Spring fashions

Name your fashion preference, and you could nearly always find it. Diversity was a ruling principle at recent American showings for next spring and summer. From Botticelli-like Renaissance at Mary McFadden to shipshape nautical at Gloria Sachs, inspiration was drawn from many different sources. The color blocks of the Dutch painter, Piet Mondrian, translated into famous dresses by Yves Saint Laurent in the 1960s, have been reinterpreted in suit form for 1984 by Oscar de la Renta.

The chemise, the trench coat, and the bush jacket have all been given new leases on life. The latest versions are often of linen. It's the star fabric for warm-weather months ahead, and never mind the wrinkles.

There's a lot of exuberant color (brilliant, clean tones as well as some unusual pastels), yet the overall mood is restrained. No-frills dressing is definitely on for the coming season. But while keeping within a general framework of uncomplicated, easy styles, US designers are going their separate ways.

Hemlines, for instance, (which aren't supposed to mean much anymore but remain a consequential matter to many women) are wildly divergent. Knee lengths prevail for day in the luxury-class collections favored by the limousine set: Bill Blass, Geoffrey Beene, and Halston.

On the long side are such trendmakers as Ralph Lauren, Perry Ellis, Calvin Klein, and the house of Anne Klein, where hems go anywhere from midcalf all the way down to the ankle. Bill Haire and McFadden are pro-long, too.

Women who are looking for guidance should, however, note that short skirts are also prevalent in reasonably priced lines: coordinates geared to the working woman by Eleanor Brenner, for example, and separates in handsome tattersall checks or ticking stripes at Liz Claiborne (whose clothes, which seldom cost more than $150, have been characterized as ''what the real people wear'').

Whatever dilemmas skirt lengths may pose for daytime, in the evening there's no problem. Practically every designer likes dinner and dance dresses that show off legs. The point is made at Geoffrey Beene with filmy patterned stockings that complement the delicate fabrics of his late-day clothes.

Both dresses and suits are in good supply for spring and summer. The most visible dress style is the chemise, which no longer has the baggy appearance of its earlier incarnation. Although it is loose around the waistline, its lines are usually narrow as an arrow.

Some new dresses are topped with big white collars. Many chemises have deep or shoulder-width armholes to lend emphasis at the top, and some are bloused in back. When belted, most dresses - short or long - are sashed about the hips. The importance of this part of the anatomy was underlined by Halston's models. They tied his new flowered intarsia cardigans low at their waists instead of around their shoulders, a look Halston started.

Relaxed sportswear is still the basic mode, so the severely tailored suit is a vanishing species at the moment. The offhand effect of unmatched jackets and skirts - where one texture or coordinated pattern is played off against another - carries on in three- and four-piece combinations. At Kasper, the jacket, vest, blouse, and skirt may range in tone from terra cotta to apricot and ecru. Pinafore tunics over linen dresses are his new alternative to suit dressing.

Separate pieces, extensively dealt with at Liz Claiborne, continue to appeal for day-to-day wear. Among her offerings are chalk-white and pastel summer chambrays. The soft colors, she says, ''are the ones the Concorde uses for their napkins on the plane.''

Other news notes included the prevalence of polka dots - the larger the better - which, like stripes of every possible dimension, have plenty of cachet for spring. Reversed patterns or different sizes of same are often used for split-color or mixed-print effects.

Despite the splashes of color, black and white is keeping its chic status. The little black dress comes in numerous versions, above the knees at Blass and cowled at the neck at Halston - a style some are calling ''the Crumbcatcher.''

Expensive simplicity, or the look of it, being the order of the day, glitz was at a minimum. So was stiff, architectural design. Ronaldus Shamask, its leading proponent, has abandoned his monastic vein for fluttery, unevenly layered numbers.

Still, Blass gives his customers brilliant prints picked out with pailletted motifs for evening, and Halston has a series of gowns of abstract-designed sequins and pearls.

Ruffles are rare, except at Oscar de la Renta, where flurries of vivid taffeta complete the collection. But you could hardly expect him to give them up when ''Ruffles'' is the name of his new $170-an-ounce perfume, could you?

As to the rest - Ralph Lauren, Perry Ellis, and Calvin Klein - their romantic visions of today's fashion are a thing apart. What they do has the most telling effect on the mainstream of fashion, and they merit a separate story.

More about them in our next report Tuesday, Dec. 6.