A World Without Colour

Firstly, we must realise how our eyes process colour. The human eye and brain together translate light into colour. This is done when light travels into the eye, to the retina (which is located on the very back of the eye). Since the retina is covered with millions of light receptive cells called rods and cones, these detect light and send complex signals to the brain [1]. Usually people have three cone cells and each colour can stimulate more than one cone. Therefore, the cells then produce a combined response for each colour, and distinguish them (nerve cells also help process the information at the same time) [1].

A world without colour. Just imagine it. All of your food, the spectacular sights and nature you see when you go on holiday, your family, friends, and everything else; colourless. Colour is what gives character to our planet, evokes memories and creates emotion. Without it, the world would be achromic (having no colour except black, white, or shades of grey) [2].

But how do our eyes really process colour, and why are certain things certain colours?

The way that colour is processed using our eyes, brain and various cells are so fascinating, and more is yet to be discovered. Researchers estimate that the human eye can see around one million different colours if it is healthy and that it can also perceive more variations in warmer colours than cooler ones! [1]

However, about 8% of men and 1% of women have some kind of colour impairment [1]. This leads to them perceiving colour uniquely – usually the colours they perceive as identical have slight differences that are only visible to others. The most common impairment is red and green dichromatism which causes the colours red and green to appear indistinguishable [1]. There are impairments that affect other colour pairs as well. On the other hand, total colour blindness is very rare, but sometimes occurs due to age and extreme exposure to chemicals such as styrene.

Oddly, birds, fish and many mammals can perceive the full spectrum of colour and some insects such as bees can view ultraviolet colours that are invisible to human eyes [1].

These abilities are very helpful in the wild where such survival skills come in handy between a predator and its prey: to camouflage and hunt. In addition, the myth that dogs cannot see any colour is false as they possess two types of cones that discern blue and yellow (dichromatic vision) [1].

Overall, there is so much to learn about colour, and a world without any of it would be quite strange. Colour is what brings life to our planet and helps creatures survive in the wild. We see colours in fascinating ways and those who can’t do so have impairments or are completely colour blind. Although we don’t always appreciate it, colour is found in art, emotions, nature, and basically everything else! It can sway thinking, change actions, and cause reactions. It can also increase blood pressure or suppress an appetite. When used in the right ways, colour can even save on energy consumption. As a powerful form of communication, colour will always be irreplaceable.

References

[1] Pantone. How Do We See Color? [Internet]. Pantone.com. 2021

[cited 2022 Jun 18]. Available from: https://www.pantone.com/articles/color-fundamentals/how

[2]Coelho A, Field SQ. Why is milk white? Chicago Review Press; 2013

Shaivi Kalwani 7ASY