Computational Colour Science Using MATLAB, 2nd Edition

Chapter 8

Colour Management

8.1 The Need for Colour Management

Colour images are displayed and captured using a wide variety of devices and technologies. Consider for a moment display devices that typically display images using three primaries known as RGB. At each pixel colour is represented by the intensities of the red (R), green (G) and blue (B) primaries. However, different display technologies use different RGB primaries so that, unless adjustment is made to the RGB values to compensate for these differences, the same image displayed on different display devices is likely to have a very different colour appearance. Even for a particular device, the colour appearance for a given RGB specification is likely to yield a different colour depending upon the settings of the device such as contrast, brightness, gamma and colour temperature¹. For image-capture devices such as cameras colour is represented by RGB values that represent the responses of three broadband colour filters. However, different manufacturers use different filters and, again, the settings of the camera (exposure time, white balance etc.) are likely to affect the values of RGB that are captured for a particular scene. It is clear that, without some process for compensating for these differences in device primaries and states, significant colour differences are likely to result between images of the same scene that are captured by various cameras and displayed on various devices (CRTs, LEDs, etc.) in various states. ...