NCS, the Natural Colour System

The idea behind it

NCS builds on the opponent colour theory of Ewald Hering, who observed that red, yellow, green and blue each look pure, and that no colour looks both red and green or both yellow and blue. Swedish researchers turned this into a working system through large viewing experiments in the mid twentieth century, and it became a Swedish standard in 1979. A person needs no instruments or knowledge of pigments to use it. You judge a colour by eye: how blackish it is, how strong, and where its hue lies between two of the four pure hues.

Reading a code

A code such as S 2030-Y90R has two parts. The first four digits give the nuance: 20 per cent blackness and 30 per cent chromaticness, which means strength of colour. The rest, to make up 100, is whiteness, here 50 per cent. The second part gives the hue: Y90R means a yellow with 90 per cent redness, in other words a red with a touch of yellow. So this is a soft, light, slightly pinkish red. The S shows that the colour belongs to the current standard edition. Pure greys are written with N.

Where it is used

NCS is the reference standard for colour in Sweden, Norway, Spain and South Africa. Its atlas holds about two thousand colours. Architects favour it because the code itself tells you how the colour will look and how it relates to others: two colours with the same nuance but different hues feel like a family. Many European paint makers give NCS codes for their colours. Like any collection of printed samples, it is a commercial product, and the physical swatch, viewed in daylight, is the standard.

Sources and further reading

• Natural Color System on Wikipedia
• NCS Colour: The Natural Colour System
• Handprint: modern colour models