How Do Colours Work?

Posted by on Jun 14, 2019 in News
How do colours work?

The planet Earth revolves around colour and our ability to perceive it. Artists, companies and fashionistas rely on their own ability to see colour and everyone being able to perceive it in the same way they do. But how do these colours actually work? How do we see different colours? In this article, we explore the biology behind our ability to perceive colours.

Humans have a deep-rooted relationship with colours; it’s ingrained into our DNA and reinforced during our formative years. Red is a bad colour, it means something is hot, or something is not allowed. Green is earthly and friendly, whereas blue is calming. These colours are used for similar reasons with companies, who chose their branding based on how they want their company to be perceived by the outside world, often conforming to basic colour instincts.

An Eye for An Eye

The human eye is the complex machine that allows us to see colour, relaying the information to the brain for us to perceive our surroundings in real time. The process starts with the outer layer of the eye, the cornea, which is the first to receive the colour information that we are looking at. The cornea is responsible for bending the light towards the pupil, which then dilates or contracts depending on the amount of light that is being perceived. Having passed through the pupil, the light is sent to the lens which angles the light towards the outler layer of the retina in a focused beam.

Rods and cones are light sensitive cells located in the outer layer of the retina which are responsible for processing the light information. Rods process how light or dark something is, whereas cones are the cells that allow us to see colour variety. Cones can be found in three different varieties, one for green colours, one for blue and one for red. These work by processing the different wavelengths of the light, with violet being the shortest wave and red being the longest. The information is then relayed to the optic nerve, which passes this to the brain.

Visible Light Spectrum

Much of the world around us is governed by waves and wavelengths, not that this is particularly visible to us. The electromagnetic (EM) spectrum is a chart that details the lengths and frequencies of all waves that fall under this banner, ranging from the shortest and most frequent (gamma rays) to the longest and least frequent (radio, TV and beyond). The visible light spectrum is a small subsection of the EM spectrum that details the range of colours that are visible for humans to see, based on the cones in our eyes. The range falls between ultraviolet and infrared with violet waves measuring roughly 400 nanometers and red measuring 700 nanometers.

The frequency of a wave is measured in Hertz, often used in multiple forms such as kilohertz, megahertz or gigahertz. These are often associated with radio and other audio applications, or the speed at which electronic devices can be driven. The frequency of the colour waves is so spectacularly high that it is impossible to perceive the wave shape with the human eye, rather, we just see a block of colour.

Colour in the World

Where business is concerned, colours are always chosen specifically, whether to convey a certain emotion or provide a certain atmosphere. When designing logos, websites, magazines, clothing, films and TV, and all other commercial products, colour plays an important role. For the most part, humans are described as trichromats, meaning we have three working cones in our retinas, allowing us to perceive red, green and blue light. This means that we can roughly see 1 million different colours. Tetrachromats are the lucky ones, they have inherited a DNA defect, meaning they have four types of cones and can see an estimated 100 million colours. That said, because this condition is so rare, people could potentially be unaware that they have inherited it. Additionally, because our brains are wired to work with three cones, it would take repetition and rewiring of the brain to make any difference to colour perception. Finally, because of our inability to communicate our experiences of colour with other people, we are completely ‘left in the dark’ as to what tetrachromats can see.

If you’re colour blind, it is because you are a dichromat, meaning you have inherited a DNA defect affecting one of the types of cones, allowing you to see roughly 10,000 colours. Although 10,000 can sound like a lot, colour blindness often affects the perception of the colour green (roughly 75% of cases) meaning that other colours can remain unaffected.

We hope this article has provided an interesting insight into how the human eye perceives colour. Here at Brightsea, we rely on being able to reproduce an excellent range of colours with exceptional accuracy for all of our print materials. If you would be interested in securing our Exeter printing services, why not fill out a contact form here. Or you can check out our latest blog posts on print and design by clicking here!