AH, WILDERNESS! The perfect pictures of Ansel Adams are immediately recognizable, icons of the American West -- monolithic crags and ghostly valleys, sculpted riverbeds and striated canyons, still ponds and roiling clouds, trees festooned with snow and orchards embroidered with blossoms.

Such a prize-winning portfolio is open for perusal in the National Gallery in "Ansel Adams: Classic Images -- The Museum Set."

A few years before his death last year at age 82, Adams stopped taking orders for prints and concentrated on the "Museum Sets" -- six sets of 75 prints, with mini-sets of 25, selected by the photographer to represent his life's work. He printed them himself -- working his darkroom magic of dodging and burning in, and enhancing contrast to bring out the photos' drama.

Adams is at once as easy to read as a landscape and as inscrutable as his infamous Zone System, with its 11 tones ranging from blackest black to whitest white. That was the method he invented, a way toward perfection. An accomplished pianist before he took up the camera, Adams once said, "Your notes have to be accurate or else there's no use playing." Notes, tones, it's all the same. In the darkroom he sometimes used a metronome to time exposures.

But more than perfect technique, the Museum Set shows all the emotive power in the scenes that stirred Adams when he clicked the shutter. His photos are black- and-white because color was something he couldn't control, and color, he felt, didn't convey the feeling.

It was Adams' intention for the Museum Sets to have wide exposure; this set, owned by Pacific Telesis, is beginning a national tour here.

The mystical "Moonrise, Hernandez, New Mexico" is a popular inclusion in the collection: moon, clouds, hills, a little town and rows of crosses in a cemetery behind it, crosses that caught the glint of the setting sun. When he took it in 1941, Adams, supporting himself as a commercial photographer, was on a trip through New Mexico to shoot at the U.S. Potash Company, says Mary Alinder, his former assistant and the editor of his autobiography. And, as he often did, he took a day or so to photograph just for himself.

He was trying to photograph a recalcitrant tree stump. No matter what he did, it didn't work. Driving back to the motel room, he looked out the car window and saw what Alinder describes as "this wonderful light. He grabbed his tripod. He couldn't find his light meter. But only he would know, because he studied astronomy" says Alinder, "that the moon shines with 240 foot candles." He took one shot. The light faded. The crosses stopped glistening. So much for the insurance shot.

"Visualization" was another Ansel Adams concept that he figured out in 1927 while taking another famous picture. "Monolith, the Face of Half Dome" is a sheer rock face with a snowy base. Adams wanted to get the sky a certain majestic tone of black. He visualized the photo in his mind's eye and changed filters, knowing that a red filter would give him the desired effect.

Adams didn't limit himself to landscapes. He could take the exceptional portrait when so moved, as he did with the wistful "Mrs. Gunn on Porch," with a coathanger dropped on a daybed, the neighborhood bright outside, and the light just touching the old woman's cheek.

Though most of the scenes in the Museum Set are truly three-dimensional, he experimented with two. Eliminating the horizon and seeking out flat light, Adams made a line of surf into a series of abstractions.

He left nothing to chance, perhaps to the point of interference. For "Winter Sunrise, The Sierra Nevada, From Lone Pine, California," an assistant always had to spot-tone out the graffiti that spelled "LP" on the rocky hiside. And when his photos turned up as murals and screens, some found that excessive. But they worked.

Joining forces with the Sierra Club, and later, the Wilderness Society, Adams was an environmentalist who said he never took an environmentalist picture.

"He was ever vigilant," says Alinder. "We were in the Yosemite Valley, maybe the last trip we were there. Ansel called the head of the park because a telephone wire was strung right across one of the best views of Yosemite."

Soon, the wilderness was wild again.

ANSEL ADAMS: CLASSIC IMAGES -- At the National Gallery of Art through January 12, 1986.