The Munsell Color Tree

One of the first attempts to specify reflective colors, color mixing and saturation was accomplished by Munsell (1903). He devised a color system based on factors he called hue, chroma and value. Munsell set up a three-dimensional arrangement based upon mintmum perceptual color 

Munsell set up a cylinder whose vertical axis began with black and ended with white . This is the factor Value in Munsell notation, each layer of which is given a specific number. He also defined five (5) primary hues. These are purple, red, yellow, green and blue. TTiey are arremged around a circle as shown in the following, and a series of circles are stacked to form a tree , namely  

In Munsell s system, hues are specified in a circular fashion with the same set of hues on the same level. As the value, i.e.- lightness , changes, one Jumps to the next highest circle. The amount of color deepness is specified as chroma and becomes less as one approaches the edge of each color circle. 

The advantage of this SYSTEM is that in addition to being able to specify hue, we can also specify Chroma, which is the degree of saturation of a specific hue, as we move from the center outwards. Value is the relative 

On a practical basis, if we wish to set up this S5 tem, we would assemble a set of color-chips at each point on the Color-Tree. Eaeh eolor-chip would be specified by two faetors, H = hue, and V/C, which is value (grayness) modified by chroma (saturation). The actual number of layers in the Munsell Color Tree was determined by minimum perceptual difference . That is, the minimum change in eolor that produces a perceptible difference. This arrangement specifies aU light colors as well as the dark ones. To use such a system, one would ehoose the eolor-chip closest to the hue and saturation of the test eolor and thus obtain values for H and V/C. 

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Once this fact was rccdized, it was understood that an average of what each person saw would have to be made if a standard system weis to be formed and promulgated. This led to the concept of the "Standard Observer". Thus, the research required to define and measure color took a completely different path from the original methods such as the Munsell Color Tree. 

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