PA271Q target white point error

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  • #15944

    AlexK
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    After trying three copies of Benq SW271 and reading on the topic (thanks for all the helpful threads on this forum, too!), I gave up on 4k and got a NEC PA271Q with Spectraview II.

    I’ve calibrated the monitor with Spectraview II (D65, 2.2, 120 cd/m) and profiled it with DisplayCAL (WLEDFamily_07Feb11.ccss, Large Testchart for LUT profiles). The results of the verification test are better than anything I’ve managed to achieve so far with Benq, factory calibration of NEC, and calibration-only of NEC, but the target whitepoint is still off by dE >2 (report attached).

    I see the assumed whitepoint is 6700K and the measured one is 6654K. Where does DisplayCAL gets the assumed whitepoint from? I disabled all settings on the calibration tab to “as measured” and disabled interactive display adjustment. Anything I’m doing wrong?

    Grayscale is the main noticeable and measurable (by displayCAL validation) difference between system ICC profile generated by SpectraviewII and DisplayCAL (switching system ICC profile using macOS display preferences).

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    #15954

    Vincent
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    PA271Q is not a “WLED” is a “WLED PFS phosphor” (graphic arts variant).
    “WLEDFamily_07Feb11.c css” is meant for WLED sRGB displays like common office WLED monitors or laptops.

    You can use as correction:

    -the ones used by Spectraview II (in Spectraview II instalation folder, like “NEC_64_690E_PA242W_2013-02-28.edr” which is GB-LED sample). They are not W-LED PFS samples… but since SVII works with them you can check if that app did its job with accuracy.

    -WLED PFS for P3 displays (Panasonic VVX17P051J00) but this is meant for iMacs and multimedoa P3 displays. It’s almost the same as yours but green is different

    -WLED PFS for graphis arts display (HP_DreamColor_Z24x_NewPanel.edr). You can get this from HP Z32x software or Lightspace corrections or wait till NEC add them to Spectraview.

    EDRs can be translated to CCSS text files with ArgyllCMS tool “oeminst”.
    IMHO you should:
    -play the game with the same rules as SVII (use NEC corrections even if they do not match exactly your monitor backlight)
    or
    -use the most accurate one (the one from HP)

    If you own a very accurate  i1 DisplayPro, which strores in its firmware sensivity curves and they are very close to standard CIE observer 2º, it won’t matter which correction you use, corrections will “correct less”.

    Assumed whitepoint is closest white in daylight curve (100K multiples) to measured white.
    Low dE to assumed white means that measured white is a daylight white (curve of warm to cool whites in blue-yallow axis, b*), so you won’t percieve a pink or greenish tint (green-red axis, a*).

    Grayscale is superb : choose “RGB + gray balance” in drop menu in report. Individual dC are low and range a*b* is OK even validated agsinst a true neutral grey. That means that greys have the same color as white, so you should not worry.

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

    #15983

    AlexK
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    Thanks, Vincent. Using the converted “NEC_64_690E_PA242W_2 013-02-28.edr” correction I indeed got better results. The DisplayCAL’s validation of the SVII calibration now shows better results than the WLED correction I used before, and profiling further improved that as expected (attached). The ICC profile created by DislayCAL has deeper blacks and I prefer it over the ICC profile generated by the SVII during calibration.

    A bit surprised to see that NEC didn’t include correction for the new type of panel and while SVII claims it now supports PA271Q that support is apparently only limited to writing the calibration results. Anyway, that’s better than what I’ve got with BenQ and my concerns on the hardware issues are resolved.

    Thanks for the help.

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    #16043

    Vincent
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    Yes, it’s annoying that NEC has not updated their software (checked 1.1.39) even if all we know that it is a graphics art WLED PFS phosphor (like HP EDR), like for example:

    https://www.chiphell.com/thread-1950286-1-1.html
    WLED PFS phosphor graphic arts SPD

    Anyway, it you are happy with 1st option (validate with the same rules as SVII) and white point looks “white”, it’s OK.

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