WHEN HE began producing his strange "Still Life ConW structions," now at Kathleen Ewing's 3243 P St. NW, Frank DiPerna took a chance.

He left the realm of straight photography where he'd made his reputation, and dared his public to accept him as a kind of painter-sculptor. Instead of hunting for his subjects out there in the world, he began composing them on his studio wall. He took a chance -- and failed.

His experimental photographs breathe exasperation. Beneath their groping, and their goofing, one feels a deep frustration. It is as if the artist, offended by his medium's built-in limitations, and angered by the prospect of doing yet again what he'd done so well before, decided, ah, the hell with it. He'd try something wholly new.

What he did was this: He arranged assorted objects -- black balloons and cheese graters, bits of colored tape and tubing, feather dusters, paint rollers and nudes -- against his studio wall. Then he photographed them there.

It is not easy to discern whether these constructions had merit to begin with. Photographs of works of art rarely do their subjects justice. The colors never seem quite right. The scale is uncertain. Reproductions lie.

Yet that is all we get here -- color reproductions of absent works of art.

DiPerna the photographer, not the painter, not the sculptor, is an admirable artist. His work is finely printed. His images have rigor. Whether he is working in black-and-white or color, all his compositions seem thoughtfully considered. His colors are, or used to be, finely tuned and quiet, free of the beginner's (or the National Geographic's) usual reliance on unnecessary accents of bright yellow, red or blue. DiPerna knows just how to balance the organic and the classical, the soft and the severe.

A number of these virtues may be glimpsed, if dimly, in his "Still Life Constructions." He still retains his fondness for slightly broken symmetry and subtly tuned color, though too often in these photographs the symmetry seems harsh and the subtlety diminished by the garish plastic colors of his garish plastic props. In the straighter, larger pictures upstairs -- of parks and pools and flaking walls -- DiPerna the photographer is seen to good advantage. But in the constructions, his stabs at wit seem forced. Their iconography, when figured out (crossed fly swatters, a hula hoop), doesn't make much sense. They are neither fish nor fowl. They will be on view through Nov. 18. Shirley True at Catholic U.

Washington's Shirley True is another straight photographer distracted by the arty. She finds images that echo. She's fast. She responds with assurance to transitory subtleties of texture and gray light. Her photographs seem heartfelt, as if made with love. Some 20 are on view now in the art department gallery at Catholic University. They diminish one another.

Despite their varied subjects -- a front porch seen in sunlight, a child in a wet suit, a snoozing cat, a truck--her exhibition drones.

True, for reasons never clear, insists on making pictures with a cheap Diana, a kind of toy camera whose images are never more than partially in focus. And when she prints her pictures, she does so without cropping, including on the paper everything contained in the negative-carrier, not just the primary image, but to its right or left or both, adjacent little strips of the photographs she made just before or after.

True, who also writes and draws and paints, has written that she regards photography as her "primary medium" for this reason: "It is the only medium that deals directly with the actual -- with the objective, physical, material world . . ." Good enough. But the actual in this show never gets a chance. It is pounded into blandness by her equipment and technique. The blur that works in one picture, "Square Bush," for example, damages another, that Gossage-like front porch. Her stripes get in the way. Her repetitious tricks undercut the freshness that's the soul of her potentially good art. Her show closes Nov. 5. William Newman at Gallery K

A memory of photographs -- found, snipped out and pasted down--hurts the finely made drawings of Washington's William Newman, now at Gallery K, 2032 P St. NW. The feel of casual collage infects the beauty of his handiwork, his graceful arabesques, his quiet tones of gray. It took months to make these pictures, yet they feel like easy art.

One can almost hear his horses snort, and feel their sweaty hides, and smell the roses and the apples that float above their heads. Still these pictures seem unreal. Their disconnected parts -- their goldfish, nudes and lounge-lizards, their quotes from Rubens and Rodin -- are very strong. It is the whole that's weak. These drawings smell of paste.

Their elements don't cooperate. Each carries its own light source and floats alone in an empty sea of uninflected white. Newman's horses seem celestial. His females are lovely. He can turn a little boy bouncing on a bed into a Francis Bacon monster. Newman never merely copies the photographs he works from. But he leans on them too hard. His show closes Saturday.