In 1666, English scientist Sir Isaac Newton discovered that when pure white light is passed through a prism, it separates into all of the visible colors. Newton also found that each color is comprised of a single wavelength and cannot be separated any further into other colors.

Further experiments demonstrated that light could be combined to form other colors. For example, red light mixed with yellow light creates an orange color. A color resulting from a mix of two other colors is known as a metamer. Some colors, such as yellow and purple, cancel each other out when mixed and result in a white light. These competing colors are known as complements.

[top]Color Psychology - The Psychological Effects of Color

While perceptions of color are somewhat subjective, there are some color effects that have universal meaning. Colors in the red area of the color spectrum are known as warm colors and include red, orange, and yellow. These warm colors evoke emotions ranging from feelings of warmth and comfort to feelings of anger and hostility.

Colors on the blue side of the spectrum are known as cool colors and include blue, purple, and green. These colors are often described as calm, but can also call to mind feelings of sadness or indifference.

[top]Color Psychology as Therapy

Several ancient cultures, including the Egyptians and Chinese, practiced chromotherapy, or using colors to heal. Chromotherapy is sometimes referred to as light therapy or colourology and is still used today as a holistic or alternative treatment.

In this treatment:

Red was used to stimulate the body and mind and to increase circulation.
Yellow was thought to stimulate the nerves and purify the body.
Orange was used to heal the lungs and to increase energy levels.
Blue was believed to soothe illnesses and treat pain.
Indigo shades were thought to alleviate skin problems.

Most psychologists view color therapy with skepticism and point out that the supposed effects of color have been exaggerated. Colors also have have different meanings in different cultures. Research has demonstrated in many cases that the mood-altering effects of color may only be temporary. A blue room may initially cause feelings of calm, but the effect will be dissipate after a short period of time.

Again more information on individual colors are as follows:

BLACK

Black is real sensation, even if it is produced by entire absence of light. The sensation of black is distinctly different from the lack of all sensation. -Hermann von Helmholz

[top]The Color Psychology of Black

Black absorbs all light in the color spectrum.
Black is often used as a symbol of menace or evil, but it is also popular as an indicator of power. It is used to represent treacherous characters such as Dracula and is often associated with witchcraft.
Black is associated with death and mourning in many cultures. It is also associated with unhappiness, sexuality, formality, and sophistication.
In ancient Egypt, black represented life and rebirth.
Black is often used in fashion because of its slimming quality.
Consider how black is used in language: Black Death, blackout, black cat, black list, black market, black tie, black belt.

WHITE

White...is not a mere absence of colour; it is a shining and affirmative thing, as fierce as red, as definite as black...God paints in many colours; but He never paints so gorgeously, I had almost said so gaudily, as when He paints in white. - G. K. Chesterton

[top]The Color Psychology of White

White represents purity or innocence.
White is bright and can create a sense of space or add highlights.
White is also described as cold, bland, and sterile. Rooms painted completely white can seem spacious, but empty and unfriendly. Hospitals and hospital workers use white to create a sense of sterility.

RED

Red has guts .... deep, strong, dramatic. A geranium red. A Goya red ... to be used like gold for furnishing a house ... for clothes, it is strong, like black or white. - Valentino

[top]Red

Red is a bright, warm color that evokes strong emotions.
Red is associated with love, warmth, and comfort.
Red is also considered an intense, or even angry, color that creates feelings of excitement or intensity.
Consider how red is used in language: redneck, red-hot, red-handed, paint the town red, seeing red

BLUE

[top]The Color Psychology of Blue

Blue is described as a favorite color by many people and is the color most preferred by men.
Blue calls to mind feelings of calmness or serenity. It is often described as peaceful, tranquil, secure, and orderly.
Blue can also create feelings of sadness or aloofness.
Blue is often used to decorate offices because research has shown that people are more productive in blue rooms.
Blue is one of the most popular colors, but it is one of the least appetizing. Some weight loss plans even recommend eating your food off of a blue plate. Blue rarely occurs naturally in food aside from blueberries and some plums. Also, humans are geared to avoid foods that are poisonous and blue coloring in food is often a sign of spoilage or poison.
Blue can also lower the pulse rate and body temperature.
Consider how blue is used in language: blue moon, blue Monday, blue blood, the blues, and blue ribbon.

GREEN

Green, which is Nature's colour, is restful, soothing, cheerful, and health-giving. - Paul Brunton
[top]The Color Psychology of Green
Green is a cool color that symbolizes nature and the natural world.

Grean also represents tranquility, good luck, health, and jealousy.

Researchers have also found that green can improve reading ability. Some students may find that laying a transparent sheet of green paper over reading material increases reading speed and comprehension.

Green has long been a symbol of fertility and was once the preferred color choice for wedding gowns in the 15th-century. Even today, green M & M's (an American chocolate candy) are said to send a sexual message.

Green is often used in decorating for its calming effect. For example, guests waiting to appear on television programs often wait in a “green room” to relax.

Green is thought to relieve stress and help heal. Those who have a green work environment experience fewer stomachaches.

Consider how green is used in language: green thumb, green with envy, greenhorn.

YELLOW
How wonderful yellow is. It stands for the sun. -Vincent Van Gogh

[top]The Color Psychology of Yellow
Yellow is a bright that is often described as cheery and warm.

Yellow is also the most fatiguing to the eye due to the high amount of light that is reflected. Using yellow as a background on paper or computer monitors can lead to eyestrain or vision loss in extreme cases.

Yellow can also create feelings of frustration and anger. While it is considered a cheerful color, people are more likely to lose their tempers in yellow rooms and babies tend to cry more in yellow rooms.

Yellow can also increase the metabolism.

Since yellow is the most visible color, it is also the most attention-getting color. Yellow can be used in small amount to draw notice, such as on traffic sign or advertisements.

PURPLE

[top]The Color Psychology of Purple
Purple is the symbol of royalty and wealth.

Purple also represents wisdom and spirituality.

Purple does not often occur in nature, it can sometimes appear exotic or artificial.

BROWN

[top]Color Psychology - Reactions to Brown
Brown is a natural color that evokes a sense of strength and reliability.

Brown can also create feelings of sadness and isolation.

Brown brings to mind feeling of warmth, comfort, and security. It is often described as natural, down-to-earth, and conventional, but brown can also be sophisticated.

ORANGE

Orange is very blatant and vulgar. It makes you immediately start having feelings.--Wolf Kahn

[top]The Color Psychology of Orange
Orange is a combination of yellow and red and is considered an energetic color.

Orange calls to mind feelings of excitement, enthusiasm, and warmth.

Orange is often used to draw attention, such as in traffic signs and advertising.

PINK

[top]The Color Psychology of Pink
Pink is essentially a light red and is usually associated with love and romance.

Pink is thought to have a calming effect. One shade known as "drunk-tank pink" is sometimes used in prisons to calm inmates. Sports teams sometimes paint the opposing teams locker room pink to keep the players passive and less energetic.

While pink's calming effect has been demonstrated, researchers of color psychology have found that this effect only occurs during the initial exposure to the color. When used in prisons, inmates often become even more agitated once they become accustomed to the color.