The answer to the question 'what is colour?' may seem simple on the face of it, but did you know that our eyes can only actually detect three colours: red, green and blue? It's the way that they combine that enables us to discern many more. By mixing red light and green light, for example, we can see yellow. And if all three are mixed together we see white light. The ways in which we perceive colour are important too, relying on a combination of vision and light, as well as individual interpretation. The way we see colour depends on physics, biology and psychology all interacting simultaneously.

The physical component of colour is all to do with light. The light that reflects off an object is the colour that we see, and different objects absorb and reflect light in different ways. The surface of a lemon, for example, reflects yellow light while the other colours are absorbed and therefore not visible.

The biological element of colour hinges upon how our eyes interpret the wavelengths of visible light. Those messages are then transferred from the outside world to our brains. The cone cells in the retina detect different frequencies and start to “colour-in” the world around us.

The psychological aspect of colour has a lot to do with perception. While perceptions of colour are somewhat subjective, and based in part on experiences and memories, some colours have universal meaning. Warm colours such as red, orange, and yellow evoke emotions ranging from feelings of warmth and comfort to feelings of anger and hostility, whereas cool colours such as blue, purple, and green are often described as calm, but can also call to mind feelings of sadness or indifference.

Colour and our perception of it is complex, and while colour can influence how we feel and act, these effects are subject to personal, cultural, and situational factors. Colour can impact performance, affect mood, inform consumer purchases, and much much more.

Sources:

1. Very Well Mind.
2. BBC Worldwide.
3. BBC.