If you should overhear someone telling a salesperson they have to consult their chart before buying, they may not be talking about their horoscope.

Their oracle could be a little packet -- whipped out of purse or pocket -- containing a few dozen color shades that best complement their skin, hair, eyes and lips.

Color consultants are not yet a household staple, even in California (where they originated about 20 years ago), and those not familiar with what they actually do are apt to have some strange misconceptions.

Says Washington color consultant Susan Straight, "I recently attended a party where I didn't know too many people. One woman came up to me and said, 'I heard you are a fortune-teller and do charts.'"

You might think that a color consultant will tell you never to wear olive green or mustard colored clothes. To the contrary: They believe that every man or woman can wear every color in the spectrum, but it must be a specific shade and clarity to best suit personal coloring.

"Everyone can wear every color," claims consultant JoAnne Nicholson, whose Northwest Washington living room rug is exactly the same ruby-red shade as her silk blouse.

"People often say that they can't wear yellow, or that green always sallows them. It's just that they don't have the right shade of green or yellow for their coloring."

It's the positive feeling about color -- remember a room bathed in soothing pink light or Elizabeth Taylor in a violet exactly matching her eyes? -- that color consultants hope to increase. (Rather than the negative, like visions of hospital-green walls.)

The Color I method of analysis is based on two huge trays containing more than 700 paint-chip colors, which are held up to the face. A "Personal Color Harmony Chart" of the chips is then made up for the client, as well as a purse-size model to be pulled out when he or she is in doubt about a certain purple jacket, a certain color of lipstick, or even a new sofa.

"The colors on your chart can be applied to anything around you -- clothes, makeup, interiors," says Nicholson, "so everything can be in your best shade."

Color I people divide the world into four basic color types: Contrast (ivory or olive skin, dark hair); Light-Bright (golden-toned skin, golden or golden-brown hair); Gentle (pale skin, ash-blond, ash-brown or red hair), and Muted (brown-beige or golden-beige skin and brown or red hair).

Consultant Straight has found that many of her clients are women re-entering the job market.

"Unless women know what colors are best, they tend to stick to boring neutral tones. Their color chart is a way for them to feel confident and better about themselves. And everything in their closet will go with everything else.

"It's a once-in-a-lifetime expenditure," she maintains, "comparable in price to one pair of shoes or a blouse.You are putting yourself in control of the color in your life and you will no longer have a closet of clothes you won't wear, or a drawer full of lipsticks you can't use."

Nicholson, whose clients now number about 800 a year, has color-charted lawyers, dentists, tennis pros and even rock stars. Rep. Bill Frenzel (R-Minn.) was charted after his wife Ruth told him how "it simplified her life."

"Two years ago I was wearing mostly beige, tailored clothes, and realizing that I was getting a little older and needed something to give me a lift," says Ruth Frenzel (a Light-Bright, whose favorite color is now emerald green). "The colors JoAnne picked out for me set me off and every combination of them helps me look my best."

She always carries her chart and that of her children. "I never have any trouble choosing an accessory, or something for the children because I know exactly the colors we already own."

"Color Me Beautiful" consultant Carole Jackson uses a fabric-draping method to determine the most becoming colors, based on categories of the four-seasons.

"People can't afford to waste money on things that don't look good," she says. "Some people have a color sense already, but some have been raised by a mother who was a completely different coloring and dressed them in her colors, so now they have lost touch with themselves."

Even though you've "had your colors done" (as it is referred to in the business), consultants insist you don't have to go out and spend more money on a whole new wardrobe.

"People always have some clothes in their closet that are right," says Jackson. "You don't throw away all of those that are not; you just make sure that everything new that you buy is the right shade for you. It usually takes three years to get your whole wardrobe changed over."

Of course, she says, there are women who will never again wear a color not on their chart.

Color consultants may not be the instant answer to everyone's wardrobe problems, but calling your color consultant before making a purchase could become as chic as checking in with your broker or astrologer. (If people finally figure out what it is they do.)

"I was scheduled to chart all of the Beach Boys a year and a half ago," says Nicholson. "One almost didn't come. He was afraid he was going to have to take off all of his clothes."