We've had too many seasons of floppy clothes and dour colors. The eye gets tired of seeing the same thing, for God's sake," said designer Bill Blass in his sleek, gray showroom as he prepared for his showing of spring ready-to-wear.

Racks of clothes included bright red plaids, suits in Lifesaver colors, silk print gowns and an entire group in pink with brown. Hats came with huge, cartwheel brims; pumps, often in two colors.

Fit, for Blass, means clothes that show off the waist, clothes that are slim but not tight. "Nothing is uglier than a skirt that cups the rear. I never like that," said Blass, as a model turned to show off a straight skirt eased with low pleats.

The new, narrow clothes, according to Blass, have revived the slim reefer coat (Nancy Reagan already has bought a version for winter) and have brought new attention to lapels that sometimes appear to be askew (one lapel can be higher than the other), often in a color that contrasts with the coat or suit. Narrow clothes also have brought back military details, right down to brass buttons and bullion embroidery on sleeves and contour belts. "When things are precisely tailored, military details seem natural," said Blass.

Blass is still the master of evening clothes; he has chosen extraordinary prints from Abraham in Switzerland and Gandini in Italy. For Blass customers, the exit will be as significant as the entrance with as much going on in the back of the dress--marvelous ruffles, cutouts, pleats, poufs--as in the front. One slim dress bisected in black and white has a huge pouf to one side that one sees only as the model leaves.

Blass wanted all the models in his show to have short hair but relented on Jerry Hall, Mick Jagger's girlfriend, whose trademark is long hair. But he wouldn't agree to the demands of another model, Isabella Rosselini, Ingrid Bergman's daughter, whose fee would have been $5,000 to model in Blass' shows this week (Rosselini wasn't in the show).

The cost of the clothes, because of boosts in labor and fabrics costs, also concerns Blass. "There is a point where it is almost excessive," he says, but won't be specific about just where that point is. "But that's when I absorb some of the costs myself."

But not to worry about Blass. His Blassport sportswear collection, like his expensive things, is selling like hotcakes. And to add to his list of 32 licensees, he's just signed to do designer telephones.