The Munsell colour tree is a three-dimensional scheme representing colours using hue, brightness 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 brightness from top to bottom.
© Science Museum / Science & Society Picture Library