To test HDR-capable monitors, we follow a similar procedure to our benchmarks for color, grayscale and gamma.
CalMAN has a special workflow designed for HDR10 displays that measures grayscale in 5% brightness increments, the EOTF curve and color saturation tracking for the DCI-P3 color gamut.
Grayscale accuracy for HDR and SDR is measured the same way. 6500 Kelvins is the standard for both signal types, and our test determines how close a monitor comes to that color temperature at all brightness levels. Above, you can see the errors both in the RGB chart and the Delta E graph. Any brightness level above 3dE has a visible error.
EOTF is the HDR version of gamma, and like that metric, it measures the amount of light at each brightness level and plots it on a curve. In our chart, the yellow line represents the standard, and the white trace is our measurement. You can see that the line takes a sharp bend at around the 75% mark. This the point where the monitor takes overtone mapping from the HDR signal’s metadata. That data tells the monitor what luminance level to assign to each brightness step. Ideally, the white and yellow lines should be the same. The example above is a nearly perfect measurement run. If the white line is below the yellow, that means the light level is darker than spec.
In the gamut chart, we measure color saturation and hue for all primary and secondary colors at 20, 40, 60, 80 and 100% levels. The goal is simply to put the dot inside the target box. HDR monitors should cover the DCI-P3 spec, so we measure against that standard.
We hope this gives you a clear understanding of our testing methods and why the results are important.
Which tests have more meaning will depend on your particular application. For gamers, contrast and panel speed are likely to be the deciding factors in a purchase decision rather than color accuracy. If you’re a photographer, color accuracy and gamut volume will matter more than input lag or viewing angles. For more help making your decision, read our our PC monitor buying guide.
As always if you have questions, please let us know in the comments section.