Scene Stealers : New Year’s Eve isn’t just any night in the world of movies. Uh-uh. It’s the night the designers pull out all the stops-and then some.

The New Year’s Eve scenes in the movie “Sunset Boulevard” may take place in a gloomy, cavernous living room, but they have style. Gloria Swanson is stunning in a black tulle gown and real diamonds. William Holden is the epitome of elegance in custom-made white tie and tails. And a solid gold fob.

Keep your eyes on the fob. Later that night, as Holden--an exquisite vicuna coat added to his ensemble--tries to escape from the lovesick Swanson, the fob catches on a doorknob, ensnaring him. He pulls free, but from that moment his fate is sealed.

In “Sunset Boulevard” and dozens of other films, New Year’s Eve is never just a party night. It is the night that plots take 90-degree turns and costumes stand out like beacons.

Billy Crystal quickly spots Meg Ryan in a royal-blue dress as he rushes into a crowded ballroom to propose marriage--at last--in “When Harry Met Sally.” And Michelle Pfeiffer sizzles in red velvet atop a grand piano as her career and love life take off in “The Fabulous Baker Boys.”

In Paul Mazursky’s “Tempest,” black velvet, gold lame and white plumage push brooding architect John Cassavetes over the edge and off to simpler pleasures in Greece. And in “The Poseidon Adventure,” cruise-ship passengers--Shelley Winters, Stella Stevens, Red Buttons, Gene Hackman and Ernest Borgnine among them--battle for survival in their party clothes.

Edith Head died in 1981, but her former assistant, June Van Dyke, fondly recalls Swanson’s strapless New Year’s Eve gown “with that marvelous bit of tulle around the shoulders.” And her jewels were divine. “Some of them were real and they were Gloria’s,” she says.

“Edith was the greatest at creating the characters through their clothes. And when she dressed Holden in a vicuna coat and tails, he was drop-dead gorgeous. It was through the clothes that he was transformed from a newspaper hack into a very sophisticated escort.”

Van Dyke, who inherited a beaded jacket Swanson wore in the 1950 film, remembers her first encounter with the actress. It was at a dinner party in Head’s home, to which Swanson, who had “terrible stomach problems,” brought her own food in crystal jars with monogrammed sterling silver lids.

“I was stunned when I met her,” Van Dyke says. “She was very tiny, maybe five feet tall. She had tiny hands and feet, but she had a large head and a gorgeous Roman nose. When she spoke, she spoke right into your eyes and she mesmerized you. And then, almost like being directed, she would turn right and left and give you that dazzling profile.”

Swanson’s tiny frame never caused design problems, Van Dyke says. The actress wore custom-made platform shoes and “the way she handled herself made her look 5-foot-8.”

Bill Thomas, a Burbank-based broker and curator of Hollywood memorabilia, says the “Sunset Boulevard” costumes were a joint effort. “Both Edith Head and Gloria Swanson worked on them. After the film, Gloria went on to create her own (retail) label.” But the dress line, to which Swanson did little more than lend her name, failed.

The New Year’s Eve scene in “That Hamilton Woman,” a 1941 film starring Vivien Leigh and Laurence Olivier, holds special importance for Thomas. He once owned the gown Leigh wore--a period piece, designed by Rene Hubert, in silk panne velvet and silk chiffon, and hand-embellished with tiny crystal beads and rhinestones.

Thomas, who estimates that the gown would cost $24,000 to make today, auctioned it off in 1984 for about $1,200: “It’s value was diminished. It had been altered--beyond the point where we could restore it to the original--for Ann Sheridan to wear in ‘Shine On, Harvest Moon.’ ”

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He also bought and sold the wardrobe from the 1989 film “The Fabulous Baker Boys,” except “ that dress,” he says. The matching red fabric shoes went for $200 to a collector.

The dress turned up in a 1990 exhibition at the Fashion Institute of Design and Merchandising in New York, but Thomas says: “I don’t know who it came from. Someone had the foresight to save it. Maybe Michelle herself. The scene was a great moment in her career. All the reviews mentioned it. So that dress holds importance.”

The film’s costume designer, Lisa Jensen, whose most recent screen credit is “Grumpy Old Men,” says Pfeiffer didn’t keep the dress. But one thing is sure: It helped turned the actress into what one critic called “the screen’s reigning goddess.”

“She had to move in the gown in a way no woman in her right mind would move in a dress like that,” Jensen explains. “She had to sing to the audience, sing to (Jeff Bridges as Jack Baker), then crawl up on the piano.”

Jensen estimates that Pfeiffer wears the silk-velvet sheath “for a total of 10 to 15 minutes.” Then Bridges unhooks it--on screen. The pivotal back fastener was an antique clasp Jensen’s mother had bought years earlier at an East Coast flea market.

In contrast, the New Year’s Eve finery in 1989’s “When Harry Met Sally,” is “pretty straightforward,” says costume designer Gloria Gresham, whose credits include “A Few Good Men” and “Ghostbusters II.” “People are dressed for New Year’s Eve in New York City.”

Except for Billy Crystal, as Harry, who bounds onto the scene in blue jeans and sneakers. “Meg is all done up,” Gresham says. “The idea is to have a strong juxtaposition between the two. As far as what Meg wore, we felt it shouldn’t be another black dress.”

So the dress was blue--purchased in a forgotten store, “torn apart and put back together again.” Carrie Fisher, in the role of Ryan’s best friend, “got the black dress,” a chiffon sheath from her own closet. “We had to be careful with it,” Gresham says. “There were places where it was beginning to get holes. But it seemed to suit her perfectly.”

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Gena Rowlands got the black dress in the 1982 film “Tempest.” “It had to be very elegant, very dressed up. You can’t go wrong with black velvet,” costume designer Albert Wolsky says of the bare-shoulder gown.

The movie begins on New Year’s Eve in New York, and the party scene is filmed on a magnificent circular staircase. At midnight, the rich and famous guests are showered from its apex with exotic feathers.

“That whole party was a metaphor for the suffocation (Cassavetes) was feeling,” Wolsky says. “He didn’t like all the glamour, the chitchat, the party talk.”

To enforce the glamour, Wolsky, whose Oscar credits include “Bugsy” and “All That Jazz,” avoided certain shades, particularly bright blue, which he calls a cheap color. “And I didn’t want men in those blue shirts. I didn’t want them to look like people out of a band. Everyone had to look as rich as possible. No frills. No red ties.”

Paul Zastupnevich went for frills and sex appeal in 1972’s “The Poseidon Adventure.” His Oscar-nominated costumes included a ruffled-front, ruffled-cuff tuxedo shirt for Red Buttons, a vacationing haberdasher, and a slinky, Jean Harlow-inspired gown for Stella Stevens, portraying a former hooker.

At Stevens’ request, and against his better judgment, Zastupnevich says he designed a gown for the actress that revealed too much cleavage “for a family picture.” When producer Irwin Allen objected, Zastupnevich added a rhinestone clip that “fans out like a turkey tail.” It filled in the decolletage and kept Allen from scrapping the dress.

As might be expected in a film version of the New Year’s Eve from hell, there were wardrobe problems. In a scene in which Shelley Winters is hoisted by a fire hose, her pearls must break. It required 24 takes and 12 strands of pearls, which had to be restrung between takes, to get the scene right, Zastupnevich recalls.

The actors sometimes worked in a water tank, and their clothes, which should have been filthy, “would come out clean,” the designer says. “The final garments had to be pummeled and sprayed with paint to make them look as if they were dirty and greasy.”

But the greatest challenge was keeping Winters and the “bar mitzvah dress” he designed for her in place. The actress, who wore foam rubber padding to make her look more grandmotherly, “did her own stunt work,” Zastupnevich says. “Every time she would dive into the tank, she would bob back up. Finally, we had to put lead weights around her on a diver’s belt and weights around the hem of the dress so it wouldn’t flare up.”

Times research librarian Julia Franco contributed to this story.