Differences between calibration with Lg True Color Pro and Datacolor

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  • #35091

    Il Minu
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    Hi everyone, can anyone explain why when I perform a calibration with lg true color pro and then a validation everything seems to be ok, but when I check this icc profile with displaycal everything is completely off target? Am I doing something wrong or is there some other problem? I would like to point out that I use and have used Lg True Color Pro for hardware calibration, a feature that I find very useful.
    Thank you very much for your attention, I hope to solve my problem.

    P.s I have attached the 2 validations, the one with lg true color pro and the one made with displaycal.

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    #35095

    Vincent
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    1- Datacolor devices are not accurate devices, hence wahtever they measure is unlikely to be close to actual color coordinates. Get an i1DisplayPro

    2-Even with an i1DisplayPro HW calibration software from LG (TRue Color Pro) lacks of proper colorimeter corrections for most LG monitors (only sRGB and old widegamut GB-LED). Their software is sh*t and does not work properly.
    You’ll need to forge a proper correction into EDR used by LG TCP software (or LG Calibration Studio) in the same way Midas did in his thread about CS2731 calibration in this forum.

    3-Even if all were in place, you may to had used wrong correction in DisplayCAL, so if your spyderX was accurate (it is not) you may configured it (displayCAL ) in a wrong way.
    I say “MAY” because you selected White LED correction = LED sRGB displays. By your report that HW calibration looks like sRGB colorspace simulation BUT COLORIMETER CORRECTION NEEDS TO REFLECT NATIVE GAMUT TYPE (not your colospace simulation). It’s very likely that a current LG UHD HDR with HW calibration is 95% P3 diplay, which usually uses a “WLED PFS” type of LED… hence it is not  a plain White LED *if* my assumption of a P3 display is true. IDNK , put full model name. If it is a P3 display then DisplayCAL report has an user error by user misconfiguration.

    4- LG report show a bad grey, but it does not highlight the faults. Even using wrong colorimeter correction DIsplayCAL confirms it. Color casts in grey.
    That is another issue from HW calibration solutions from LG, Asus, Benq and in a lesser degree Dell & Viewesonic.
    LG panels bundled in those monitors are so bad behaved that their native behavior cannot be measured with just 10 measurements of each channel gamma ramp, hence a lot of greys errors go unnoticed and are not corrected (even if HW LUT could handle it). In a poor quaility panel you may need up to 48 measurements per channel and ArgyllCMS/DisplayCAL can do it for you.
    Check LeDoge’s DWMLUT or other tools from him to get HW-like smooth bandless calibration running on top of your GPU… sunce LG won’t correct thire cr*ppy software. They didn’t in a decade…

    TL;DR:
    -bad colorimeter, get an i1displaypro
    -bad monitor with bad HW calibration software => try Ledoge’s DWMLUT using DisplayCAL profiles.
    -possible user error by wrong choice of colorimeter correction in DisplayCAL, please write full model name.

    All three options can be true at the same time. The first 2 options are TRUE, no doubt about it.

    • This reply was modified 1 month, 1 week ago by Vincent.

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

    #35097

    Il Minu
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    Name of model: “LG27UL850”

    #35098

    Il Minu
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    Another calibration with only displaycal

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    #35101

    Vincent
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    Name of model: “LG27UL850”

    Looks like sRGB only, so your choice was  right (White LED) and my 3rd assumption wrong.

    Anyway, do not use fast calibration when buidong large XYZLUT profile, your display is not so good to be corrected with such smal number of uncalibrated gamma ramp measurements. At least medium. Grey grange in your last message seems not very good.

    Then read LeDoge’s DWMLUT documentation to load it as a LUT3D.
    A fast list of hints:
    -Create a DisplayCAL profile like you did, but better grey (slower)
    -Create a synth profile with your measured RGB primaries and desired gamma/TRC (if you aim to sRGB do not create it, it would be sRGB)
    -Create a LUT3D source profile => profile in 2nd step, destination profile => profile 1st step
    -Load it to DWMLUT
    -Assign as display profile the 2nd one  in OS configuration

    But if you are fine with DisplayCAL calibration (1D LUT grey calibration) and do not suffer banding… then skip that LUT3D step.

    #35103

    Vincent
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    Name of model: “LG27UL850”

    Name of model: “LG27UL850”

    Looks like sRGB only, so your choice was  right (White LED) and my 3rd assumption wrong.

    Also since it looks like a sRGB only display, LG software can measure it properly with an i1DisplayPro (White led OK, supported)
    Unfortunately grey range issues (a*b* errors in grey ramp) in your HW cal may not go away since it is 90% caused by too few measurements => use GPU 1D calibration or DWMLUT

    #35107

    Il Minu
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    Thank you very much for your advice. What do you recommend as the number of patches for profiling? P.s Sorry for the ignorance but is there a way to exploit the hardware calibration with displaycal? Or to load the profile directly into the monitor? In my case I mean

    #35108

    Vincent
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    Thank you very much for your advice. What do you recommend as the number of patches for profiling?

    What you used in your last profile. Just change calibration speed to medium or slow to ensure calibration takes betetr account of uncalibrated grey.

    P.s Sorry for the ignorance but is there a way to exploit the hardware calibration with displaycal? Or to load the profile directly into the monitor? In my case I mean

    No, you’ll need an SDK from monitor vendor to upload calibration to monitor. HP and Dell released an SDK for their monitors in the past with such funtionality for some models but newer versions of their SDKs have wipe out that functionality… monitor venders right now offer such SDK to paid software like Calman.
    Anyway, DWMLUT is visually equivalent to HW calibration and more configurable by far.

    #35109

    Il Minu
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    Okay, thank you

    #35110

    Il Minu
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    One last thing, (just to remove this doubt/curiosity) how come in the lg report everything looked more or less good, while in the displaycal report everything is off target? I mean, the results of the two tests are drastically different, are the values given in the lg tru color pro test perhaps false? Or is there some other reason that explains this huge difference?

    #35112

    Vincent
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    -LG is using custom correction for Spyder X, so whitepoint measurements are not accurate. Even if usiong built in correction it wont be accurate because SpyderX is not accurate. Also CCT is not a valid way to address whitepoint (LG report), it is only a coordinate, you’ll need two to get white color.
    (LG software may even be using proper built in White LED mode… but it fails to calibrate properly due the reasons explaines yesterday an another set of simplifications discussed in other threads about HW calibration in low cost monitors, like that software modifing OSD brightness after internal LUT is written).

    -LR report shows a very bad calibration of white, although it is not reported in the proper way. Just happens that it is not highlighting how bad it is although numbers are poor. “All green” => typical user won’t care to look at numbers. It is a markeing strategy, Dell & Benq do the same sh*t.

    -Your HW calibrations shows 2 main sources of error, a very bad grey calibration and a profile that does not match display near black. LG report did not measure those later zones.

    • This reply was modified 1 month, 1 week ago by Vincent.
    #35115

    Il Minu
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    I see, what do you think is a good monitor with Hw? Would the ViewSonic VP2768a-4K with calibration hardware be OK? Is it a good monitor?

    #35116

    Vincent
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    If the color uniformity of your current unit is good, use DWMLUT. That viewsonic will suffer from the same over simplifications (so if uncalibrated display is bad behaved…grey may be partially uncorrected). Also you’ll need an i1Displaypro.

    If you trully want a sRGB only with HW calibration check EA series from NEC, but software for HW cal has to be paid (Spectraview II , 100-150euro depening on store). In UHD model, EA271U, gamut is a littñe bigger in greens than sRGB and HW calibration is greyscale only (no gamut correction) but it has a sRGB mode with gamut limited to sRGB.

    I’ll try DWMLUT…

    • This reply was modified 1 month, 1 week ago by Vincent.
    • This reply was modified 1 month, 1 week ago by Vincent.
    #35119

    Il Minu
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    Can you explain to me in a very simple way what DWMLU is and how to use it?

    #35120

    Il Minu
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    I ran another calibration with lg true colour pro and a check with displaycal and the values are much better, is it due to the fact that during the calibration process with lg true colour pro I chose 3×3 matrix instead of lut table? Also, could you explain to me what the wording Measured vs. assumed target whitepoint weighted ΔC’00 is?

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