Red has been shown to raise blood pressure and speed respiration and heart rate. It is usually considered too stimulating for bedrooms, but if you're only in the room after dark, you'll be seeing it mostly by lamplight, when the color will appear muted, rich, and elegant. Crimson can make some people feel irritable; if you love red but it bugs your mate, try small touches in accessories or upholstery fabrics.
Orange, like red, stimulates appetites. In its pure form, however, orange may be a difficult color to live with. Terra-cotta, salmon, peach, coral, and shrimp are more popular expressions of the hue. Peach is nurturing yet restful in a bedroom; in a bathroom, it flatters light skin tones. Orange shades imbue a living room or family room with warmth and energy. In a kitchen that faces west, however, orange tones may feel unpleasantly hot.
Yellow captures the joy of sunshine and communicates happiness. It's perfect for kitchens, dining rooms, and bathrooms, where happy color is energizing and uplifting. In halls, entries, and small spaces, yellow can feel expansive and welcoming.
Green is considered the most restful color for the eye. Combining the refreshing quality of blue and the cheerfulness of yellow, green is suited to almost any room in the house. In a kitchen, a sage or medium green cools things down; in a family room or living room, it encourages unwinding but has enough warmth to promote comfort and togetherness. In a bedroom, it's relaxing and pleasant.
Blue brings down blood pressure and slows respiration and heart rate. That's why it's considered calming, relaxing, and serene, and is often recommended for bedrooms and bathrooms. Be careful, however: A pastel blue that looks pretty on the paint chip can come across as unpleasantly chilly when it's on the walls and furnishings, especially in a room that receives little natural light. If you opt for a light blue as the primary color in a room, balance it with warm hues in the furnishings and fabrics. To encourage relaxation in the rooms where people gather -- family rooms, living rooms, large kitchens -- consider warmer blues, such as periwinkle, or bright blues, such as cerulean or turquoise.
Purple in its darkest values (eggplant, for example) is rich, dramatic, and sophisticated. It's associated with luxury as well as creativity, and as an accent or secondary color, it gives a scheme depth. Lighter versions of purple, such as lavender and lilac, bring the same restful quality to bedrooms as blue does, but without the risk of feeling chilly.
Neutrals (black, gray, white, and brown) are basic to the decorator's tool kit. All-neutral schemes fall in and out of fashion, but their virtue lies in their flexibility: Add color to liven things up; subtract it to calm things down.
Black is best used in small doses as an accent -- indeed, some experts maintain that every room needs a touch of black to ground the color scheme and give it depth.