Walter Hopps, the art scout - who thinks there may be 6,000 serious artists working in this city - will next month hang a show here open to them all.

Hopps has stretched behind him a record of art discoveries few curators can match. He gave Marcel Duchamp and Joseph Cornell their first museum retrospectives. He was one of the first to hang the works of Andy Warhol, Roy Lichtenstein, Barnett Newman, R. Crumb and Rockne Krebs in museum shows. His first "come one, come all" show will be held Dec. 7 at the Museum of Temporary Art (MOTA), 1206 G St. NW.

"36 Hours" is the exhibit's title. Though most curators work 9 to 5, Hopps, a known exception, will be on hand beginning at 9 p.m. for the next day and a half, installing works as they come in on a first come, first served basis until the 36 hours have expired or the gallery is stuffed.

"I'm not just interested in artists who are deservedly famous," said Hopps, the gallery's "right person." "Some people I've shown will never be; that doesn't make their art less interesting to me."

Hopps, former director of the Corcoran, the Washington Gallery of Modern Art, and the Pasadena Museum of Modern Art, now is adjunct curator of contemporary art at the National Collection of Fine Arts. Though he conceived this show more than 20 years ago, Hopps, now 46, says "the places where I've worked have been either unable, or unwilling, to put it on."

Hopps will hang the show "as thickly as possible, floor to ceiling, wall to wall."

Hopps yesterday observed that huge and open shows - the Armory show, the Panama Pacific Exhibition, the "Momentum" exhibitions held on Chicago's Navy Pier or the 1700-item. 400-artist show organized by Market in 1961 - are no longer much in favor. "Under Mayor Barry, the D.C. Arts Commission should find a space for such exhibits and keep it open the whole year," said Hopps.

Hopps said he'll accept "anything its maker wishes to call art, anything that's small enough to get in through the door. There will be no restrictions."

"Oh yes there will," said MOTA's director, Janet Schumckal. "We don't want photographs. We don't want big sculpture. We don't want paintings larger than four-feet-square." "You will notice," Hopps observed, "that institutions love restrictions.They even love them here."