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Brightness & Contrast
To read about our monitor tests in-depth, please check out Display Testing Explained: How We Test Monitors and TVs. We cover Brightness and Contrast testing on page two.
Uncalibrated – Maximum Backlight Level
We’ve tested a few HDR monitors featuring peak brightness of 400-1,000 nits. At the top of the price ladder (about $1,800 each) sit the Asus ROG Swift PG27UQ and Acer Predator X27. Both exceed 1,000 nits and feature 384-zone full array backlights. Also packing that 1,000 nits spec is the Philips 436M6 Momentum, although it makes do with an edge array backlight in contrast to its expensive competitors. 400-nit screens are represented by the LG 34GK950F and LG 27UK850. All but the latter include extended color gamuts.
When the XB273K senses an SDR signal, it allows the user to choose between having the variable backlight on or off. Turning it on doesn’t really affect the peak brightness, which is around 440 nits. That is more than enough brightness for even the most severely sunlit rooms. The “Peak White” (aka brightness) slider is reasonably accurate and very precise, so you can dial back to a more-comfortable 200 nits brightness with ease.
The variable backlight really improves the black level, taking the screen into VA panel territory. You can see the difference in the second chart. It takes the measurement to just 0.0954 nit, which is very dark, indeed.
Resulting contrast is an impressive 4,614.4:1—achieved without any clipping of highlight or shadow detail. This is a dynamic contrast feature that can be used for all content without penalty.
We recommend leaving the variable backlight on all the time.
After Calibration to 200 nits
The variable backlight effect is less pronounced when the backlight is set to 200 nits brightness. White levels are visibly a tiny bit brighter, and black levels typically come across twice as dark. This returns a still very respectable 2,173.1:1 contrast ratio. While many VA screens can boast better numbers, the XB273K beats the other IPS monitors here with more than double the dynamic range.
ANSI contrast is not affected by the variable backlight when measuring a static pattern (our pattern averages 50 percent brightness). Contrast appears greater when there is a greater proportion of white on the screen, like when editing a spreadsheet or using a web browser. Gaming is similarly affected. Bright scenes have more depth than dark ones. As far as IPS monitors go, the XB273K offers an average intra-image contrast ratio.
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