A colleague recently announced he had spent his weekend painting the baby`s room.

''What color?'' I asked quickly.

''Powder blue,'' he answered.

I breathed a sigh of relief.

Many expectant parents paint their baby`s room yellow-a nice, neutral color for an unborn baby whose gender is not known.

Not a good idea, color specialists say.

''Never paint a nursery yellow,'' said Carlton Wagner, director of Wagner Institute for Color Research, in Santa Barbara, Calif.

Yellow activates the anxiety center of the brain.

''In infants, it results in crying,'' he said. ''In adults, it results in shortness of temper. We notice a lot of fighting.''

Trying to lose weight? Paint your kitchen or dining room blue. You`ll spend less time eating. Researchers say the color blue makes us time-conscious and tends to curb our appetites.

''I recommend putting blue lights inside the refrigerator,'' Wagner said. ''You wouldn`t believe how unappetizing food looks in a blue light.''

Red, however, produces the opposite effect.

''We tend to eat more and eat longer in the presence of red,'' he said.

''That`s why you see a lot of red in restaurants.''

Bright reds stimulate glandular activity that helps us enjoy food and tends to make us lose track of time.

For a calming effect, go for soft, dusty peach, desert rose, greens and even some pale blues.

''Most colors that are calming have some gray in them,'' he said.

Bedrooms, on the other hand, require some analysis.

''It depends on how you use your bedroom,'' Wagner said. ''For a lot of people, it is a quiet retreat for reading, sleeping and doing crossword puzzles.''

For those who need help going to sleep, go for the soft colors, but avoid even the palest yellow if you want to get along with your spouse.

No matter how dark the bedroom is when the lights go out, the color of the walls affects sleep patterns, Wagner said.

''It`s the attitude it gives us before we sleep,'' Wagner said.

For romance, go for red. For security (say, if you`re single and living alone), go for autumn colors such as brown and rust. For a feminine touch, try peach with brown accents.

''I`ve always felt peach is very easy to live with,'' said Joe Ruggiero, publisher of HOME magazine and a regular contributor to the public television series ''This Old House.''

Ruggiero said eggnog also is a soothing color.

''Whoever`s in the room looks good,'' he said. -