This happens in digital photography each color is represented by three numbers (which indicate the proportions of red, green and blue in the RGB system) which are the primary colors, mixing them we get all the others. Each monitor or printer has its own set of colors (or gamut color space which is decribed by the corresponding color profile) that can reproduce, and any color of a set is represented by three different numbers in each set.
In order to represent the colors of an image are created different color spaces, all subsets of the eye, then smaller, that are associated with cameras, digital scanners, or that are associated with the images "raw" from programs editing such as, for example, photoshop. Even monitors have their own color space that is the set of all the colors that the display can show and the color profile is a table that describes it.
