Apple Color 1.0 - Manual (Page 158)

158 Chapter 8 Video Scopes
In this way, every color that can be represented in Color can be assigned a point in
three dimensions using hue, saturation, and lightness to define each axis of space.
The sides of the cube represent color of 100-percent saturation, while the center
diagonal from the black to white corners represents 0-percent saturation. Darker colors
fall closer to the black corner of the cube, while lighter colors fall closer to the
diagonally opposing white corner of the cube.
HSL
The HSL (Hue, Saturation, and Luminance) color space distributes a graph of points
within a two-pointed cone that represents the range of color that can be displayed.
 Absolute black and white lie at two opposing points at the top and bottom of the
shape.
 The primary and secondary colors are distributed around the familiar color wheel,
with 100 percent saturation represented by the outer edge of the shape, and 0
percent saturation represented at the center.