Grayscale, Gamma & Color
Our grayscale and gamma tests are described in detail here.
None of the 38UC99’s image modes stray too far from D65, but the closest one is Custom, which happens to be the default setting. If you don’t plan to calibrate, we suggest using that preset for both gaming and productivity. It runs a tiny bit green at 90% and 100%, but you’d be hard-pressed to see the issue.
FPS Game 1 also measures pretty close to the mark and doesn’t look that different from Custom. It just makes a slight tweak to gamma and color. It also locks out all adjustments except brightness so you can’t dial it in to taste. Only Custom offers that flexibility.
After working the RGB sliders a bit, we achieved near perfect tracking. The 38UC99 comes with a factory-certified calibration but only for grayscale and gamma. While it matches the enclosed data sheet closely, there is just a bit more quality left for tweakers like us to find. This is seriously excellent performance.
As impressive as the 38UC99’s before-and-after results are, they aren’t enough to take the win in this group of premium screens. But LG can still be proud that its 34UC98 wears the crown here. Seriously though, there is nothing to complain about in either chart except for AOC’s out-of-box number. And that is easily repaired with a few changes to the OSD. These monitors may be expensive, but they deliver performance commensurate with their price-tags.
There is very little to be said about the 38UC99’s gamma performance other than that it’s awesome. Even the FPS Game 1 mode barely changes the tracking. There, a little more emphasis is placed on highlight and shadow detail, but it’s barely visible. Calibration doesn’t affect the result at all either. It can’t get much better than this.
A .04 range of values is about as tight as it gets for any display. In fact, only one monitor has scored better in this test with a .03 result — that would be BenQ’s PV3200PT professional video editing display. In the LG monitor's case, it helps boost perceived contrast a little and adds some additional depth to the image. Though it only achieved an average result in our contrast tests, its super accurate gamma helped make it look much better than the numbers suggest. With an average value of 2.17, the top three monitors (including our review subject) are only 1.36% off the standard.
Color Gamut & Luminance
For details on our color gamut testing and volume calculations, please click here.
LG didn’t include color gamut measurements in its calibration data sheet, but it might as well have. The out-of-box charts are excellent. Aside from slight over-saturation in the two highest red points, every measurement is on target. Luminance levels are ideally balanced as well. Blue has been pumped up slightly to compensate for the tiniest under-saturation. And red does the opposite, dropping its brightness just a little to make up for being over-saturated. Resulting average error levels are extremely low. Out of the box, the average is 1.34dE. FPS Game 1 mode returns 1.68dE and the calibrated result is .90dE. The 38UC99 offers all the quality and accuracy of the best professional monitors we’ve tested.
With our minor adjustments in place, the 38UC99 takes the color accuracy crown, narrowly edging its 34UC98 stablemate. There’s no reason this monitor can’t be used as a proofing tool provided you don't need the wider Adobe RGB color gamut. To that end, it covers sRGB with a little bonus red taking total volume up over 104%. This likely represents the best gamut performance possible from an IPS panel with a white LED backlight.