Much welded steel sculpture evokes a sense of muscle, of art achieved through strain. A child can shape clay. But steel is intractable, steel defeats flesh. Its spirit is nonpastoral. Stone suggests the earth, wood suggests the tree, but steel calls to mind the anvil and the hammer's fall, fire and the forge, the blinding light of welders' arcs, grimaces and sweat. Perhaps it is no wonder that much art made of steel feels unsmiling, even anguished.

Washington's Christopher Gardner makes hard steel objects of a different sort. His sculptures are on view now both at the Middendorf Gallery (2009 Columbia Rd. NW) and, outside, at the Phillips Collection (1500 21st St. NW). He has somehow overcome his material's heavy-heartedness. His art is always jaunty, its spirit always light.

His sculptures, even those that weigh a ton, have a playful twinkle. Their planes and perforations, their highlights and shadows, and the twinned and contradictory colors he prefers -- a shiny Chinese red against a matte blackboard-black -- joke with each other like a pair of comics gabbing on a stage.

The first piece one encounters at Middendorf is called "Running Around in Circles," and it seems to do just that. This work, like others shown, began its existence as a disk of half-inch steel plate, seven feet in diameter. Arcs and curving arrows and other active shapes, cut out of the steel, dive through the resulting holes like so many dolphins. They zoom by one another, first this way then that, and those that touch the ground hold the heavy metal disk upright in the air.

Gardner likes to load his art with untendentious references -- to waves and waving seaweed ("Undersea Adventure"), to the grinning, toothy faces cut in Halloween pumpkins ("Breaking the Mold") or to clumped-together magnets ("Magnetic Forces"). One piece, called "Off the Record," has the center hole and sharply pointed needle -- and implies the music -- of a disc jockey's disc.

Much steel art just sits there, encased in its heaviness, but Gardner's work, in contrast, is full of dancing movement. Its ideas chase the mind around, its arrows change directions, its colors shift from red to black and back to red again, and his sculptures, seen in sunlight, cast sharp and complicated shadows. Yet Gardner avoids chaos. His art is rightly balanced. All its movement, all its dash, is somehow held in check. Its wit is anchored by its hard-and-heavy steeliness, and its joyousness is countered by the formal rightness of its shapes. Middendorf has given him a strong, good-looking show. It closes June 4. Photographs by Lotte Jacobi

Einstein, Thomas Mann, Bruno Walter, Marc Chagall, Allen Dulles, Peter Lorre, Lotte Lenya, Robert Frost -- the fine and famous faces in Lotte Jacobi's photographs at the Martin Gallery (3243 P St. NW) poignantly evoke more than 50 years of history, America's and Germany's. And yet these portraits have not dated. Since the 1920s Jacobi, 89, has been making artless art.

Karsh of Ottowa's formal portraits all look pretty much alike, those of Avedon as well resemble one another, but a sort of stylelessness is Jacobi's only style. She photographed Robert Frost in 1959 -- he sprawls there in his chair, his shirt is white as snow, his aging face is shadowed, his image calls to mind New England as succinctly as a white enameled doorknob on a weathered wooden door. The face of Kathe Kollwitz (1931) is as sorrowful, as strong, as the pictures and statues that brought her fame. That of Marc Chagall is as joy-filled as his paintings. He stands before his easel, his paintbrush in his right hand, his palette in his left, smiling at the camera while his laughing daughter leans her head toward his. Lotte Lenya with her bee-stung lips (circa 1928) holds her flattened cigarette just below the ember as if unafraid of flame.

These portraits are not posed. A few of them (for instance, an image of Eleanor Roosevelt from 1944) seem little more than snapshots, but a clear sense of communion between Jacobi and her sitters gives most of them strength.

Her history connects her to the first years of photography. In 1840 her great-grandfather went to Paris to consult with Daguerre. Her grandfather ran a photographic studio in Berlin, so did her father, so, eventually, did Jacobi. It was more than just a studio, it was a gathering place for Germany's scientists and artists. Einstein, Emil Jannings, Laszlo Moholy-Nagy and Max Planck were among those who dropped in. "There were always people coming in and always something going on," she says.

Jacobi, who had tried her hand at filmmaking and acting, had much affection for the theater of Berlin. One of her theatrical pictures here -- of jackbooted soldiers gathered around a table on which sits a human skull -- seems an image from George Grosz.

Like him, she fled Germany after Hitler became chancellor. In 1938, when Life magazine asked Albert Einstein if he'd permit a portrait, he insisted that the picture be taken by Jacobi. His white hair is uncombed. He is wearing a black leather jacket with, so it appears, no shirt underneath. (He disliked socks as well. "They only get holes in them and need mending," he explained.) With a fountain pen in hand and a notebook on his lap, he is writing chains of formulas. He seems entirely at ease in the presence of Jacobi. So do all her sitters. She does not strike the viewer as much of an artist (as does, say, Ludwig Sander, who also portrayed Germans), but one never for a moment questions her integrity. Her exhibit closes June 29.