Contrast ratio values are based on maximum monitor brightness, which differs from one screen to the next, and is unusable for most of the time when it is at its maximum. There is thus no point in comparing monitors' contrast ratios. A screen that registers 800: 1 will not necessarily be any better than one that is "half as strongly contrasted" at only 400: 1. The first screen will probably be brighter, which is only an advantage if the screen is to be installed in a public place where it needs to be extremely bright so as to be visible to everyone, and from a distance.
To get a realistic idea of the actual quality of a monitor, the contrast ratios need to be tested using the same value for white for all of them (such as 110 cd/sq.m, for example). This would mean that the contrast levels will be much more representative of the range of graphic options of which the screens are capable, and especially their ability to render really dark blacks.
Of course, there is little chance that most manufacturers will introduce such a measurement themselves, although top-tier manufacturers might. They could introduce this new data while retaining another measurement at maximum brightness, if required.
In other words, ISO must take the initiative. The ISO 13406-2 norm is used to define a large number of standards applied to LCD screens, including those to be found at involving dead pixels (see the previous article ), response time and contrast ratios. We are aware that the standard is currently being revised and updated. We look forward to seeing the result.