Light & Colour Perception Light is necessary to our perception of colour. This is why we don’t see colours in the dark, only shades of grey. It‘s all based on the composition of light and how it is reflected. Light is composed of electromagnetic waves. Not all these waves are visible to the naked eye. Those that are, are what we perceive as visible light. Ultra-violet or infra-red electromagnetic waves are outside the visible spectrum for human beings and are therefore not visible. The visible spectrum range for humans is from 400 nm (nanometer) to 750 nm. Colour, or our perception of colour, is a result of the way in which an object absorbs and reflects light. The colour impression that our brain generates depends on which wavelengths of the visible light spectrum are reflected by an object. Why does a red apple appear red? Electromagnetic waves (light) hit the surface of the apple. In this case, the apple absorbs the remaining visual wavelengths and only reflects the red ones. This light enters the eye. Photoreceptors in the eye and the brain then read this stimulus as a colour. This is why we perceive the apple as red. This is the process by which we perceive all colours. If an image appears blue it absorbs the red, green and yellow wavelengths of the light and reflects the blue wavelengths. How do we perceive black and white? A black object appears black because it absorbs all the wavelengths, and reflects nothing. When all the colours are reflected equally, it creates what is referred to as white light. Admin’s- Jasdeep Kaur and Balwinder Singh, Teachers and Students Science Club (Biological Sciences Wing) For More Like this page: https://facebook/TSSCIENCECLUB
Posted on: Sun, 08 Jun 2014 11:37:57 +0000
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