NEW YORK -- A vintage Ultrasuede dress belonging to his mother prompted Geoffrey Beene to return to that practical synthetic. A collection of antique hats inspired Donna Karan to create a more ladylike, sometimes fragile-looking collection of clothes. But while both designers drew from the past, both came up with thoroughly modern collections in the season's final shows by New York designers for next spring.

Beene, in creating his collection, says he challenged himself to find the single most useful piece of clothing for women. He realized he had an Ultrasuede jacket he had worn for 10 years, and that the beige Beene Ultrasuede dress his mother had worn for 12 years still looked new hanging in his studio. People gave up Ultrasuede for natural fibers "because of snobbism," Beene says. "My use of it now is a gesture of antisnobbism."

He found the current incarnation of Ultrasuede heavier and drapier than the last time he used it, and made seven easy pieces -- short jackets and swing coats for daytime and evening, in bright colors and white. None of the items are lined, so they are all washable. "The point is performance," says Beene.

Beene is always looking for innovative fabrics -- this year he's discovered a stretch satin, the first stretch couture fabric, he says. "With stretch a dress is almost undesigned. It is so basic it takes no mental exhaustion," says Beene.

And while he is always pushing for chemists to come up with space-age synthetics, he makes classic fabrics look totally fresh. He has designed a lace to match the print of a dress, and another lace in clear Crayola colors. Menswear fabrics, such as shirtings and patterned silk normally used in ties, are used in a charmingly contradictory way by Beene in vests, for example, or very short jackets. "And all of these menswear fabrics are made in America, I'm happy to say," adds Beene.

Many of his dresses are topped with vests. "The vest is the single piece of clothing that can give a whole tone or change to what a woman owns," says Beene. He expects that women will move the vests around their wardrobes, teaming them with items besides those with which he shows them.

His clothes are all quite short -- several inches above the knee -- and many of the irts are quite full, no surprise since his big seller this fall is a tent-shaped dress in wool jersey. "By putting short dresses in menswear fabrics they have all the propriety of business daytime dress without looking masculine and tailored." Even when he shows long dresses they are ankle length, so they can be used on many more occasions than if they were all the way to the floor, says Beene.

This season, too, he continues the jump suit, a uniquely practical garment. "It is the most modern piece of clothing today. One zip. One gesture and it's on. It is one piece of clothing that performs in many, many ways. In black crepe with a halter front and a swimsuit back, it's the new ball gown."

Donna Karan's alternative to the ball gown is also pants, in almost sheer wool crepe with a draped stretch wool jacket. She figures she has given the executive woman a sensible formula for dress with bodysuits, short irts and easy jackets. Now her target is the woman who finds time to go to lunch.

Everything in the new collection is more sophisticated, more dressed up and more womanly than what Karan has shown in the past. Suits look like two-piece dresses with jackets that are draped at the waist or plunge in front. Some are decorated with a fabric flower. Some are paired with Bermuda shorts.

Karan has a penchant for sheer fabrics for spring, wool so sheer it is almost gauzelike and as see-through as the striped lace she likes as an alternative. Using lace in a daisy or carnation pattern, she makes a "twin set" from a black daisy lace bodysuit, worn with a matching lace short cardigan and stretch silk short irt. Stretch is used throughout, sometimes to assure a close fit; other times for comfort.

While concentrating on new shapes, Karan has confined her color palette mostly to midnight blue, natural, taupe and some touches of mulberry. No patterns here but lots of textures.

Karan's "ladies who lunch" clearly also go out to dinner, and for them there are very slim stretch wool crepe dresses to the floor. But not if they eat very much.