For designers and professional photographers it’s often important to maintain consistent colour rendition from the camera, through to the computer display used for browsing and editing photos and right through to the final output device, generally a printer. Colour management tools use software ‘profiles’ and hardware monitor calibration and printer calibration devices to try to ensure this consistency of colour. It’s a complex process, and it’s worth pointing out that when images are going to be displayed on a screen rather than being printed, you have no control over the colour rendition of the output device. Many photographers don’t use colour management at all.