Brightness & Contrast
To read about our monitor tests in-depth, check out Display Testing Explained: How We Test Monitors and TVs. We cover brightness and contrast testing on page two.
Uncalibrated – Maximum Backlight Level
There are few monitors that perform in the PG27U’s class, but we picked a few HDR and high-contrast models for today’s comparisons. The HDR roster includes BenQ’s EX3501R, Samsung’s C49HG90 and LG’s 34WK650. The non-HDR squad consists of AOC’s AG322QCX and MSI’s Optix MAG24C, and both of these are VA-based with extended color gamuts.
We started our testing by measuring the PG27U with its Variable Backlight feature turned off. That showed us that the panel’s native performance is on par with a typical IPS part. It topped out at 310.6 nits with a reasonable 0.3 nit black level and a contrast ratio of 1062.8:1.
When we turned Variable Backlight on, black levels dipped to an extreme low of about .02 nits. We’re approaching plasma territory here. Meanwhile, the contrast ratio shot up to 17,131.3:1. Lest you think this meant sacrificing detail for clipping, fret not. Gamma tracked perfectly, and we didn’t lose detail in either shadow or highlight areas. This is the best SDR performance we’ve ever measured short of a plasma television.
Uncalibrated – Minimum Backlight Level
When the backlight slider is set to its minimum setting, the PG27U puts out a fairly impractical 23 nits. For a more-comfortable 50 nits, we recommend setting it to 11. Contrast remained consistent at 1,028.1:1. When we used Variable Backlight at this low brightness level, blacks were extremely deep.
The most the backlight can be reduced is to an extremely dim 23 nits. For a more useful 50 nits, we set the brightness control to 11, and contrast remained consistent at 1,028.1:1. When we used Variable Backlight at this low brightness level, blacks were extremely deep.
After Calibration to 200 nits
Calibrating to 200 nits of brightness did not hurt contrast. The PG27U still delivered a contrast ratio of 1,042.9:1 and a solid 0.2 nits black luminance.
HDR Brightness & Contrast
This is what we all came to see, and after taking our measurements, we couldn’t wait to publish the results.
The PG27U topped the Dell UP2817Q in HDR brightness with an impressive 1,156 nits. But look at the contrast result. Thanks to an amazingly low black level, we measured 61,843.6:1 contrast. To say that’s nuts would be an understatement. We reached this number by measuring a 10 percent window pattern, meaning the window takes up only 10 percent of the screen.
Upon measuring a full-field pattern, brightness dropped to 667 nits and contrast was 35,609.8:1. With any full-array panel, contrast is largely dependent on content and how well its local dimming control is implemented.
ANSI Contrast Ratio
We measured intra-image contrast in SDR mode. Turning on the Variable Backlight added nearly 60 percent to the result, a worthwhile gain.
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