COLOR SOLID

A three-dimensional figure representing all degrees and combinations of hue, saturation, and brightness in the perception of color; also called the color cone, color pyramid, and color spindle. The color solid is an extension of the color circle to include the dimension of brightness. In the color circle all the hues in the spectrum (plus purple) are arranged around the circle according to wave length, and the degree of saturation or purity is indicated by distance from the center. The color solid adds a cone on the top side of the circle to show colors of increasing brightness, and another cone on the bottom side to represent colors of decreasing brightness. The distance from the basic circle shows the degree of brightness and darkness, with maximum brightness at the point of the top cone and maximum darkness at the peak of the bottom cone. The straight line between these two points, passing through the center of the circle, represents only varying degrees of brightness, that is, the black-white dimension, since hue and saturation are both lacking along this line. To picture the color solid more vividly, imagine a series of color circles of increasing size piled above and below the basic color circle. Starting from the basic circle itself, these layers become lighter and lighter as you go up and darker and darker as you go down. Hues toward the outer rim of each circle are richer (more saturated), while those toward the center are paler (less saturated). But note that the layers also become smaller and smaller as they get farther away from the basic circle. The reason is that the greatest range of saturation is found in colors of medium brightness—that is, the point where the color solid is widest—and the range of saturation decreases as the hues approach pure white and pure black. Color studies have shown that the color solid should not be perfectly symmetrical, since the relationships are not quite so uniform as it indicates—for example, a highly saturated yellow is much brighter than a well-saturated blue. Nevertheless every combination of hue, saturation, and brightness lies within its boundaries, and there is no better way to show the impressive array of colors that can be perceived by the human eye. If an accurate three-dimensional color solid were constructed, showing every gradation, it is estimated that the total number of distinguishable colors would come to no less than 7.5 million.