Munsell color system

In colorimetry[?], the Munsell color system is a color system that specifies colors based on three color dimensions. It is very similar in concept to HSV, but includes a series of books containing standard color swatches, similar to Pantone.

Henry Munsell, an artist, wanted to create a "rational way to describe color" that would use decimal notation instead of color names (which he felt were "foolish" and "misleading"). He first started work on the system in 1898 and published it in full form in Color Notation in 1905. The newer Munsell Book of Colors continues to be used today.

The system consists of a sphere with the value axis (light/dark) running up and down through it, as does the axis of the earth. Dark colors were at the bottom of the tree and light at the top, measured from 1 (dark) to 10 (light).

Each "slice" of the sphere across the axis is a color wheel, which he divided into five basic colors, red, yellow, green, blue, and purple, five intermediates, yellow-red, green-yellow, blue-green, purple-blue, and red-purple. Hues were specified by selecting one of these ten basic colors, and then referring to the angle inside them from 1 to 10.

Chroma, known as saturation in the HSV system, was measured out from the middle of the wheel, with smaller values being less saturated (washed out). However in this regard the Munsell system leaves some to be desired, because different hues have maximum saturation at different points. For instance yellow colors have considerably more powerful saturation than greens, due to the nature of the eye. This led to a wide range of possible chroma values, and a chroma of 10 may or may not be saturated depending on the hue and value.

A complete color was specified by listing the three numbers. For instance a fully saturated blue of medium brightness would be 5B 5/10 with 5B meaning the color in the middle of the blue hue band, 5 meaning medium brightness, and 10 being fully saturated.