FASHION : A Tough Act to Precede : Fall shows: In a week given over to the latest from Seventh Avenue, the best was saved for last with Geoffrey Beene’s designs, although others were certainly impressive too

NEW YORK —  Seventh Avenue saved the best for last, ending a week of fall fashion shows with Geoffrey Beene’s collection.

His clothes are the place where art meets reality in a balancing act that works better some seasons than others. This time it was just about perfect.

The daywear was typically futuristic feeling, with leather-belted jumpsuits under long, hooded coats, and long, body-molded gray tweed jackets over short, deeper gray tweed skirts.

In most other designers’ collections short is the only length that looks right for fall. Beene changed that when he opened his show with ankle-length dresses whose skirts flared to a full shape. He showed them with military-like, over-the-shoulder belts, and flat-heeled leather boots for a folkloric flavor taken from somewhere between the Russian Steppes and the Mongolian border. World news being focused on that part of the globe gave the dresses greater relevance which helped them hold their own against so many minis.

As usual, the details of Beene’s evening wear all but defied description. Crescent-shaped insets of sheer silk at the hip, quilted satin armor-like appliques at the shoulder blade, waistlines that conform to the body in front but stand away in back, fabric jewelry, floral embroidery, a mix of laces from fine to fuller scale, were the basic vocabulary.

Most of the clothes were cut close to the body. Among the best were a short, wine red lace sheath with a short jacket, and several body-molded slips that glimmered like black oil slicks.

But some of the most extraordinary dresses were ankle length, narrow fitted at the shoulders and very full at the hem. Several in muted floral prints looked especially new.

Beene’s intellectual artistry attracts some Hollywood actresses who have a similar image.

One of them, Sigourney Weaver, went back stage to say hello after the show. She is expecting her first baby this month.

Donna Karan has her fashion formula down pat--close-to-the-body clothes in luxury fabrics with sex appeal that nearly exceeds the legal limit.

For fall, she kept her signature Unitards or body suits, sarong skirts, elongated jackets and stretch pants. Her colors were black, white, and deep gray as well as coppery brown. She added some new shapes--a short, hooded dress with a snug bodice and a very full, dance skirt, a sequined cocoon-top over silky stretch pants, and enormous cowel necklines on tunics as well as swing coats. Alpaca and cashmere dominated for day, velvet and seed-beaded silk for night.

Women who collect Karan’s clothes could update the look by simply adding a pair of high-heeled shoe boots like those she designed for most of the new collection. They lace up the front, in suede for day or velvet for night. And they are real sizzlers.

Bob Mackie had a tough act to follow after last season’s Las Vegas-themed collection, with fan dancers and chorus girls as his inspiration.

For his show on Thursday, he used the tamer theme of American folk heritage. But somehow, he still managed to take it over the top.

The man can’t help himself--thank goodness.

After a week of shows that ended with variations on wedding gowns and veils, Mackie ended his with Indian chief headdresses over gold beaded gowns.

His John Philip Sousa marching band hats livened up some very curvy satin dinner suits. And his turn-of-the-century, madame librarian, party dresses with fitted bodices and fuller skirts were literally wrapped in gem-studded ribbon that tied in a party bow at the shoulder.

But the corker was a strapless, black velvet, body-hugging gown with a gold-embroidered eagle soaring skyward from the neckline. Nutty as it sounds, the dress was actually very witty and smart. It really worked.

Among the hoopla, Mackie slipped in a few classic jersey dresses and fitted wool crepe suits that anyone could wear.

In the three years since he opened his ready-to-wear line in New York, his shows have become a high point of the New York fashion week, for entertainment value alone.

At Anne Klein, Louis Dell’Olio cut his typically simple, contoured shapes in richer fabrics than usual for fall. Sculptural jackets are beaded tapestry, tunics and skirts are panne velvet or metallic silk. He is bringing back daytime dresses, some with empire waistlines and fuller skirts. All of them short, and worn with collarless coats in interesting color mixes such as forest green with warm apricot.

Dell’Olio excels at taking the best experiments by other designers and adapting them for the mainstream market.

This time he picked up on fashion medievalist Romeo Gigli’s rich fabrics.

Before his show, Isaac Mizrahi said he was going to broaden his range and try some new ideas. One of them turned out to be his first men’s wear collection.

The clothes are very unusual, yet they make perfect sense. There was a gray flannel tuxedo, and a double-breasted suit in camel cut wider than the traditional shape, but including all the required ingredients of officewear. Most styles looked like what Mizrahi himself would wear.

The women’s collection, the main event at Mizrahi, looked more grown up in some ways than what the 28-year-old designer has shown in the past several seasons.

A slip-like evening dress in mint green satin was cut so low in back, and stood so far away from the body, that you’d swear you could see everything. But through some marvel of engineering you really couldn’t.

Mizrahi’s single-button wrap skirt was as clean cut and energetic as a skirt can be, especially worn over white tights and turtleneck.

Evening pant suits in bold yellow velvet or quilted silk prints with Chinese overtones looked young and elegant.

Mizrahi fell short when things got too busy or looked overly improvised. A plaid “shawl” skirt with asymmetric hemline, for example, only detracted from the beautiful red flannel jacket with velvet string tie closing he showed with it.

At his best--and the backless slip dress in satin was among the best--Mizrahi welded nature girl and glamour girl for a fusion that was all his own.

Unlike many seasons, fashion here is individual and diverse for fall. The only musts are short narrow skirts.

Otherwise, the big name designers are being consistent and reliable by showing shapes and proportions they are already well known for.

By far the best collections of the season came from Ralph Lauren, Oscar De la Renta and Geoffrey Beene. When in doubt, start there.