Physcological Properties of Colour

Source: http://www.colour-affects.co.uk/psychological-properties-of-colours

RED. Physical Positive: Physical courage, strength, warmth, energy, basic survival, 'fight or flight', stimulation, masculinity, excitement.  Negative: Defiance, aggression, visual impact, strain. Being the longest wavelength, red is a powerful colour. Although not technically the most visible, it has the property of appearing to be nearer than it is and therefore it grabs our attention first. Hence its effectiveness in traffic lights the world over. Its effect is physical; it stimulates us and raises the pulse rate, giving the impression that time is passing faster than it is. It relates to the masculine principle and can activate the "fight or flight" instinct. Red is strong, and very basic. Pure red is the simplest colour, with no subtlety. It is stimulating and lively, very friendly. At the same time, it can be perceived as demanding and aggressive.
BLUE. Intellectual. Positive: Intelligence, communication, trust, efficiency, serenity, duty, logic, coolness, reflection, calm. Negative: Coldness, aloofness, lack of emotion, unfriendliness. Blue is the colour of the mind and is essentially soothing; it affects us mentally, rather than the physical reaction we have to red. Strong blues will stimulate clear thought and lighter, soft blues will calm the mind and aid concentration. Consequently it is serene and mentally calming. It is the colour of clear communication. Blue objects do not appear to be as close to us as red ones. Time and again in research, blue is the world's favourite colour. However, it can be perceived as cold, unemotional and unfriendly.
YELLOW. Emotional Positive: Optimism, confidence, self-esteem, extraversion, emotional strength, friendliness, creativity.  Negative: Irrationality, fear, emotional fragility, depression, anxiety, suicide. The yellow wavelength is relatively long and essentially stimulating. In this case the stimulus is emotional, therefore yellow is the strongest colour, psychologically. The right yellow will lift our spirits and our self-esteem; it is the colour of confidence and optimism. Too much of it, or the wrong tone in relation to the other tones in a colour scheme, can cause self-esteem to plummet, giving rise to fear and anxiety. Our "yellow streak" can surface.