobs too often feels like an art history quiz.

Slides of famous and less-well-known paintings flash up in the projection design by Elaine J. McCarthy in the scattered and inconclusive production that opened Tuesday night at the Schoenfeld Theatre. Though it runs an intermission-less 90 minutes, the eight-scene opus directed by Jack O'Brien seems much longer as it slips back in time and jumps about the globe.

Allen excels as a gallery owner, Katharine Keenan, who initially appears to be reluctant to sell her works. Irons brings his usual British coolness to her assistant, photographer Thomas Buckle. Mason beams like a cat with a saucer of cream as Julia Davidson, a rich arts patron.

When the play begins, four artworks adorn the functional setting by Scott Pask, with its two desks. At left is "La Toilette" by Mary Cassatt, with a mother bathing a small child. Next to it is "Seated Nude," an especially alluring canvas by Amadeo Modigliani. Then comes a photograph of an African boy and some dark, spiky branches, "Joseph in the Mutondo Tree." But that gives way to a Marc Chagall lithograph of a mermaid holding a bouquet of flowers and jumping out of the sea, "Bay of Angels." At right is "Tomorrow She Finds Him Slumped Over" by a fictional Palmer Wilson, depicting an elderly couple on a bench.

Upon entering with a box of pastries, Katharine immediate replaces the Chagall with the photograph. She tells Thomas an amusing and suspenseful story of being bowled over on the subway by "the most enormous man God ever made." Later in the scene, Thomas tells of photographing a mangrove estuary for National Geographic.

This raises the question of why he should be working as an assistant to Katharine when he has received such prestigious assignments. Finally, at the end of the play, we at last learn the reason.

After Thomas explains what a mangrove estuary is, Mason's Julia, opulently costumed by Catherine Zuber, makes a grand entrance.

She tells Katharine that she will never sell the Cassatt aquatint "because you're overpriced." She further announces that she is about to "become a grandmother by caesarean section."

Despite the price, she decides she wants "La Toilette."

The scene ends, and projections of mothers and daughters fill the downstage scrim that originally held blow-ups of the paintings in the gallery.

Scene Two is brief and takes place in Katharine's memory. Her mother, Rachel, played by Allen, is washing the 6-year-old's feet in a basin and lecturing her about dirty feet. Irons turns up as her father, Henry. He and Rachel argue about their future together.

Slides of paintings by Renoir, Chagall, Picasso and Klimt lead into Scene Four, in which Katharine, then 30, is posing for Palmer Wilson in his SoHo loft. Irons plays the painter. She declines to remove her sheet. After some banter, Nicole Halladay, an NYU senior played by the radiant and sassy Margarita Levieva, arrives and comments, "He lets you keep the sheet on?" Sandra, played by Mason, also arrives at this busy atelier.

In the final scene, the play ends on a hopeful note. At last, it projects feeling.

IMPRESSIONISM runs through July 5 at the Gerald Schoenfeld Theatre, 236 W. 45th St., New York. Tickets are $66.50 to $116.50. Information: 212-239-6200.