This perspective diagram graphically illustrates the three dimensions of color used by the Munsell Color Chart for color measurement and notation.
The first dimension is HUE, measured on the band or equator shown in perspective as encircling the central pole. This is divided into ten equidistant Hues arranged in the order of the spectrum:
Red, Yellow-Red, Yellow, Green-Yellow, Green, Blue-Green, Blue, Purple-Blue, Purple, Red-Purple. Five simple Hues and one compound Hue are printed in the diagram as they appear at these points. The other compound Hues are designated by letters only:
G-Y, P-B, R-P, Y-R.
In the second dimension of his color wheel, Munsell defines VALUE. It is measured on the central pole which is gray and neutral to all the Hues. This pole is divided into regular steps from dark to light. This dimension shows how light or dark a color may be.
The third dimension on this Munsell Colour Wheel is CHROMA, measured on the paths (shown in perspective) running from the neutral pole out to the equator or beyond it. This dimension measures the weakness or strength of a color. The Chroma scales of RED and its opposite Hue, BLUE-GREEN, are shown here at middle Value, from neutral out to the maximum strength of each. It will be noted that RED is twice as strong as BLUE-GREEN.
The Chroma paths of the other Hues are indicated in outline only. Each
of these paths may be drawn from any other step on the Value scale. Yellow, for example, which is weak at middle Value, can only attain its maximum strength at a higher step.
The dimension of Hue is expressed by a word or the initial letters of the word:
GREEN, YELLOW-RED, etc., or G, Y-R, etc.
The dimension of VALUE is expressed by the number of the step upon the Value scale, written over a line thus:
The dimension of CHROMA is expressed by the number of the step on the Chroma scale, written below the line thus:
For example, the color at the extreme right of the diagram is Red, Value 5, Chroma 10 and is expressed as: