In our biz, colour accuracy can make or break a project. As a one-off, it may not seem that important, but when you’re printing hundreds or thousands of something, it’s crucial that colours match not only each other, but also with the company’s branding.
Colour is tricky though because each person perceives and interprets colour differently. So, what is colour, and with so much up for interpretation, how can anyone trust their own colour perception? Good question.
What is colour?
Let’s start from the beginning. Colour is the visual perceptual property in humans to different wavelengths of electromagnetic radiation between 390 nm to 700 nm – what’s known as ‘visible light’. This visible light excites three different types of receptors (or cones) in our eyes that our brains interpret as colour. Because we have three different receptors, humans are trichromats. It’s estimated humans can distinguish up to 10 million variations in colour.
Fact: Domesticated dogs are dichromatic, meaning they only have two different colour receptors.
What variables affect our perception of colour?
One of the most important factors in colour perception is the light with which an object is viewed. There are several different reasons for this:
Our eyes are amazing at compensating for variations in our environment. When viewing something in a reddish or blue light, our brain will compensate for this different light source after a short while, and we will perceive that light as ‘white’. That said, the exposure to this light will affect our perception of colour. Check out the photo below for example. The second card is the exact same colour in both frames, but because of the overall cast we perceive the top one to be much more pink.
Both sunlight and fluorescent lighting appear white, even though they have very different spectral distributions. This is due to our trichromatic receptors. Even though light may be composed of different spectra, if it creates the same response in our eyes it will be perceived as the same colour. Two different spectra that are perceived the same are called metamers.
Tip: This is why colours should always be viewed in controlled lighting. Colours may match perfectly under one light source, and not at all under another.
The cones that sense colour only function when there is a sufficient source of light. When light levels are low, a different receptor in the eye takes over: rods. Rods are responsible for our night vision, but are only sensitive to one wavelength. This is why our night vision is monochromatic. This shift from utilizing cones to rods happens gradually, so if you are viewing colour in dim light, you may not even realize that your colour perception is compromised.
You’ve heard the saying “beauty is in the eye of the beholder”? The same can be applied to colour. Each person perceives colour a little differently. If you’ve ever had one of those “pink vs red” debates you know what I’m talking about. And, not only do we each perceive colour differently, gender and culture play a role in our perception of colour, too!
Most of the genes responsible for colour vision are on the X chromosome, making colour acuity a gender-linked trait. As much as 8% of men suffer from some sort of colour blindness, with red-green distinction being the most common (sorry guys). Conversely, 2-3% of women have a 4th colour cone and can be considered tetrachromats. Freaks.
Want to see how you rate for colour acuity? Try this online colour challenge.
Believe it or not, perception of colour is also influenced by the psychology of the observer. Studies find that both culture and language affect our perception of colour. For more on this, check out “Do You See What I See?”, a BBC special on the subjectivity of colour perception.
Bonus: For some fun colour-testing fun, check out this pacman illusion.
Interested in learning how printer colour management works? Find out here!