Among the "warm" colors are red and orange. These are lively and tend to excite emotions and stimulate certain bodily functions. According to the book The Art of Color and Design, red light "accelerates the pulse and raises blood pressure." Persons who prefer red are often impulsive and energetic, with strong personalities and a craving for action and success. Properly used, red and orange can be stimulating, but overuse produces tension.
Another warm color is yellow. Bright, clear yellow reminds one of the sun and is cheerful, gay and lively. On the other hand, the darker yellows and greenish yellows are not popular. In the minds of many they suggest things such as sickness, cowardice, envy and treachery. But when properly related to other colors, these yellows contribute to a delightful overall effect.
The "cool" colors, including violets, blues and greens, are tranquil and serene. They have a calming effect upon people. In contrast to the results of red light upon humans, blue light has been found to retard the pulse rate and lower blood pressure. Light blue is soothing, suggesting blue skies and the waters of rivers and lakes. Light green is another restful color, reminding one of the outdoors.