The HSV color space
The HSV color space defines color in degrees of Hue, Saturation and Value and is closely aligned to the RGB color space.
Hue is traditionally a number between 0 and 360, mimicking the degrees around a circle with Red as 0, Green:120 and Blue:240. The intermediate compound colors are Yellow:60, Cyan:180,and Magenta 300.
Saturation defines the degree to which one or two of the primary colors are present and is a value between 0% and 100%
Value is also a number between 0% and 100% which represents the darkness of the color and is the percentage of the primary color in the mix.
In the following animation of a "color cone", the Hue is presented as colors around the cone, with the highest Value at the broad end, with the Value decreasing towards the point, where the colors all tend towards black.
The base of the cone displays the familiar color wheel, where the hues are displayed around the circumference and the Saturation is displayed with the most highly saturated at the rim, decreasing towards the centre where all the colors tend towards white.
