The RGB color model is the standard model for additive color mixing used for color displays on screens. It is based on the absorption maxima of the visual pigments of the human eye and is used for emitting color displays.
The RGB color model is based on the three primary colorsred, green and blue and offers the most extensive color space that can be realized with three colors. It applies to normal RGB and to standard RGB( sRGB). More colors can be represented with this color model than with the CMY color model; however, it cannot represent all colors occurring in nature.
The RGB color model can be represented as a cube in which the vertices represent the saturated primary colors red, green and blue, the saturated secondary colors cyan, magenta and yellow, and the achromatic colors white and black. The edge lengths of the RGB color model are formed by vectors of length "1".
Thus white, consisting of the color vectors of red, green and blue, has the value 1, 1, 1. If one assigns 8 bits to the vectors of the primary colors, then each primary color can assume 256 saturation values. This means that a total of 16.7 million different colors can be defined from three primary colors, each with 256 saturation values.
There are several color models and techniques with which the RGB color space can be extended. These include Red, Green, Blue, White( RGBW), Red, Green, Blue, Yellow( RGBY) and Red, Green, Blue, Cyan, Yellow( RGBCY) whose color space covers almost all colors found in nature and the backlighting in monitors.