the magic of colour
Colour is a function of the way our eyes see light.
Light is radiant energy which travels to us from the sun or different wavelengths. Each wavelength corresponds to a different colour in the spectrum. The reason why an apple appears 'red' is because it has absorbed all the wavelengths of light except the red, which it reflects back to our eyes.
Our eyes, however, are not infinitely sensitive. We can only see a portion of the spectrum - the extremes, ultraviolet and infrared, are invisible. The differing wavelengths also demand that the eye and brain make a constant series of adjustments.
During the day we see most effectively within the middle of the spectrum; in other words, the wavelengths which correspond to the colour green. Our perception of a green landscape as restful, and the reason why green blinds, green awnings and green tinted glass have traditionally been considered to be good for the eyes, arises from the physiological fact that our eyes have to adjust very little to see green.
The long wavelengths which correspond to the colour red, however, demand maximum adjustment, which is why the colour appears to leap out at us. Red is literally a shock to the system, a physical stimulus that is psychologically interpreted as excitement, arousal or alarm.
During the evening, when light levels are low, the spectral range we see most easily shifts slightly towards the shorter wavelengths of blue. Unlike the sudden imperative of red all the short wavelength colours from greens to blues to violets are inherently soothing and distancing.