Grayscale Tracking And Gamma Response
Our grayscale and gamma tests are described in detail here.
One might look at the default grayscale tracking chart and conclude the XB321HK is ready to go without adjustment. That is mostly true. Certainly in this test, there’s no concern. RGB levels are almost ruler-flat from bottom to top. This is the result we’d expect from a professional monitor.
Our contrast and gamma changes alter the landscape a little at the 100% brightness level. There we see a slight blue reduction on the chart, but the error is still below the visible point. Things are still looking quite good for our test subject.
Here is our comparison group.
The XB321HK would beat out most professional displays in the out-of-box grayscale test, yet there is no evidence of a factory-certified calibration here. Acer is simply using a good panel part that’s been engineered properly.
We don’t often record a worse grayscale result after calibration but .85dE is still a super-low error level. The change is due to the 100% brightness point which has shifted thanks to our gamma and contrast adjustments.
Now we get to the heart of the matter. This is what the XB321HK’s gamma looks like by default. You’d think some sort of dynamic contrast was at work here, but that is not the case. It’s simply a result of the contrast slider being set too high. In real-world content you’ll see a distinct lack of definition in brighter material and highlight detail will disappear.
After changing only the contrast slider, gamma greatly improves. At least now we’re getting close to the mark. It still looks a little too dark, however. We wish there were a 2.0 setting, but there isn’t.
We weren’t sure which chart we liked better, this one or the previous. To the eye, it’s a matter of preference. When gamma is set to 1.8, the image is a little brighter. One might leave it to personal preference, but after you see the color gamut results on the next page, the choice becomes clear.
Here is our comparison group again.
Tracking isn’t quite ruler-flat like the others, so the XB321HK finishes last in this test. A .5 range of values isn’t too bad but at this price point, it should be better.
We calculate gamma deviation by simply expressing the difference from 2.2 as a percentage.
Gamma is a compromise with the XB321HK, although the 1.8 setting is better for color accuracy as you’ll see on the next page. It also comes closer to the 2.2 standard. It seems four of the screens could use a tweak in this department. Only the XB271HK and XB2700-4K hit the mark squarely.