The big, inclusive survey of Washington photography that goes on view today at the Washington Project for the Arts is a small revelation. Its subject is the '70s and, surprisingly, it shows us that throughout that old decade, while the painters of this city were moving every which way the photographers of Washington were instead coalescing.

Influenced by many things -- a growing disapproval of minimalism's rigors, the example of Mark Power, the shows they saw around them, feminism's victories, the snapshot, the toy Diana camera -- they gradually developed a shared attitude, a look.

That there is a special softness to Washington's photography was not before apparent, but a peculiar sort of gentleness, something sweet and intimate, dominates this show.

It is called "A Different Light." It was organized by Shirley True, who with 410 prints borrowed from her colleagues has mounted not just one big show, but 35 little retrospectives. A few well-known names are missing, John Gossage's for example, but the True show on the whole is as accurate an overview of Washington photography as we have yet seen.

No single subject dominates. There are pictures here of southern barns and skid row bums, of nudes and dogs and flowers, cabbages, stuffed deer. Nor does True's exhibition attempt to spotlight stars. What unifies her show is, instead, a mood.

In December 1970, when Walter Hopps first showed Cameron and Szabo, Gossage, True and Power at the Corcoran's Dupont Center, much art made in this city still seemed strict and grandiose. Painters then were working here with canvases as big as walls, masking tape and rulers. The photographs of those days were comparably rigorous. In them one would often see grids, parallels, right angles; their human figures sent out Diane Arbus shocks.

Although photographs of both sorts -- Geometricals and Grabbers -- are included in this show, they are much outnumbered by images that do not shout, that instead sing and whisper. The look of light on growing things, a wisp of hair upon a neck, the gesture of a woman's hand, are among the quiet images one remembers.

Through the camera is a machine that records the things it's pointed at, the best artists represented here look not out, but in.

The poignant, perhaps feminist photographs of True, Joyce Tenneson, Rosemary Wright and, to a lesser degree, Nancy Rexroth, are frankly autobiographical. In Power's pictures of his friends, in Allen Appel's of his wife, in Szabo's deeply moving Eastern Shore landscapes and even in Bill Christenberry's fine, straightforward views of the decaying South, one feels the artist searching, aiming not at things but rather at affections, memories and dreams.

Of the artists represented, a number of the best -- Power, Szabo, Rexroth, Cameron, Appel, Frank Herrera and Mike Mitchell -- have often shown before. The pictures they display reinforce their reputations. But there are 400 photos here and one cannot help but notice the especially sweet images that leap out of the mass.

Among the memorable pictures here are Tom Shuler's "Tall Grass," Herrera's "Beverly," Cameron's grass studies, Power's early roadscapes, Wright's cup-up self-portraits, Maxwell Mackenzie's pebbled beach, Frank DiPerna's "Mark Power Portraying Lewis Hine," the stuffed deer of Robert Epstein, Lynn Allen's "Susie's Shoulder," and her shipboard nude.

This show is not all beautiful; for every photograph that strikes, two or three are easily forgotten. But "A Differen Light" succeeds in conjuring the past decade, its drift away from fashion, its curators and currents. The show continues at 1227 G Street NW through Jan. 31.