HLS Color Spaces
HLS color spaces are also widely used by artists. Its color components are hue, lightness, and saturation.
Hue has the same meaning as the HSV model, except that a hue angle of 0° corresponds to blue in this model. Magenta is at 60°, red is at 120°. As with the HSV model, complementary colors are 180° apart.
Lightness is the amount of black or white in a color. Increasing lightness adds white to the hue. Decreasing lightness adds black to the hue.
Saturation in the HLS model is a measure of the "purity" of a hue. As saturation is decreased, the hue becomes more gray. A saturation value of zero results in a grayscale value.
The following figure is a line drawing of HLS space, which is a double hexcone. Any horizontal cross section of the HLS color space is a hexagon. HLS is a normalized color space. That is, the lightness and saturation values range from 0.0 to 1.0 inclusive. Hue varies from 0° to 360° inclusive.
HLS color spaces can be device dependent or device independent.
CMY and CMYK Color Spaces
The CMY and CMYK color spaces are often used in color printing. A CMY color space uses cyan, magenta, and yellow (CMY) as its primary colors. Red, green, and blue are the secondary colors.
The following figures are color representations of the CMY color space. The CMY color space is normalized.
The CMY color space is subtractive. Therefore, white is at (0.0, 0.0, 0.0) and black is at (1.0, 1.0, 1.0). If you start with white and subtract no colors, you get white. If you start with white and subtract all colors equally, you get black.
The CMYK color space is a variation on the CMY model. It adds black (Cyan, Magenta, Yellow, and blacK). The CMYK color space closes the gap between theory and practice. In theory, the extra black component is not needed. However, experience with various types of inks and papers has shown that when equal components of cyan, magenta, and yellow inks are mixed, the result is usually a dark brown, not black. Adding black ink to the mix solves this problem.
The CMY and CMYK colors spaces can be device independent, but most often they are used in reference to a specific device.
| 
