LG GL850 B and 10 Bit colour mode in Windows

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  • #36298

    Vincent
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    Hi Vincent

    I am sorry to ask but how do I do a green primary measurement?

    Several ways:

    -spotread on an RGB 0,255,0 patch on paint
    -uncalibrated screen report should measure it
    -measurement report with a patch set with 0,255,0
    -HCFR
    … etcetera

    #36299

    Vincent
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    Also. In novideo_sRGB, should I enable ‘calibrate gamma to sRGB’?

    Thank you.

    it depends on your desired behavior for non color managed (games, CAD/CAM). Usually you want 2.2 non color manafed instead od sRGB on these low contrast displays.
    For color managfed apps it does not matter as long as display profile in OS stores the actual gamma, becaue it will be undone to content TRC & colorspace.

    #36311

    Raj S
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    No, that is a mistake. Those corrections differ on main green wavelength. 98% P3 aims for an AdobeRGB natuve grene primary, Macbook Retuna P3 aims for a exactly green P3 primary and 95% aims for a crippled green primary on intersection between 2D plot of P3 & AdoberGB, thus being the smallest colorspace of teh three.

    SPD can vary with these PFS phosphor displays. The blue peak could be taller, the green peak could also be taller. I meant to suggest that if you have a PFS phosphor display and the white point seems off (too warm, too red) with the 94% correction then try the 98% correction instead.

    But 94% should be fine for the user.

    Also. In novideo_sRGB, should I enable ‘calibrate gamma to sRGB’?

    Use Gamma 2.2 (relative) instead of sRGB. It’s actually a little bit misleading because sRGB boosts the blacks which is not what we want for accuracy.

    #36312

    mat a
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    I have calibrated my monitor following the info previously supplied (used the 98% correction), gamma 2.2, matrix+single curve (though the 98% correction says spectral)..

    I loaded sRGB as default profile in OS then plug my DisplayCAL profile in novideo_srgb tool.

    If I do not check the ‘calibrate gamma to sRGB’ (see picture attached), the picture is very red. Gey looks reddish. If I do the picture looks nice though no idea if it looks correct.

    It really is a nightmare trying to get a monitor calibrated to sRGB lol It is a very humbling experience. I have been working as a 3D Visualiser for 15 years and into pcs for 25+ years but DisplayCAL and calibration still eludes me!! 🙂

    PS: Vincent. I have done an uncalibrated screen report but it makes no sense to me.

    Thank you both for your help.

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    #36314

    Raj S
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    If I do not check the ‘calibrate gamma to sRGB’ (see picture attached), the picture is very red. Gey looks reddish. If I do the picture looks nice though no idea if it looks correct.

    Did you adjust the Color Temperature/RGB Balance on your display? I think what’s happening is that your monitor’s RGB is configured to be quite warm. When you tick the “calibrate gamma” box, it activates the correction and adjusts the color temp (so it’s not red anymore).

    To fix this, make sure you use the “Interactive display adjustment” in DisplayCAL when calibrating for the first time. It will help you set your monitor’s RGB balance to best match 6500K. The closer your monitor is to the target, the better it is.

    Also in the Novideo_sRGB, make sure “Calibrate gamma to” is set to “Relative” with “2.2” gamma and “100%” black output offset.

    I have calibrated my monitor following the info previously supplied (used the 98% correction)

    You might wanna use the 94% correction. I didn’t mean to confuse you or provide misleading advice so sorry for that.

    • This reply was modified 1 month, 4 weeks ago by Raj S.
    #36317

    Vincent
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    I have calibrated my monitor following the info previously supplied (used the 98% correction),

    And its wrong since yiour display has no AdobeRGB green… although is your i1d3 were extremely well behaved and close to std obs there will be no difference between all PFS phosphor corrections but there is not way that HP Z24x G2 correction will perfom BETTER. NO WAY.

    gamma 2.2, matrix+single curve (though the 98% correction says spectral)..

    You are mixing differet concepts. They are different things. Matrix is profile type, not cortrection.

    I loaded sRGB as default profile in OS then plug my DisplayCAL profile in novideo_srgb tool.

    If I do not check the ‘calibrate gamma to sRGB’ (see picture attached), the picture is very red. Gey looks reddish. If I do the picture looks nice though no idea if it looks correct.

    It should not unless novideo_srgb’s label ‘calibrate gamma to sRGB’ is doing what it is not supposed to (off => compute -lut-matrix-lut with VCGT data to ICC TRC, on => compute -lut-matrix-lut with VCGT data to sRGB TRC).
    Ask LeDoge. If “off” button is nit behaving that way, IMHO label name should be changed.

    #36318

    Vincent
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    Oh wait… LG says is a Nano IPS. I overlooked that info & scrolled down to P3 coverage.
    It’s a weird & cheap way to  emulate QLED spectral power distrubution using a film absortion layer over cheap LED backlight.
    On that situation correction is QLED, like with a  Samsung TV, bundled, because that is what film cover emulates.
    Depening on green main wavelegth a QLED may cover different green primaries as WLED PFS (there is little difference between them here, they are different in red).

    #36324

    Raj S
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    I had no idea Nano IPS = Quantum Dot. Seems like you’re right Vincent:

    “LCD Quantum Dot LED” should be the right correction

    #36325

    mat a
    Participant
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    Thanks all.

    I will try again! 🙂

    #36328

    Vincent
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    Thanks all.

    I will try again! 🙂

    Please notice that this may change whitepoint and only that. Whatever novideo_sRGB controls are doing won’t change, so ypu’ll need tio contact LeDoge and ask about what that param does.

    Also it’s easier to test DWMLUT with a LUT3D just to check that profile simulation will work as expected. Novideo_sRGB is a simplification running in nvidia driver or dedicated lut-matrix-lut HW in GPU.
    Or even easier, test your custom display profile. Once it’s ok you can start blaming other 3rd party configuration options but without verifying white& grey range on profile (numerically & visually non color managed)… all other things will be useless.

    • This reply was modified 1 month, 4 weeks ago by Vincent.
    #36331

    S Simeonov
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    Is that right for AW3420DW too? “LCD Quantum Dot LED” correction?

    • This reply was modified 1 month, 3 weeks ago by S Simeonov.
    #36338

    mat a
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    I have calibrated the monitor using gamma 2.2, 6500k white point (adjusted using my monitor RGB controls) and created a single cure + matrix. OS uses sRGB default.

    I used the ‘Quantum…’ correction.

    I plugged the profile into novideo_sRGB, check ‘calibrate gamma’ to 2.2 (relative), 100% black offset and the picture looks good to me. I do not know how to check it against sRGB in DisplayCAL.

    If I do not enable the ‘calibrate gamma’ checkbox in nvideo_sRGB it looks like the calibration does not take effect (or that my correction is so subtle as to not be noticeable).

    I am very hesitant to make you and Raj spend more time helping me because you have already been very helpful.

    I will try and ask ledoge about what ‘calibrate gamma’ does.

    Thanks

    • This reply was modified 1 month, 3 weeks ago by mat a.
    • This reply was modified 1 month, 3 weeks ago by mat a.
    #36341

    Vincent
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    Is that right for AW3420DW too? “LCD Quantum Dot LED” correction?

    No, it may be labeled nano ips but its SPD is WLED PFS. Check community database.

    You cannot trust manufacturer so we need to rely on independent reviews or community SPD. Same applies to

    #36342

    Vincent
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    Also we may have saved a lot of time it “mat a” had checked community corrections: 27GL850.

    It may be labeled nano ips by manufacturer… but it is not, it’s a WLED PFS, cheap version.
    https://colorimetercorrections.displaycal.net/

    Hence use one of the native gamut CCSS made by community for that display or use bundled WLED PFS 95% P3 correction.

    • This reply was modified 1 month, 3 weeks ago by Vincent.
    #36345

    mat a
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    I can assure you that I would have if I had known where to look. I am learning how to use the site and DisplayCAL.

    Will use the appropriate correction.

    Thank you

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