Munsell colour tree, 1970-1971.
© Science Museum / Science & Society Picture Library
The Munsell colour tree is a three-dimensional scheme representing colours using hue, brightnes and saturation. The American painter Albert Henry Munsell (1858-1918) first devised this system of parameters back in 1913. In this model colour samples are mounted radially on vertical semicircular plastic plates. These show changes in colour hue around the circular axis, while colour saturation increases outwards, and brightnes from top to bottom.