Understanding Colour: From the Munsell System to Colour Perception

Colour can seem endlessly complex, but one of the most useful systems for understanding it, for me has always been the Munsell Colour System. Developed by Albert H. Munsell in the early 1900s, it breaks colour down into three measurable dimensions: Hue, Value, and Chroma.

The Munsell System

• Hue refers to the basic family of colour - red, blue, yellow, green, and so on - and how they transition around the colour wheel.

• Value describes how light or dark a colour is, ranging from pure black (0) to pure white (10).

• Chroma measures a colour’s intensity or saturation - how vivid or muted it appears.

These three axes - hue, value and chroma - form a model of colour. I find this really useful when painting, because it helps separate lightness from saturation and hue. You can shift a colour’s value without changing its chroma, or make it duller without changing its lightness. This mental model helps enormously when trying to match colours from life or from a reference.

How We Perceive Colour: Everything Is Relative

We perceive tonal value (how light or dark something is on a greyscale) and colours based on what is around them. In other words, everything is relative!

When I first saw these illustrations it really helped me guard against these biases when trying to evaluate tonal values and colours when painting.

I don't know about you, but when I see illustration 1 above, it looks like both the larger rectangle and the smaller rectangle turn gradually from dark to light, and light to dark. This isn't the case!

In illustration 2 above, I just turned the larger rectangle into a black block and did nothing to the smaller rectangle. With illustration 1 my brain was making me think that the small rectangle was graded from dark to light because of what was behind it when in fact it was one block of unchanging grey... I was fooled!

A similar thing happens to me when I look at illustration A and B. When I look at A, the small square looks lime green to me. When I look at B however, I perceive the smaller square in the middle to be more orangy. When I join these smaller squares together however, as seen in image 4, I can see that they're exactly the same colour! I'm just perceiving them as different because of the colour that is behind them.

Watch out for these illusions when painting or drawing from life, they're everywhere. Sometimes there might be parts of your painting (as happens to me often) where you can't quite tell which colour is wrong and it could well be because of this illusion. A good way around this is by looking at the colour or value you're trying to replicate on your canvas through a small hole cut into some black paper, so all you see is a colour and no other colours around it.

Next time you’re painting or drawing, try thinking about colour in terms of hue, value, and chroma and notice how your perception changes when you isolate a colour from its surroundings. It’s amazing how often our eyes play tricks on us. Have you spotted this kind of illusion in your own work? I’d love to hear how you deal with it so leave a comment below or send me a message.