National Gallery director J. Carter Brown talked of sex and Rodin's work last night, as more than 100 guests savored smoked salmon and escargot canape's in the East Building concourse.

The occasion was a short, modestly elegant reception prior to the premier of "Rodin: The Gates of Hell," a new 53-minute film documenting the casting of the 20-foot-high bronze "Gates," which form the centerpiece of "Rodin Rediscovered," the gallery's current blockbuster retrospective of work by French sculptor Auguste Rodin (1840-1917).

It could have been a fond farewell: The show was due to close Sunday, with a million viewers under its belt since its opening in June. Instead, Brown used the occasion last night to announce that it has been extended through Easter. "That's good news for all the procrastinators and the waves of tourists who come to Washington in the spring," beamed Brown.

"Only the drawings will have to go," he said, explaining that their departure had to do with the danger of overexposure to light, not the salacious nature of some of the subject matter. "Too bad, but the sculptures are pretty sexy, too," assured Brown, who was still chuckling over one artist's complaint that the show had evaded the issue of Rodin's eroticism. "Everyone who sees this show thinks it's drenched with sex in every section -- I'm surprised there weren't more complaints. But I only made one deletion: I changed the label on a drawing titled 'Woman Masturbating' to 'Nude.' After all, this is a family institution."

Standing to receive an enthusiastic ovation after the preview was the star of the evening, Iris Cantor, who was creative consultant and co-producer with David Saxon of the film, which was bankrolled by her husband, B. Gerald Cantor. The largest private collector of Rodin in the world, and the owner of his own skytop Rodin museum at Manhattan's World Trade Center, Cantor also commissioned the giant casting of the "Gates of Hell" featured in both the film and the exhibition. He won't say how much the casting cost, "but it is insured for $5 million," he said.

"But the film only cost a half-million, give or take a few thousand," noted his wife, who came up with the idea of documenting the monumental and complex three-year casting job at the Coubertin Foundry near Paris. Paul Boorstin, who wrote the script, was at home in Beverly Hills but was represented at the party by a pair of proud parents, Ruth and Daniel, librarian of Congress, who said he'd "like to be a writer too when I grow up."

Other conversations centered on art: The wife of newly arrived Greek Ambassador Nicolas Karandreas bemoaned the fate of the Parthenon's sculpture in Athens' polluted air. A clutch of art historians mumbled that the film had gone overboard in its claim that Rodin was the only Michelangelo-inspired sculptor in 300 years who had "a talent to rival the master himself." "That comes as news to fans of Bernini," complained one, sotto voce. "But I think the film is very educational," insisted a tuxedoed Richard Helms, former CIA head, who had to leave early for a Georgetown dinner party. "Everyone knows Rodin made 'Le Penseur,' but I for one didn't even know he made any Gates."

For the benefit of others who also have something more to learn about Rodin, the film will be shown daily in the gallery's East Building auditorium at least until the show closes April 11 -- and possibly longer. "We're still not sure where the 'Gates' will go next," said Cantor, though he did say that they will make several stops as they wend their cumbersome way west to Stanford University where they will ultimately become part of the B.G. Cantor Sculpture Gallery. "The Met in New York is consulting with their engineers to see whether the Gates can be shown there next, and Boston is also interested."

"It's complicated," concluded Cantor. "These things weigh 8 tons, and you can't just pack 'em up and fly 'em around."

"Don't worry," assured one gallery insider. "They'll be around here for a while yet."