RGB Color Spaces
An RGB color space is created by mapping the colors red, green, and blue onto a 3-D Cartesian coordinate system. This results is a 3-D cube like the ones shown in the following figure. This figure displays the same RGB cube from two different angles. Notice that the origin of the coordinate system is black. This is where the red, green, and blue (RGB) color components are all 0.0. The diagonally opposite corner of the cube is white, where the RGB color components are at their maximum value.
Like most color spaces, the RGB color space is normalized. That is, all color values are restricted to the range of zero to one inclusive. So black is (0.0, 0.0, 0.0), and white is (1.0, 1.0, 1.0).
In the RGB color space, the primary colors are red, green, and blue. The secondary colors are cyan, yellow, and magenta.
RGB color spaces can be device dependent or device independent.
HSV Color Spaces
Hue, saturation, and value (HSV)color spaces are often used by artists. The hue is what we normally think of as color. Saturation is the amount of gray, white, or black that is mixed into the color. Zero saturation indicates no hue, just grayscale. The value component of the HSV space is a measure of its brightness. The HSV color space is normalized.
The preceding figure shows a line drawing of HSV space in the form of a hexcone. Each of its cross sections is a hexagon. At the vertices of each cross section are the colors red, yellow, green, cyan, blue, and magenta. A color in HSV space is specified by stating a hue angle, the saturation level, and the value level. A hue angle of zero is red. The hue angle increases in a counterclockwise direction. Complementary colors are 180° apart.
HSV color spaces can be device dependent or device independent.
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