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
Today’s comparison group is exclusively curved ultra-wide monitors, most of which are intended for gaming. But the LG 38UC99 and Dell U3818DW are marketed as professional screens. Acer’s Z301C, Asus’ XG35V, and AOC’s AG352UCG are clearly for enthusiasts and gamers, as they include adaptive sync and feature high refresh rates. All are suitable for workday tasks however, and deliver good color accuracy. And as it turns out, three are VA panels and three use IPS parts.
The contrast divide is quite apparent here, as the three VA screens all top 2000:1. The Acer wins the day with nearly 3000:1 contrast. The Z38c lags hereslightly, but is on par with the other two IPS screens. There is a caveat here however: To get perfect grayscale tracking with the HP screen, we had to turn the contrast slider down quite a bit. That has a negative effect on dynamic range, to the point where a compromise was necessary to maintain image quality. This issue will have a greater impact on users engaged in graphics and video work. For things like spreadsheets and word processing, the HP delivers a clear image with plenty of brightness and detail.
Uncalibrated – Minimum Backlight Level
The backlight’s minimum setting gets fairly dark, at just under 40 nits. The brightness slider offers fine control, so achieving a precise level is easy. For 50 nits output, set the control to 14, with contrast at 67. Contrast remains consistent throughout the luminance range.
After Calibration to 200cd/m2
Here’s where the compromise happened during our calibration. To achieve perfect grayscale, the contrast control had to be set on 63. This makes it impossible to hit 200 nits output, which is our equalization factor. Raising the value to 67 got us to the right brightness point, with grayscale errors still well-below the visible threshold. We don’t consider this a major issue, it just requires balanced adjustments to find the Z38c’s full performance potential. And it is clearly not alone in having relatively low calibrated contrast. The Dell isn’t much better. If you don’t mind a slightly blue color temperature, the sRGB and Rec.709 modes are over 900:1.
ANSI Contrast Ratio
We saw consistent results when measuring an ANSI checkerboard pattern. To see a value higher than the sequential number is always a good thing. While this particular IPS part is a bit lacking in dynamic range, it is a quality panel with solid uniformity and a properly-installed grid polarizer. Ideally, we’d like to see higher numbers in both contrast tests, but the HP Z38c is well-suited for its intended productivity purposes.
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