One of the frustrations of using a desktop scanner is that a scanned image can look different on screen than it does when printed, and both can vary quite a bit from the original. The solution to this problem is a colour calibration (or colour matching) system. Such software is really valuable only for scans of high-quality images (transparencies, professional-quality prints, etc.) that need to meet rigorous quality standards – for most people using a desktop scanner, accurate colour is not as important as fast, pleasing colour. This is just as well, as the complexities of colour and human perception have made calibration a daunting challenge – and as a consequence, there are several different solutions already available, with more on the way.
One of the most comprehensive systems is the Kodak Colour Management System (CMS), which uses its own colour definitions together with profiles for each different scanner, monitor, and printer in the system to translate and standardise colours. Elements of the Kodak system are bundled with Adobe PhotoShop and other software, and CMS is rapidly becoming the favourite of graphic artists and others who depend on closely matched colours.
Other systems have been developed by individual scanner manufacturers and software publishers. These proprietary profile-based systems can also do the job, provided that they include profiles for all of the different devices that will be used for scanning, viewing, editing, and outputting the final image.
A final approach is known as output-based correction, and involves scanning and outputting a standard calibration target, and then making adjustments to colour profiles in order to standardise colours. This is a less sophisticated process, and is probably inappropriate for users who want to continually re-calibrate their systems for optimum results. For basic colour scanning, however, output-based correction is often sufficient