## How does Human Eye Perceive the Colour?

Basically, human eye and brain together convert light into colour. Light receptors within the eye pass on messages to the brain, which produces the familiar sensations of colour. For measuring ability of perceived colour depends on Colour Rendering Index (CRI).

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Let’s take one example of apple, light goes from the source (i.e. the sun) to the object (i.e. the apple), and finally to the detector (i.e. the eye and brain).

##### Must Read: What are Warm and Cool Colours?

Firstly, all the “invisible” colours of sunlight flow on the apple. Then the surface of a red apple absorbs all the coloured light rays, except for those related to red, and reflects this colour to the human eye and finally the eye receives that reflected (red) light and sends a message to the brain (Red apple).

Colour generally originates in light and the sunlight we perceive is colourless. But in reality, the group of colours that we can see with a prism or in a rainbow is called the colour spectrum. These colours always appear in same order i.e: red, orange, yellow, green, blue, indigo, and violet.

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As we know, sunlight is made up of the whole range of colours that the eye can perceive. The range of sunlight colours, when combined or mixed togather looks white to the eye. This property of sunlight was first demonstrated by Sir Isaac Newton in 1666.

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In this activity, we shine a light in just the right way on a glass prism, the light enters the prism, bends (or refracts), and spreads out, showing us all of the colours of a rainbow.

Usually Humans are better at discerning colour than most mammals, but plenty of animals beat us out in the colour vision department! many fish and birds have four tpes of cones enabling them to see ultraviolet light or light with wavelengths shorter than what human eye can perceive. Even some insects can also see in ultraviolet which may help them to see patterns on flowers that are completely invisible to us!

Note: Cones are the one type of photoreceptor, the tiny cells in the retina that respond to light. Most of us have 6 to 7 millions of cone & almost all of them are concentrated on a 0.3 millimeter spot on the Retina called the fovea centralis.

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