Page:Atlas of the Munsell color system.djvu/21

 CHART

BLUE AND YELLOW-RED CHART.

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

VALUES of blue and yellow-red 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 $B 4⁄6$ is cobalt, the strongest permanent blue, which exhibits 60% of chromatic strength and reflects 40% of the incident light. Its opposite $YR 4⁄5$ reflects the same percentage of light but only 50% of chroma. To balance this pair the areas must be inversely as the chroma, i. e., since the yellow-red exhibits one sixth less strength than the blue, six parts of the yellow-red will balance five parts of blue. Attention to these measures leads to pleasing combinations.

Any chosen steps of blue and yellow-red upon this chart may be balanced by noting their symbols:- thus light yellow-red ($YR 6⁄8$) balances dark blue (B|4|5), when the areas are inversely as the product of the symbols viz:- twenty parts of light yellow-red ("orange") and forty-eight parts of dark blue.

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.