Page:Atlas of the Munsell color system.djvu/23



CHART

PURPLE AND GREEN-YELLOW CHART.

This chart presents a vertical plane passed through the axis of the color solid and bears the complementary hues, purple and green-yellow. This pair of opposite hues is shown in regular measured scales from black to white and from grayness to the strongest color made in stable pigment.

VALUES of purple and green-yellow range vertically from black (0) to white (10). CHROMAS or strengths of color range horizontally from neutral gray to the maximum (10).

Each step in these color scales bears an appropriate symbol describing its light and its strength. Thus $P 4⁄6$ is a compound purple, the strongest permanent color, which exhibits 60% of chromatic strength and reflects the same amount of light as N 4/ of the value scale. Its opposite $GY 4⁄5$ reflects the same amount of light but only 50% of chroma. To balance this pair the areas must be inversely as the chroma, i. e., since green-yellow is one-sixth less strong than the purple, six parts of green-yellow will balance five parts of the purple. Attention to these measures leads to pleasing combinations.

Any chosen steps of purple and green-yellow upon this chart may be balanced by noting their symbols, thus light green-yellow ($GY 8⁄6$) balances dark purple ($P 2⁄3$), when the areas are inversely as the product of the symbols, viz:-six parts of light green-yellow and forty-eight parts of dark purple.

Chapters III and IV of the handbook, "A Color Notation," describe these balances and their combinations with other hues. The symbol on each color step is its NAME, a measure of its light and strength by which it is to be memorized, written and reproduced.

AVOID DUST, HANDLING AND EXPOSURE TO STRONG LIGHT.