"Gee, that's a beautiful jacket," says Alexander Julian as a customer at Georgetown's Britches slips into a Julian design, a tan jacket with barely visible fine lines of numerous colors.

"You've just covered up two beautiful sweaters," says Julian, gently chiding another customer who has placed a navy blazer over two Julian-label argyle sweaters that incorporate at least a dozen colors.

If Julian is fishing for compliments for his menswear designs, it's hardly necessary. His face and label may not be as familiar as those of Ralph Lauren, Calvin Klein and Bill Blass, who design menswear as well as clothes for women. But his subtle coloring and patterns set his clothes apart, and he's won almost every menswear award possible, including three Coty Awards and the Cutty Sark Award. Soon he will get an award from the Council of Fashion Designers of America.

"The most important thing about fashion is to enjoy it," says Julian. "Don't take it seriously."

Julian has just signed a contract to do shirts for Cluett Peabody (Arrow shirts), and his growing business now generates about $25 million in retail sales, a small part in clothes for women.

His clothes are worn by such personalities as Charlie Rose, Ted Koppel and Barry Manilow, and Nicol Williamson has just acquired his things to wear in his next film.

Recently, in just a few hours, Britches sold more than $20,000 worth of Julian clothes.

It's understandable why Julian enjoys fashion.

Alexander Julian, 33, red-bearded, is sitting deep in a sofa toward the back of Britches, his eye catching the many customers who are trying on his clothes. But he is his own best model. He's wearing a navy Shetland blazer, but if you look closely there are 10 different color nubs or specks in the fabric. "Perfect for people with dandruff," he says, laughing.

His shirt is cotton with a 13-color graph plaid, inspired by Kandinsky, he says. The silk rep tie in broad stripes has an almost satin sheen, "only because I haven't spilled gravy on it yet."

Asked for a demonstration on how he stuffs the yarn-dyed linen square in his pocket, he explains, "You start with the southeast corner . . ."

His clothes are better than his humor. They are what he calls "modern traditional," with natural shoulders, full chest and a suppressed waist. "American men have their own shoulders and don't need any padding," he says. "And it would be funny to expect someone who doesn't take care of his waistline to take care of their necktie."

Julian designs and colors his own textiles; most of the current fabrics were made in Scotland, the others in Italy and Japan. "Color gives you the chance to display your own personal taste, your intellect, your values, your own sensitivities," he says.

"You either see no color or too much color in clothes; these come some place in between," says attorney Bill Henry, a former member of the Federal Communications Commission, who was trying on the Julian clothes at Britches recently.

Color has always been important to Julian. He once ran for the city council in Chapel Hill and suggested a director of esthetics for the city. He lost but was appointed to a Chapel Hill appearance committee and got the buses painted khaki with black and brown stripes. The transportation director got even by having all the bus seats colored Day-Glo orange.

Julian pulls back at the suggestion of preppie overtones to his clothes. But, with Chapel Hill in his upbringing, he comes from that bastion of classic southeastern traditional attire. In fact, his father's shop, called Julian's, on Franklin Street in Chapel Hill, had a lot to do with setting the Ivy League mood of the college and the town in the 1930s. "The most physical way you could show you belonged to the Ivy League was to wear it," says Julian. "Clothes gave students a way to out-Ivy League the Ivy League."

(His uncle had a lower-priced menswear shop across the street but because of a family feud of 27 years that ended only recently, Julian never even knew what that shop carried, he says.) At age 12, he had the store tailor switch the collars on his blue oxford button-down and yellow oxford button-down shirts. At 15, he had the tailors at Daks in London make up a jacket to his own specifications. At 16, he became the store manager for his father after school and on weekends. At 21, he had his own shop, Alexander's Ambitions. If it was too avant garde for the local clientele, it provided the showcase for his own designs, which led to a contract with a large menswear manufacturer.

So if he graduated from the University of North Carolina, his business education came from his father, "and my mother made me feel free to use it," he adds. Now he is doing the same for his 12-year-old daughter, Alystyre. This summer Julian and his wife, Lynn, took her to Paris "to begin her education proper," he said. They stayed at the Ritz. "And when I'd announce that we were going off to the Louvre, she'd ask to go back to Les Halles to shop for more clothes." Looking surprised, Julian adds, "She's got terrific taste in clothes."

He calls his own taste in clothes "self-indulgent." At a meeting of advertising executives on Madison Avenue, the 10 other men present were wearing what Julian calls "somebody-just-died suits."

"I was wearing one of those 10-color, pink argyle sweaters, pleated denim trousers, Topsiders and no socks. It relaxed them a lot," he says. "They all said they wished they could dress that way."