Page:Atlas of the Munsell color system.djvu/9

 CHART

CHART H. INDEX FOR COLOR NOTATION.

This chart suggests all color paths and records each step by a simple NOTATION. The ten steps of hue are written RP (red-purple), P (purple), PB (purple-blue), B (blue), BG (blue-green), G (green), GY (gr'een-yellow), Y (yellow), YR (yellow-red or orange), and R (red).

Initials at the top of the chart trace the Sequence of Hues; numerals at the side trace the Sequence of Values and the small numeral printed on each color step is an index of its Chroma i,e. strength or saturation. The color step made of vermilion bears the chroma numeral 10; it is at the value level 4:- and in the red column R. This step is written 5R $4⁄10$ - as explained in a previous introduction and in chapter VI of "A Color Notation. "

If this chart were bent around the equator of the color sphere forming a cylindrical envelope, it would imitate a mercator chart of the globe, each hue taking the place of a meridian and each value level representing a parallel of latitude, while the chroma numerals would correspond to altitudes.

Were this cylinder cut open on the red-purple meridian (RP) it would spread out to form this Hue Chart;- green being at its center with yellow and red (warm hues) to the right, and the cool hues blue and purple to the left.

Colors shown on this chart form the irregular outside of the color tree, between which and the neutral gray trunk are the intermediate degrees of weaker chroma, which appear on the succeeding charts R. Y. G. B. P and 20. 30. 40. 50. 60. 70. 80. of the system.

AVOID DUST, HANDLING AND EXPOSURE TO STRONG LIGHT.