Acer XB280HK 4K G-SYNC Monitor Review

Acer XB280HK: sRGB Calibration and Bench Tests

Pre-calibration the Acer has a blue tint to the grayscale and a very strange bump past 95%. This kind of bump typically means that the contrast is set too high, causing the panel to run out of a particular color before others. In this case it seems to be running out of red and green, causing the blue levels to spike. The gamma keeps rising as well, causing the dE2000 values for the grayscale to reach 3.0 at points.

Colors are fairly well behaved, with the dE2000 values for the color checker staying below 3.0 for most of the range. They are very close to 3.0, so on static images you can tell the difference from accurate colors, but for non-professionals the display performs reasonably well.

For calibration, we use SpectraCal CalMAN 5.3.5 with our own custom workflow. We target 200 cd/m2 of light output with a gamma of 2.2 and the sRGB color gamut, which corresponds to a general real-world use case. The meters used are an i1Pro2 provided by X-Rite and a SpectraCal C6. All measurements use APL 50% patterns except for uniformity testing, which uses full field.

Post-calibration the RGB Balance and Gamma is almost perfect. The contrast ratio is only 736:1 but that isn’t much of a drop from the pre-calibration level of 769:1. Color errors are reduced, but as I’ll show here, that is only because the luminance levels are fixed. Unless a monitor has a 3D LUT, you cannot correct for over-saturation or tint errors in a display. Using an ICC profile and an ICC aware application you can fix some of those, but most applications are not ICC aware. Below you’ll see the color checker charts broken out into three different errors: Luminance, Color, and Hue. Color are Hue are what we cannot fix, while Luminance we can.

As we can see the DeltaL values are almost perfect now, but the DeltaC and DeltaH values are basically identical to before. Unless you have either ICC aware applications, or a monitor with a 3D LUT, this is all you’ll ever be able to do to correct a display. Grayscale and gamma improve, but a display needs to have accurate colors to be correct.

Targeting 80 cd/m2 now and the sRGB gamma curve we see similar results. The contrast ratio drops even more but that almost always happens. Colors have the same issues we’ve seen the whole time, with the DeltaL improving but not the Hue or Saturation.

Color accuracy on the Acer is okay but not fantastic. Since the pre-calibration numbers for colors are almost all below dE2000 levels of 3.0 most people will be fine with it. Many 4K displays to this point have had a focus on designers and photo editors, but the Acer is very much a gaming display, and in practice few gamers will really notice anything with the colors unless a display is really off, and that’s certainly not the case here.