Results: Grayscale Tracking And Gamma Response
The majority of monitors, especially newer models, display excellent grayscale tracking (even at stock settings). It’s important that the color of white be consistently neutral at all light levels from darkest to brightest. Grayscale performance impacts color accuracy with regard to the secondary colors: cyan, magenta, and yellow. Since computer monitors typically have no color or tint adjustment, accurate grayscale is key.
The Q2963PM’s out-of-box grayscale rides a little blue at the default Warm color temp preset. This option is closer to the correct 6500K than the other presets, but represents an average Delta E error of 4.24. Since a Delta E value of three crosses the visible threshold, we're getting a little blue tint to white content (a tint that increases with the brightness level).
Fortunately, this is easily fixed in the User color temp mode.
This is an excellent measurement run, except for the 100 percent signal level, which is still too blue. You can fix this by lowering the Contrast control, though you drop the max luminance level below 200 cd/m2 in the process. Practically, the error is almost never visible because real content rarely reaches a full 100 percent output level. You might see the blue tint if you watch a hockey game, for example, but we couldn’t see any problem in either productivity or gaming applications.
You can see that neither a monitor’s resolution, nor its price tag affects its grayscale performance.
The AOC’s stock grayscale error, while not overly grievous, is below average compared to the majority of other monitors. This is the only metric that comes up a little short, in our opinion.
But let’s see how things stack up after calibration:
Don’t let this chart fool you into thinking the AOC is a poor performer. An average Delta E error of 1.19 is still quite imperceptible. And this number is affected by the 100 percent measurement. The rest of the luminance range is nearly perfect. In fact, if the 100 percent value were removed, the Q2963PM’s average would be .83 Delta E, tying with ViewSonic's VX2770Smh.
Gamma is the measurement of luminance levels at every step in the brightness range from 0 to 100 percent. This is important because poor gamma can either crush detail at various points or wash it out, making the entire picture appear flat and dull. Correct gamma produces a more three-dimensional image, with a greater sense of depth and realism. Meanwhile, incorrect gamma can negatively affect image quality, even in monitors with high contrast ratios.
In the gamma charts below, the yellow line represents 2.2, which is the most widely accepted standard for television, film, and computer graphics production. The closer the white measurement trace comes to 2.2, the better.
The last AOC screen we reviewed, the I2757FH, also showed excellent gamma response. We are glad to see AOC’s attention to detail on this very important metric. The Q2963PM showed only tiny bumps at 20, 80, and 90 percent. When the trace is above the yellow line, it means that the signal level is too dark (around seven percent too dark in this case).
Here are the gamma numbers put up against the same group of monitors.
With a span of only .21, the AOC is looks pretty good, and is only outdistanced by two much more expensive QHD screens. This means its gamma response is fairly flat from the darkest to lightest signals.
We calculate gamma deviation by simply expressing the difference from 2.2 as a percentage.
The I2757FH we tested back in January is still the only display to measure a perfect 2.2 for average gamma. The Q2963PM is only slightly behind at two percent. Any display that comes within 10 percent of the standard is showing solid gamma performance.