Grayscale Tracking & Gamma Response
Our grayscale and gamma tests are described in detail here.
Racing mode is the MG28UQ’s default preset and in this case it runs a little cool. All brightness levels from 20 percent on up show a slight bluish green cast. Colorwise, the image lacks a bit of red. For those who don’t choose to calibrate their monitors, there is a better preset shown below.
sRGB is the best out-of-box picture mode. Its only real flaw is that you can’t adjust brightness or contrast once you’ve selected it. Output is locked at 170cd/m2 which is a very usable level. The only grayscale errors show up at 70 percent where you’ll start to see a subtle purple tint. In most content this won’t be a problem. Objects like clouds or ice might show it but only barely.
The User mode allows access to an adjustable white point preset. That gave us decent results especially in the middle and upper tones. There aren’t any errors visible here at all. To get the 100 percent target below 2dE, we had to lower contrast a little, but we think the additional accuracy is worth it.
Now we’ll look at all the monitors.
It seems that two of the three TN panels show visible grayscale errors in their default states. While the problems are only just over the threshold, there is better accuracy to be found in some of the more expensive products. We’d happily use any of the top four screens without calibration.
Our adjustments take the MG28UQ to a good level of accuracy. All of the monitors perform well after adjustment; the top three particularly so. It’s pretty hard to find a bad display these days. Even the value models offer at least one accurate picture mode or the ability to calibrate to a high standard.
There are no gamma controls on the MG28UQ, so you have to accept what’s provided. The default Racing and sRGB modes come fairly close to 2.2 but are slightly above the line, which means they’re a tad dark. The luminance errors are small but if there were a 2.1 or 2.0 gamma preset, the picture would pop a little more. The best way to deal with a gamma curve like this is to increase the backlight a click or two; perhaps to 210 or 220cd/m2.
Even after calibration, gamma tracking is nearly unchanged. We thought tweaking the Contrast setting might flatten the trace more but it didn’t. We are picking nits here but again, a little brighter gamma would be an improvement.
Here is our comparison group again.
Tracking is quite good when compared to the other screens. Some of them have visible spikes or dips in their charts. Only the U2879VF can truly be called flat. A .21 variation in values is small though.
We calculate gamma deviation by expressing the difference from 2.2 as a percentage.
The MG28UQ’s 5 percent deviation results from an average value of 2.31. Here’s another scenario where IPS seems to be the better tech. Remember that all three TN panels come from AU Optronics. They are made from the same part as every other 28-inch Ultra HD monitor on the market. Their similar gamma performance is therefore no surprise.