RGB colour model is a colour that is based on light. These three colours are the three primary colours with green replacing the colour yellow. When the three colours are combined, then it becomes possible to produce any other colour. This colour model is only used with source of light and does not apply to printing (Albers 2006).
CMYK colour model is the colour method that is based on pigments. The initials stand for Cyan, Magenta, Yellow, and Black. K stands for black. When the four colours are used, it becomes possible to achieve other colours. CMYK model cannot reproduce the same amount of colour as the RGB colour model. This is the reason why when printed yellow-green at times appears slightly muddy. This is the method employed by printers the world over. It is also an intelligent way or mixing paints (Albers 2006).
Colour space is a helpful conceptual tool for comprehending the capabilities of colour of a digital file or device. Thus, when one is trying to make a reproduction of colour on another device, the colour spaces reveal whether one will manage to retain the highlight or shadow detail, the saturation of colour as well as, by how much wither of the two will be compromised.
The process of keeping colour consistency in digital photography runs from the minute one takes a photo, uploads it to the computer, converting the same to jpegs and printing it using a variety of output technology. The process of editing an image involves the existing profile of the image. This is what is referred to as a working colour space.