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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  • FXi - Monday, May 25, 2015 - link

    It would have been helpful to list in the article what the "consistent" constrast ratio was. I'd be guessing it was more likt 750/800:1 given IPS performance in the past but while low and high are very useful, knowing where someone will likely land being somewhere in the middle of the road would be useful to readers. Only making a suggestion. I am always grateful for the things you DO include in your reviews and I read them pretty through and through.
  • KarenS - Friday, July 24, 2015 - link

    There are no VESA mounting holes on this monitor. Could you verify that you reviewed the correct one? I bought a "34UM67" and did not find any VESA mounting holes. The pictures on your site shows no mounting holes either.
  • Jiffybag - Sunday, October 11, 2015 - link

    How did he flatten the game curve when the monitor has no gamma controls? I bought this monitor and my gamma looks exactly like his pre calibration gamma image (starting high ending low) but as thre is NO way to calibrate gamma (only colour / white balance) I was unable to correct it? Anyone care to explain? Jarred?
  • Jiffybag - Sunday, October 11, 2015 - link

    Game = gamma (auto correct got me) :)

    My settings:
    Backlight set to 20 (120cd/m2)
    Black adjuster set to 0
    Using i1Display Pro
    Power savings etc all turned off
    Colour calibration is good (all under delta 1.6)
    Colour temp is spot on 6500k
    Grey scale delta error all less than 1
    Gamma set to "1" in menu

    Gamma average is 2.2 BUT it's a diagonal line \ starting high (at 2.4) and ending at 1.9.
    As there is no 10point gamma control I am unable to figure out how to flatten the gamma as there is no gamma controls? My HDTV has 10pt gamma control so I can raise 10/20/30 and lower 70/80/90 to flatten a curve, but this monitor has absolutely NO (ZERO) gamma controls so how on earth can he flatten it to such a decent flat line? I'm baffled? Unless he used the dynamic contrast adjuster (black level adjuster) and/or used his GFX card to make adjustments to his output, I'm unsure how he was able to do this. I'd love to know though if anyone can enlighten me :)
  • Jiffybag - Sunday, October 11, 2015 - link

    I have a 34UM67 and it has VESA mounting holes, but no gamma correction control? :-/
  • rya - Monday, October 19, 2015 - link

    has anyone tried overclocking this monitor or altering the freesync range? I'd love to run freesync from 9hz - 80hz (or higher) if possible.

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