LG 32EP950 (JOLED panel) and i1 Display Pro issues with Red

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  • #34068

    Raymond L
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    Hello! I was thinking about buying this monitor! Also own a i1displaypro so this post made me a bit hesitant..

    Did you work out the calibration issues? And how is the monitor behaving so far?

    The monitor itself is great. In my opinion, the last time I got this excited about display technology was years ago when IPS first became available in > 27 inches ( I didn’t find wide gamut pfs that amazing by comparison as that came between these two events).

    One thing I did learn is that targeting D65 white point with 1931 CIE 2 degree CMF simply does not work well – a bit yellowish/greenish. This is similar to the experience that Sony had with RGB OLED (e.g. https://pro.sony/s3/2021/01/22153606/ColourMatching_Between_OLED_and_CRT_E.pdf). I tried the Sony Judd hack and it works OK, but even better and cleaner is to target D65 with proposed CIE 2012 2 degree.  (Though in fact, the R/G/B OSD values only differ from the Judd hack by one click in Red.)

    This does mean you end up not taking full advantage of doing the calibrations in hardware unless you do something along the lines of the Judd hack in LG Calibration Studio (that does work).

    The good news is — I have done profiles with both LG and DisplayCAL using the i1 Display Pro, and despite the glitch, subsequent measurements using either a i1 Studio or SpyderX do not show a problem. Probably because the number of patches implicated in the profiles with problematic colors is too small to impact the matrix. (I did not experiment enough with 3D LUTs in hardware to express an opinion there.)  But as I prefer CIE 2012, I’ve settled on using DisplayCAL with i1 Studio as my production solution. In fact, the profiles with shaper+matrix in all my various whitepoint experiments differ only by small numbers (<=3) in the 3rd decimal place.

    The current theory from argyllcms mailing list is that it’s a i3 Display Pro/Plus v2 firmware incompat — but that’s a work in process.

    So I guess I am saying, I love it. Yea, it’s a bit inconvenient to use the slower i1 Studio path (it does not present problems with darker colors in my experience — the usual reason for preferring colorimetry)… and if you want to use LG Calibration Studio (to set the presets in hardware) with i1 Display Pro(or Plus), it’s OK but know that you will need to tweak your white point a bit.

    The studio professionals probably all use Calman, but at USD $2K for a Calman Studio license, I have not considered that path. Calman added support for this monitor in its recent update.

    i1Display Pro on Amazon   i1Studio on Amazon   SpyderX Pro on Amazon  
    Disclosure: As an Amazon Associate I earn from qualifying purchases.

    #34518

    Wisechoice
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    Hey there. I can strongly  recommend using LightIllusion’s ColourSpace with this display and a Blackmagic Micro Converter Bi-directional 12G as an external LUT box (using HDMI to HDMI). Especially since you have a spectro that you can use for probe matching. I started out using DisplayCal for calibration. Then I  bought CalMan Home for LG to use with my LG CX 48″ OLED. It was a nightmare trying to get a decent calibration. They refunded me, no questions asked, and I went with ColourSpace instead. I haven’t looked back since.

    Like you, I’ve also put my SypderX on the shelf and have been happy with an OEM version of the i1D3.

    Ted at displaycalibrations.com  offers fantastic support if you buy ColourSpace through him. He also made the discovery of that converter’s better-than-advertised LUT capability and has developed a way to detect and compensate for very subtle panel variance that can result in clipping, via analysis of RGB separation graphs in ColourSpace.

    I don’t have a spectro yet myself, but just last night, I was able to get average dE 2000 readings of 0.1376 (yes, you read that correctly) on a 1K point volumetric verification with the i1D3 (Wacom version).

    This solution allows you to affordably bypass the bare bones LG hardware calibration and problems like the one you had. You then get an extremely high caliber reference quality display for both SDR and HDR (although I haven’t calibrated for HDR yet, I’m told the performance is just as good). It will also allow you to harness both of your probes for fast and accurate calibration.

    Before profiling, I did a perceptual match with a calibrated Dell U2713HM (also calibrated using the BMD converter as LUT box) and measured that new white point on the JOLED. Then I created a custom colour space based on Rec709 with that measured white point, as a source for the creation of the 33-point LUT. The old LED backlights don’t suffer from the metamerism that newer OLED displays do, and can serve as a reliable reference if you don’t have a spectro. ColourSpace gives you the tools to do all this, and to check the results in a way that gives you full confidence in your display.

    The only warning I would give to anyone else reading this, who might be considering a purchase  of the 32EP950, is that LG displays are known to sometimes  suffer reliability issues. My own unit arrived virtually DOA from B&H. It worked for a few hours and then quit. But it was so beautiful while it lasted, that I knew I would never be able to go back to what I was using before lol. So I’ll likely purchase an extended warranty from them, although I don’t usually do that.

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    #34520

    Raymond L
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    Thanks for the tip.  If I find that I need something more, I will give a standalone LUT box a try. Honestly, as it stands now, calibration to get the RGB curves aligned (for good gray balance) and the desired white point dialed in is really all it takes.  I find that if I took the vcgt and grafted it over to a linear profile, the de00 barely budges rising from 0.22 to somewhere in the 0.5 range avg (the max for both were around the same 1.7).

    I did get the warranty from B&H 🙂 bec I’ve been burned for an unusually large number of premature display failures.

    I should re-iterate that when sticking with a curve+matrix profile, the failures seen with display pro don’t really change the overall characterization (it ends up being at most 2 patches out of several 100), but my initial alarm was due to not being sure that was the RCA instead of a faulty display.

    I actually have an update on the display pro issue bec I’ve managed to reproduce it with an iPhone 13 pro (!). It turns out to be orientation dependent. If the phone is sitting flat on the table, it measures a dark R=19,G=0,B=0 / 80 nits whitepoint patch ok, but if the phone is upright so colorimeter is in horizontal position, it fails.  This does not happen with an iPad Pro 12.9 (which is a pfs phosphor LED instead of an RGB OLED display). And I’ve even moved the phone way far away from my usual desk w/o any difference in behavior (bec one of the suspicions during the investigation with ArgyllCMS was electrical interference) and am attaching it.  It is 2 cycles each of measuring the 19-0-0 patch with phone flat then standing upright. Valid values when flat, zeroes (spotread timeout, cannot find edge) when standing upright.

    I shared it with Calibrite about 10 days ago, but I did mention that I’ve switched to a spectro so am not really awaiting a reply — they have not replied beyond saying it’s been passed onto x-rite. I cannot be sure if it’s just my unit or a more general issue and was actually hoping that maybe Calibrite can tell me (and swap the unit if it’s just mine, as it’s still under warranty).

    -Ray

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    #34522

    Wisechoice
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    Holy moly. Keep us posted as to whether they give you any response!

    #34976

    Blowi
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    My thought is that, the spectral sensitivity of i1diaplay pro is so weak around the wavelengths of the OLED red stimulus, so that when the brightness of “RED” is too low,  within  the integration time the colorimeter cannot gathers enough signal.

    That may also mean the sensitivity of  i1Display pro is not suitable to measure this type of display, or at least the R LED.  The XYZ tristimulus may have large errors if the spectrum of the R LED is too different from what the colorimeter is intended for (LCD with not-too-red red).

    #34978

    Raymond L
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    As to whether it’s the technology or the unit, without a 2nd unit to compare, the only people who can say are Calibrite or x-rite.  Unfortunately, they have not provided any updates, but to be fair, I did say that I’ve switched to using a spectro, which works fine and also supports using CIE 2012 2deg, which gives me what looks to be the correct whitepoint.

    What is fair to say is, while Calibrite has been friendly, if I were them, I would seek to resolve the issue and maybe offer to send a replacement unit. The unit is still technically under warranty. It is also evident from the interactions that all the actual R&D is done by x-rite, without any expertise at Calibrite. So, overall, I would say that my impressions of Calibrite have been lowered.

    Hopefully, this won’t apply to x-rite for its own products as I ended up upgrading to an x-rite i1Pro3.

    Strangely, while many say SpyderX is inferior, it works for me and the final numbers when measured with the i1Pro3 are only slightly worse than using the i1Pro3  (using 1931 model) — that could as easily be instrument agreement. The numbers were still well within acceptable ranges.  But rather than “hack” the whitepoint, I feel better getting it calculated with 2012 model, so felt the i1Pro3 was a worthwhile investment — esp as I negotiated a deal to receive the Publish upgrade included for an extra $80 — in case I want to do print profiling in the future.

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