Brightness & Contrast
To read about our monitor tests in-depth, please check out Display Testing Explained: How We Test Monitors and TVs. Brightness and Contrast testing is covered on page two.
Uncalibrated – Maximum Backlight Level
The 32UD99 is the fourth HDR-capable monitor we’ve reviewed so far. Relating test results to picture quality at this point in time looks like a simple brightness and contrast equation. If a monitor can get very bright, and produce deep blacks, it will display HDR content at a higher quality level. Since LCD panels have relatively low contrast, a full-array backlight with zone dimming will produce the greatest dynamic range. So far, the only screen we’ve tested with that feature is the Dell UP2718Q. Today’s group also includes the Dell S2718D, which accepts HDR10 but does nothing to enhance the signal. Then we have BenQ’s EW277HDR, which is a step up from the Dell, offering a VA panel with 3000:1 contrast. Rounding out the comparisons are the SDR-only Acer BM320 (IPS) and AOC U3277PWQU (VA).
We’re showing the HDR luminance results here for both our review subject and the reference-level Dell UP2718Q. The Dell is one of the few 1000-nit panels currently available, and it topped 1100cd/m2 in our tests. The LG 32UD99, by comparison, offers over 560nits in HDR mode, which is respectable. It won’t deliver a VA panel’s deep blacks, but it does have the highest native contrast we’ve ever seen from an IPS part, over 1400:1 in SDR and over 2000:1 in HDR mode. The latter employs a bit of dynamic enhancement to up the number, but manages good HDR quality with no clipping of detail.
Uncalibrated – Minimum Backlight Level
Taking the backlight to its zero setting produces 36.5822cd/m2, a little darker than we prefer. To set 50cd/m2, we moved the slider up four clicks. Black levels are superior to the other IPS panels here, and any similar screen we’ve tested for that matter. While not quite in the league of VA panels, this is a major step forward for IPS technology. Contrast remains consistent at 1441.6:1 in SDR mode. We recommend leaving the backlight maxed for HDR content. Otherwise, it looks no better than the standard fare.
After Calibration to 200cd/m2
Our calibration, which as we noted earlier was unnecessary, did not affect contrast at all. It remains solidly over 1400:1, which is excellent for an IPS display. Only VA screens can boast superior performance in this test. And you can see that without the zone dimming available in HDR mode, Dell’s UP2718Q is the same as a typical IPS monitor.
ANSI Contrast Ratio
ANSI contrast numbers are nearly the same whether viewing SDR or HDR on the LG 32UD99. This suggests that a checkerboard pattern may not the be the best way to measure HDR contrast. Several new patterns have been suggested by industry professionals, but none have been decided upon. For now, we’ll stick to sequential contrast as a measure of a panel’s HDR capability. In the LG 32UD99’s case, its HDR image depth is a little better than BenQ’s, and slightly inferior to Dell’s. Given the price points at work here, that seems appropriate.
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