TO SEE "Gemini G.E.L.: Art and Collaboration" at the National Gallery, first you have to get past the 18-foot orange inflatable bladder, "Ice Bag," that undulates on the ground floor of the East Building. By Claes Oldenburg, it would overchill the worst hangover. Beyond it are more than a hundred works by 30 other contemporary artists and their collaborators.

When it first opened in 1966 in Los Angeles, Gemini G.E.L. (Graphics Editions Limited) was just a lithography workshop for the stars, such as artists Jasper Johns, Roy Lichtenstein, Robert Rauschenberg and Frank Stella. But with an open-minded philosophy, it has since collaborated on everything from polyurethane car profiles to televisions made from gas cans -- in numbered editions. After all, if you're going to the trouble of making a "Double Nose/Purse/Punching Bag/Ashtray," as Oldenburg did in 1968, why not make 75?

Collaboration is as handy as frost-free refrigerators. Gemini printmakers do the printing for the artist. Or maybe the artist wants to work in metal without becoming a welder. For "Cloud Mountain," Isamu Noguchi started with a drawing, then, using a light material called "Fome Core," cut out a full-scale model; it was up to Gemini to have the sculpture made in galvanized steel.

This is not to overlook the exciting lithographs in the show: portraits by David Hockney; Johns' and Stella's mesmerizing graphics; Lichtenstein's "Head" from his "Expressionist Woodcuts," and one of his first prints at Gemini, a homage to Claude Monet's cathedral series.

Rauschenberg's first print at Gemini, "Booster," in 1967, boosted the size of hand- made contemporary prints. Six feet tall, this self-portrait shows the inner man of the artist, literally, with a full series of head-to-toe X-rays. Rauschenberg's other works in the show range from "Cardbird door" (apparently boxes opened out and glued together, but in fact the labels, dirt and tape were copied from boxes and printed on) to "Capitol," a fragrant construction of Indian "rag mud" containing fenugreek powder and ground tamarind seeds.

Rauschenberg is Gemini's biggest booster: "I don't trust the independent ego no matter how much talent is surrounding it," he says. "I like that exposure to working with the unknown you have in a collaboration." And if he has an idea when he arrives at the Gemini studio, he says, "That's the first one I throw out."

GEMINI G.E.L.: ART AND COLLABORATION -- At the National Gallery of Art through February 24.