Until 1976, when the Museum of Modern Art had its first show of work by southern photographer William Eggleston, color film was considered most unsavory in art circles.

For one thing, color prints faded. Worse, the medium had become the expensive terrain of amateurs who used it chiefly to bore their friends with home slide shows.

Most important, in the spare, tough formalist esthetic of the time, neither color nor anything else could be added to a photograph unless it was vital and inextricable from the whole: Merely adding color for the sake of prettiness was unforgivable.

Not always -- but often -- Eggleston had managed to make color vital: In a now-famous image of a red-ceilinged bedroom, for instance, the color became the subject; take it away and all was lost. That was to become the sine qua non for new color photography.

Eggleston also found a way to make color last by using expensive dye-transfer printing. With this, he created a package the Museum of Modern Art -- and its king-making curator of photography, John Szarkowski -- could believe in and promote. Since that landmark show -- the first solo color show ever at MOMA -- color has attracted other good photographers, and they have produced some of the most compelling new art in any medium.

But what of Eggleston? How does he stand up in the wake of the new color work he pioneered? Shows at Lunn Gallery and at the Corcoran bring us up to date and suggest that little has changed since the MOMA show. Nor has Eggleston bettered himself.

Spellbinding images still turn up, such as the moldy green tile shower from the "Troubled Waters" suite at the Corcoran and the bluest of blue glass bowls from the "Southern Suite" at Lunn. Also from the latter suite (published last year but photographed a decade ago) is a wonderful image of an airplane stripped of its engines and bathed in the warm pink aura of the last rays of sunlight coming over the horizon -- a time of day the artist favors.

There is much that used to seem tough and intimidating. It now seems repetitious and boring.

In the Lunn show, his more recent work, Eggleston continues to focus on the look of the South, where he was born and still lives. He still monumentalizes the incidental -- battered Wonder Bread signs, muddy bayous, overgrown cemeteries and an occasional human being -- always fraught with tension.

Also in this show, titled "5 Projects," are Type C prints from "Louisiana Project," still in process, the best of which depend less on color than on ambiguity. A field of green plants is photographed from a vantage point so low that all sense of scale is lost -- a device Eggleston has used before, but not for the purpose of bafflement as it is used here; in another intriguing and beautiful image, what seems to be an underwater scene turns out to be a steamy, smoking bog with the look of a fresh battlefield.

Curiously, Eggleston doesn't sell his photographic prints. Instead, you must order from the new images, and, eventually, the chosen ones will be issued in dye-transfer limited editions.

The "Troubled Waters" suite at the Corcoran, 15 dye-transfer prints published in 1980 and newly acquired by the museum, makes clear why Eggleston prefers that process. The quality of the color is incomparably vivid and gives a depth to each image that is sometimes lacking otherwise.

The Corcoran show continues through Oct. 24, the Lunn show through Nov. 6. The Corcoran is open Tuesdays through Sundays 10 to 4:30; Thursday evenings until 9. Hours at Lunn, 406 Seventh St. NW, are Tuesdays through Saturdays, 11 to 6. Alternatives to Galleries

Two Washington dealers who closed their galleries last season are finding alternative routes to the public eye. Jack Rasmussen has organized a show for the art gallery of Montgomery College, Rockville campus, with strong new works by 10 good painters he continues to represent: Bill Dutterer, Annie Gawlak, Tom Green, Walter Kravitz, Steven Kruvant, Dan Kuhne, Marianne La Roche, Nan Montgomery, Mindy Weisel and William Willis. This sampler of current painting in Washington is open to the public 9 to 4:30, Mondays through Fridays, Saturdays 11 to 2, through Oct. 28.

Photography dealers Gerd and Christine Sander -- who represent some of the great European photographers of the 20th century -- closed their gallery last year but continue an active private trade from their home in Silver Spring. Today, between 2 and 10, they'll surface again at the Holiday Inn, 8777 Georgia Ave., Silver Spring, with a sale of 3,000 vintage photographic prints from the archives of the Sickles Photo-Reporting Service.

Founded in New Jersey in 1938, Sickles was one of the early photographic agencies designed to serve advertising, business, agricultural and industrial clients -- rather than newspapers and magazines. The names of the photographers are not well-known, but all worked as professionals between 1938 and 1955, and their work is an interesting documentation of American life during the period. These are straightforward prints showing, among other things, the installation of the first parking meter in Seattle in 1938, dentists' offices, gas stations, Art Deco buildings, cars, refrigerators and other products photographed for advertising purposes. Prices range from $40 to $120.