LG 34UM67 sRGB Data and Bench Tests

For color accuracy, we test before and after calibration. For calibration, we use SpectraCal CalMAN with our own custom workflow. We target 200 cd/m2 of light output with a gamma of 2.2 and the sRGB color gamut, which corresponds to a general real-world use case. We use an i1 Pro provided by X-Rite. All measurements use APL 50% patterns except for uniformity testing, which uses full field.

LG 34UM67 Pre/Post Calibration
Pre-Calibration,
200 cd/m2
Post-Calibration,
200 cd/m2
Post-Calibration,
80 cd/m2
White Level ( cd/m2) 201 198.7 79.3
Black Level ( cd/m2) 0.2056 .2153 .0977
Contrast Ratio 978:1 923:1 811:1
Gamma (Average) 2.18 2.21 2.21
Color Temperature 6558K 6548K 6482K
Grayscale dE2000 2.94 0.38 0.99
Color Checker dE2000 2.49 1.24 1.39
Saturations dE2000 2.14 1.07 1.17

Before calibration, the LG 34UM67 has a slight blue tint to the grayscale but nothing too noticeable – especially for gaming purposes. Tweaking the OSD settings to 53/50/47 RGB gives a result reasonably close to the ideal 6504K color target. The grayscale errors are all under 4.0 dE2000, which is potentially visible but not overly so, with an average error level of 2.9 dE2000. The gamma curve isn’t great, starting high and ending low but with an average of 2.18 that’s close to our 2.2 target, so things can definitely be improved. Moving to colors, there are a few larger errors of nearly 5.0, mostly in the yellows and oranges. Some of these are due to the gamut falling slightly higher than sRGB, leading to some oversaturation of green and red.

Post-calibration the gamma and RGB balance are almost perfect. The average grayscale dE2000 falls to well below 1.0, which is invisible to the naked eye. Colorchecker and saturation accuracy improves as well, though there are still colors in the 4.0 range. Again, it’s mostly shades of yellows, oranges, and some greens that cause problems, which unfortunately tend to be the worst colors to have wrong for imaging professionals. Overall it’s a good monitor, and the target audience clearly isn’t going to be imaging professionals, so with or without calibration it will do well for gaming, movie watching, and other general tasks.

Changing to 80 cd/m2, the calibration results remain pretty consistent. The dE2000 numbers are slightly higher, but if the small change in accuracy is a concern then potential buyers would have already passed on this display. Only the most finicky of regular consumers might find something to complain about.

It’s also worth quickly discussing some of the other color modes, just because certain ones can be so far off that it’s a wonder anyone would even consider using them. LG offers four picture modes (Photo, Cinema, Reader 1, and Reader 2). Photos has a strong blue tint with average grayscale dE of 6.4 and many values nearing 10.0, though colors aren’t quite so bad averaging closer to 5.0. The Cinema mode is pretty close to the Custom setting, so while it’s tinted blue the grayscale dE is 2.3 while the colors average close to 4.0, with skin tones often falling into the 6.0+ range. Reader 1 and 2 are supposed to be more like print, with the results being heavily red biased with limited blue, and minimum black levels are much higher (2.5 cd/m2). The resulting grayscale dE2000 of 10.8/8.7 and average colors of 7.5/6.0 however are not particularly useful.

And that sums up why NVIDIA didn’t bother with supporting specialized color modes on their G-SYNC module: doing one color mode properly is generally more useful than supporting multiple incorrect color modes. While some people might appreciate the ability to quickly switch between various color modes, most just set up a display for everyday use and leave it be. Most named presets other than “standard” or “custom” end up being bullet points more than anything useful.

LG 34UM67 Brightness and Contrast LG 34UM67 Display Uniformity
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  • Crunchy005 - Wednesday, April 1, 2015 - link

    more unsupported rather than proprietary nature. Proprietary seems to get thrown around to much.
  • p1esk - Tuesday, March 31, 2015 - link

    Double the resolution, then get the price down to $499, and I will consider it.
  • wolrah - Tuesday, March 31, 2015 - link

    "the screen went black and never came back"

    *snicker*
  • Asmodian - Tuesday, March 31, 2015 - link

    Isn't FreeSync disabled when over the VRR? Your in game (F1) ghosting test is with FreeSync disabled. What is the ghosting like with FreeSync active? I understand overdrive is forced off whenever FreeSync is active.
  • JarredWalton - Tuesday, March 31, 2015 - link

    Behavior over the max VRR depends on the game setting -- it can be either VSYNC on (which will effectively cap FPS at max VRR) or VSYNC off. I personally leave it off, as I like being able to run at higher FPS.
  • Dribble - Tuesday, March 31, 2015 - link

    And his other point about ghosting - on other freesync monitors overdrive gets disabled when freesync is on, is that the case here?
  • JarredWalton - Wednesday, April 1, 2015 - link

    I took plenty of ghosting pictures to check this out as much as possible. From what I can see, overdrive ("Response Time" in the LG OSD) is fully active with or without FreeSync.
  • Soulwager - Tuesday, March 31, 2015 - link

    "AMD tells us that they drive a display at its max refresh rate when the frame rate drops below the cutoff"

    Could you test that? PCPer said the display was staying at it's MINIMUM refresh rate when your framerate drops below the cutoff.
  • JarredWalton - Tuesday, March 31, 2015 - link

    Sadly I don't have any equipment suitable for testing the actual refresh rate, which is why I say "claims". Right now, I'm pretty sure that if you fall below 48 FPS the display refreshes at 48Hz. I suspect it's something AMD can change with driver updates. We're still waiting of CrossFire FreeSync as well, so maybe the next driver update will alter the way this works.
  • dragonsqrrl - Tuesday, March 31, 2015 - link

    This is not a good variable refresh rate display, plain and simple. In fact I would argue it's not a good desktop monitor in general. I think the fact that this monitor even came to market illustrates the difference between Nvidia and AMD's strategy and design philosophy.

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