Non-Western cultures may determine their color concepts by different means. Hue refers to the position in the spectrum of visible light. Each of the seven primary has a position on the spectrum measured in angstrom units.
Value represents the amount of light reflected, or the brightness of the color.
But, it must be noted that no true color has been found. White even has grays to black in it. There are no true orange or green, but a mixture of other colors. No color is pure, but an combination of other colors, although one particular hue is dominant. The body selects from sunlight whatever colors it needs to maintain balance, and these colors are absorbed by vibrations.