Measuring Color Gamut
Measuring the gamut is as simple as measuring what colors the monitor displays as pure red, pure green and pure blue. In other words, you get the coordinates of the vertices of the color gamut triangle. This information is written into an ICC file that can be used as the monitor’s profile by every application.
This solves the problem described at the end of the previous section: if the application knows the monitor’s color gamut and knows what gamut the given picture is optimized for, it can correct the picture in such a way that its colors looked like the author of the picture intended. If greens are stretched out on the extended-gamut monitor by 10% relative to the sRGB gamut, they must be shrunk by 10% when displaying an sRGB-optimized picture so that the colors looked like they should, i.e. without any tonal shift towards greens. This approach helps use the advantages of extended-gamut monitors for processing images and also work normally with ordinary sRGB-optimized pictures.
There are multiple difficulties, though. First, not all programs, even image-processing programs, can use data about the monitor’s color gamut. Of course, professional suites like Adobe Photoshop have no problems, but simpler programs, like image viewers, are deficient in this respect.
Second, the monitor’s profile alone is not enough. It is also necessary to know what color gamut the specific picture is optimized for to decide if it needs any correction. This technology exists in theory: JPEG and TIFF file formats can embed ICC profiles that report the native color gamut of the picture. However, most images do not have such a profile while most programs cannot use it.
Setting monitor profile in XnView manager
Well, some progress in this area could be observed recently. For example, Firefox 3.0, even though not a specialized program for viewing images, supports color management using ICC profiles. Many cameras allow not only embed a color profile into JPEG files but also save pictures in the AdobeRGB gamut that ensures a better reproduction of greens and is a better match for extended-gamut monitors. Cameras’ matrixes can make pictures with a large color gamut easily. Pictures are reduced to sRGB in them only for the sake of compatibility with sRGB monitors.
Setting color space on Canon EOS-350D
So, we are steadily progressing to problem-free operation of monitors with different color gamuts by means of ICC profiles. However, you need to be careful as yet when selecting and setting up the software you want to use with extended-gamut monitors if you want colors to display properly.