Celebrating 150 Years of Photography. A traveling exhibition of 400 groundbreaking photographs explores the vivid imprint of a medium that requires no brush or paint

`WE hope this is the thinking man's photography show,'' says J. Carter Brown, director of the National Gallery of Art. ``This is an enormously challenging show. We put away, right at the beginning, the idea of just doing `Photography's Greatest Hits,' just doing a mindless hit parade of the obvious familiar images.'' Mr. Brown is talking about a totally different approach, seen in an exhibition called ``On the Art of Fixing a Shadow: 150 Years of Photography,'' which brings more than 400 photos by 200 photographers to the National Gallery's West Building.

The names of the artists range from Louis-Jacques-Mand'e Daguerre to Andy Warhol. The title of the exhibit comes from one of the two fathers of photography, William Henry Fox Talbot, an Englishman who explained his discovery as ``the art of fixing a shadow.'' Talbot's invention, unveiled Jan. 31, 1839, in Cambridge, came just 24 days after Daguerre's announcement of a similar process in Paris on Jan. 7.

In the 150 years of photography that have followed, the pictures that require no brush or paint have left a vivid imprint on the world. Some of them are viewed as art.

Up until this year the National Gallery had held only two photography exhibits, one of work by Alfred Steiglitz (1978), the other of photos by Ansel Adams (1984). Both were retrospective shows of photographs donated to the gallery's permanent collection.

As Brown says, ``Photography used to occupy a kind of ghetto [in the art world], and that's what's been the revolution, I think. There were pioneers, like the Museum of Modern Art in the '30s, that had a photography department. In an art museum, that was considered very avant-garde....

``But now, more and more serious collecting institutions recognize that there is a body of art there,'' he continues. ``It's works of art on paper. It's a branch of the graphic arts, like printmaking, etching, or aquatint. And they have a responsibility to include that, too.''

The ``Shadow'' show, which has spent nearly three years in developing fluid, offers a scholarly look at the history of photography since its invention in 1839. Besides Talbot, Daguerre, and Warhol, the exhibition includes works by Eugene I think it's Eug`ene Atget, Edward Weston, Henri Cartier-Bresson, Walker Evans, Diane Arbus, Robert Frank, Dorothea Lange, Cindy Sherman, Ansel Adams, and Edward Steichen. In the opening room of the show, there are rare photos by Talbot, Albert Sands Southworth, and Josiah Johnson Hawes - works so light-sensitive that they're equipped with velvet veils, which the museumgoer must lift to see the photo.

For some viewers, the works that come closest to art are those most closely resembling paintings. In this show, Steichen's work floats in the memory like a great canvas: It includes his haunting forest reflected in water in ``The Pond, Moonrise,'' a platinum print toned with yellow and blue-green pigment; his dramatic black-and-white self-portrait with brush and palette; the soft, peacock twilight of ``Flatiron,'' in which that stark, angular building is captured in a blue pigment gum-bichromate/ platinum print.

AMONG the other memorable works are: Julia Margaret Cameron's 1867 carbon print of a yearning woman, which might have been a pre-Raphaelite painting; next frag. phrase is confusing its title, ``Call, I Follow, I Follow, Let Me Die!''; Edward Weston's almost abstract cloud and mountain study, ``Mount Lassen National Park,'' a gelatin silver print; Alfred Steiglitz's ``Georgia O'Keeffe,'' a study of his artist-wife's hands that rivals anything by D"urer; George Seeley's evocative untitled winter landscape from the turn of the century, which is pure photo Impressionism; and David Hockney's contemporary ``Pearblossom Highway,'' which up close is clearly a photo collage of dozens of color photos but at a distance might be one of his California paintings.

Other fascinating photos by painters are included in this exhibit, among them Edgar Degas, Pierre Bonnard, Thomas Eakins, 'Edouard Vuillard, and Thomas Sheeler.

But there are also memorable photos that have no resemblance at all to paintings: Jacob Riis's 1890 photo ``In a Sweatshop,'' a Dickensian study of a 12-year-old boy at work pulling threads in a factory; Robert Capa's not by chance Capra? ``Naples 1943,'' a war picture of women weeping over their dead; Dorothea Lange's ``Migrant Mother, Nipoma, California, 1936,'' the mother ragged, unkempt, indomitable as her children bury their faces in her shoulders.

There are arresting portraits: Henri Cartier Bresson's it's Cartier-Bresson, as in 1st mention, no[ photograph of Jean-Paul Sartre, looking skeptical on a bridge; Steichen's study of a bearded Rodin, ``Rodin - the Thinker,'' with the sculptor facing his famous statue; and 'Etienne Carjat's brooding study of Baudelaire.

Then there are a few photos that make you wonder why they're here, ones like Edward Weston's 1925 study of a washstand that might have graced the pages of a plumbing catalog.

THE eye yearns for color at times, particularly in the early rooms of this chronological exhibition, where the historic photos are studies in tan, brown, and gray.

The show is divided into four sections: ``The Pencil of Nature (1839-1879),'' ``The Curious Contagion of the Camera (1880-1918),'' ``Ephemeral Truths (1919-1945),'' and ``Beyond the Photographic Frame (1946-Present).'' It was organized jointly by the National Gallery of Art and the Art Institute of Chicago and co-curators Sarah Greenough and David Travis.

As many other museums kick off 150-year salutes to photography, questions arise about whether that medium is competing with, or usurping the place of, paintings in museums and galleries pressed for funds.

Speaking for the National Gallery, Brown says, ``Our major responsibility is still to the other media. But I have noticed that ... university museums and smaller museums have diverted resources to [collecting] photography, largely because the prices of everything else have gone absolutely astronomical....

``One can still buy beautiful images for a lot less money in that medium. ... This year there has been a flurry because [of] the anniversary. But I think, over the long run, it's not going to supplant [painting].''

``On the Art of Fixing a Shadow,'' which closes here July 30, will be seen at the Art Institute of Chicago from Sept. 16 to Nov. 26 and the Los Angeles County Museum of Art from Dec. 21 to Feb. 25, 1990.