Hue, Saturation, Luminance (HSL) Color Model
Hue is the color (red, yellow, green, or blue) for the selected color, expressed as a value between 0 and 239. Saturation (Sat) is the strength or purity of color in a specified hue. This is related to the amount of gray in it and is measured from 0 (completely gray) up to a maximum of 240 (no gray). The higher the saturation, the purer or more vivid the color. Luminosity (Lum) is the intensity of lightness or darkness in a color, specified by a value between 0 (black) and 240 (white). If Saturation is 0, the Luminosity setting specifies a shade of gray.
Red, Green, Blue (RGB) Color Model
The RGB model, one of the Additive Color models, is used on computer monitors. It has three primary colors — red, green, and blue — that it creates by emitting light. These three colors are combined in various proportions to produce all the colors displayed on your screen. They are referred to as additive because they combine to produce white. Primary colors are measured as a value from 0-255. The colors produced by combining the three primaries are a result of the amount of each of those shades present. For example, pure red has a red value of 255, a green value of 0, and a blue value of 0. Yellow has a red value of 255, a green value of 255, and a blue value of 0. If Red, Green and Blue are set to zero, the color is black; if all three are 255, they produce white.