It is difficult to describe colors in such a way, that each apparatus (digital camera, scanner, LCD screen, printer) reproduces colors correct. Ever had a print with disappointing colors? Then you already experienced that transferring color information between different devices is not as easy and straightforward as you would like it to be.
Cameras describe colors as a mixture of red, green and blue (RGB). The amount of each color is described by a number. The number combination (0,0,255) equals a dark, saturated blue color and (128,128,128) represents middle gray. Just like with people, each apparatus registers a color just a little bit different than another apparatus. One camera will describe a specific color as (100, 240, 100), whereas another camera will describe exactly the same color as (0, 237, 40).