The RGB color spaces is named according to the primary colors of the space: red, green and blue. Similarly, the CMYK color space uses cyan, magenta, yellow and black. These colors are added together to create values of the visual spectrum, as opposed to the CMYK space, where colors are taken away to reproduce colors.
Every color space is limited in some ways in terms of the colors it can reproduce, and the RGB color space is no different. The colors that the RGB color space includes are modeled as a Cartesian cube, usually running red along the X axis, green along the Y axis and blue along the Z axis. In this model, white and black run diagonally, from 0, 0, 0 to 1, 1, 1.
Electronic devices that handle graphic files tend to display and save files in the RGB color space. This includes the vast majority desktop scanners, digital cameras and computer programs on default settings. RGB files must be converted to CMYK ito print the colors in the file correctly, though much of the conversion is accomplished by automatic software processes in the printing device.
The colors produced by these color spaces are slightly different, though the RGB color space can reproduce a wider variety of colors. Most notably, RGB color spaces can display deeper reds, maroons, greens and blues. This leads to occasional misprints when directly printing an image in RGB format. For example, some of the RGB blues outside of the CMYK gamut appear more purple when printed. While this shift is observable, it is generally not noticeable in printing digital images.