T he Munsell Book of Color is arguably the first modern color model. It is based on the three attributes of color: Hue Saturation and Value, and was developed through careful color measurement. Conceived by the American artist Albert H. Munsell (1858-1918), it was described as a color order system in 1905 and published as an atlas of color samples in 1915. (This was republished in 1929 as the Munsell Book of Color.) The Munsell was extensively revised or “renotated” in the early 1940’s, when it was adopted as the standard color reference system in the USA. Munsell’s system is based on the 2D hue circle. Hue is the major organizing principal behind Munsell’s system. Hue was defined by Munsell as “the quality by which we distinguish one color from another.” He selected five principle colors: red yellow green blue purple and five intermediate colors: yellow-red green-yellow blue-green purple-blue red-purple While the selection of colors in our hue circle differ from Munsell’s, the same principals can be applied. Munsell’s sys- tem was created, in fact, to be infinitely expandable. Color Solids Munsell’s system is described as a color solid or a three dimensional color model. Many color theorists, scientists and artists have used three dimensional models in order to explain the dynamics of color. Three dimensional color solids such as these allow for the primary aspects of color (hue, value and saturation) to be illustrated in a sin- gle model rather than a series of unconnected charts. Munsell originally conceived of his color system as a sphere. The qualities of the hues in the Munsell system are very irregu- lar, however, and are best de- scribed visually by a solid such as the one shown to the right. This unusual shape has come to be known as the Munsell color tree. Three views of the Munsell Color Tree The Munsell color tree is organized by three fundamental aspects of color: Hue Hue is the purest form of a color. Hue is represented here as a ring. (Think of your hue circle) Value Value refers to the light or dark quality of a color. Value is rep- resented as a vertical axis with black at the bottom and white at the top. Saturation (Chroma) Saturation (called Chroma by Munsell) is the intensity or purity of a color. saturation is what dis- tinguishes a pure hue from a gray Tone Scale shade. VALUE The backbone of the Munsell system is a vertical value dimension, which represents equal steps of perceptual contrast from white to black. HUE Every Hue has a relative value. Some hues are light in value (like yellow) some are dark (like blue-violet). The fully saturated hue is located in a row next to it’s relative value. YELLOW BLUE VIOLET Saturation Saturation is measured horizon- tally, with the fully saturated col- or farthest away from the value axis. The distance between the hue and more saturated its relative value depends on the color’s intensity (or saturation). The goal is to achieve even per- less saturated ceptual steps of saturation from gray to the fully saturated hue. The steps of saturation should perceptually match those of the value scale. This is tricky since contrast of value and contrast of saturation are quite different The completed hue chart has the overall effect of even steps of contrast in horizontal, vertical and diagonal directions. The steps of value contrast are even and the steps of saturation contrast are even. Hues can have very different levels of saturation and also value (think of the value differ- ence between yellow and blue- violet.) As a result, some hue charts can have very different appearances. In the Munsell system, reds, blues, and purples tend to be stronger, more saturated hues. Yellows and greens are weaker and achieve their full satura- tion closer to the value axis. Complementary hues are ar- ranged across from each other in the Munsell tree.