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Understanding colour
The whole experience of colour is influenced by light energy. Colour is not only seen but also 'felt' emotionally. These personal interpretations are what make colour such an intriguing field. In 1678, Isaac Newton discovered that white light/sunlight could be split into the colours of the spectrum, solving the mystery of rainbows. A rainbow is created when the sun's rays are refracted and reflected by the falling raindrops in a shower. The raindrops act as tiny prisms. Each prismatic colour has a different wavelength. The colour we see changes according to the angle that light is refracted and reflected from the surface. If light is not refracted when its rays hit an object, light is not split and white light is reflected. White light is made up of all the colours of the spectrum. We experience this reflected light as colour - or pigment. Pigment has the ability to absorb some wavelengths and reflect others. For example, when light falls on green grass, the surface absorbs the purple, red and orange parts of the spectrum and reflects only the green. The wavelengths that the surface reflects determines its colour. The more of the spectrum the surface reflects, the closer it appears to white. The more it absorbs, the closer it appears to black. Perception of Colour In the world of nature, the dawn chorus begins when the required amount of light stimulates the cones in a bird's eye. Our perception of colour can be affected by chemical changes in the body caused by sickness, age or drugs. Cataracts that can form on human eyes as they age soften and 'blur' colour so that 'pastels' and mid level colours may appear nearly white. The human brain reacts to colour as it receives different wavelengths through the eye. Red is more stressful because it has longer wavelengths that require more adjustment by the eye. In contrast, green is restful because the eye needs almost no adjustment to receive and pass the colour message by the eye. Light primaries - Red, Green and Blue - are the colours picked up by the receptor cells in the human eye. These cells respond to the primaries and mixtures of them and send minute electrical currents to the brain and the sensation of a coloured picture is the result. The total combination of red, green and blue lights gives a total effect of white. This is called additive mixing.
Pigment primaries are Red, Yellow and Blue. In the print industry, magenta, yellow and cyan (blue-green) are used as pigment primaries. These colours cannot be obtained by intermixing other colours. When they are at full saturation it is possible by intermixing them to obtain the remaining colours of the spectrum. These three combined give a total effect of black. Impurities in pigments cause the results to be a deep dirty grey. As colour is being taken away, this is called subtractive mixing. Each time colours are intermixed the result will be duller and dirtier than the original colours. This is seen when mixing secondary and tertiary colours from the three primary colours. Black, white and grey are referred to as neutrals or achromatic colours. Used to tint, shade and tone colours, they have a positive influence on all hues and are termed 'colours' in the liberal meaning of the word. When nine greys are arranged in a graduated scale ranging from white to black, it is referred to as a grey scale. A grey scale (sometimes referred to as a reflective scale) is the backbone of colour systems. It is used to measure the corresponding values of chromatic colours and to develop colour schemes that have carefully arranged value steps. |
Light, stimulating the retina of the eye, is
what creates our perception of colour. Without light there is no
colour, and light reflects how we see colour. Because colour is
so powerful we tend to look for rules for its use, but there are
no hard and fast rules. How you use colour is a very individual
and creative choice, but understanding how colour works will help
you use it more effectively. 
