Colour Psychology

Colours in the red area of the sprectrum are known as warm colours and include red, orange and yellow.  These can evoke emotions ranging from warmth and comfort to anger and hostility.
Colours in the blue area of the spectrum are known as cool colours and include blue, purple and green.  These colours are often described as calm, but often call to mind feelings of sadness or indifference.

Some associations for popular colours:

Black - often used as a symbol of menace or evil, but also a popular inidcator of power.  Associated with death amd mourning in many cultures, as well as unhappiness, sexuality, formality and sophistication.  Often used in fashion.
White - represents purity or innocence, and can create a sense of space or add highlights, because of its brightness and clarity.  Also often described as cold, bland or sterile.
Red - a bright, hot colour that evokes strong emotions.  Associated with love, warmth and comfort, but also anger and hatred - all heated, passionate feelings.
Blue - calls to mind feelings of calmness and serenity.  Often described as peaceful, secure and orderly, but can also create feelings of sadness or aloofness.
Green - symbolises nature, health, tranquility and luck, but also jealousy.  Green is also a symbol of fertilty, and has a calming effect.
Yellow - bright, cheery and warm, representative of the sun.  Can also create feelings of frustration and anger.  Yellow is the most visible colour, and the most noticeable, and can increase the metablosim.  Yellow is the colour most fatiguing to the eye, because of the amount of light reflected.
Purple - symbol of royalty and wealth, and also represents wisdom and spirituality.  As it does not often occur in nature, purple can seem exotic or artificial.  Also often associated with chocolate.
Brown - a natural colour that evokes a sense of strength and reliability, but can also create feelings of sadness and isolation.  Brown brings to mind warmth, comfort and security.  It is often described as natural, down-to-earth, and conventional.
Orange - a combination of red and yellow, considered an energetic colour, and is often used to draw attention.  Calls to mind feelings such as excitement, enthusiasm and warmth.
Pink - essentially a light red, associated with love and romance.  Thought to have a calming effect initially, but this wears off after exposure to the colour.