Which correction should I use to calibrate a GB-r led display?

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  • #32595

    tarna
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    Guys, I am really confused now with DisplayCal 3.8.9.3…. Previous versions worked okay. I have a Mac, with macOS Monterey now, and I’d like to calibrate my Asus ProArt PA279Q monitor, and it is impossible… I tried Auto (no correction), GB-r family, w-led family… The results are all heavily red when validating. gamut okay, brings the fabric data (99,9% srgb, 97% adobe-rgb, 1:1050 contrast), but the colors are all way out of good delta.
    Tried with g2.2, L* too. 160cd, 6500K, matrix based profile (LUT does not work under macOS). I have i1DisplayPro colorimeter, attached directly to the computer.
    If i calibrate with i1Profiler, everything is okay, works fine, with DisplayCal, just don’t know, ho to make it work… 🙁 (1-2 yeras ago it worked totally fine, but not now…)

    The attached file was the GB-r family corrected calibration result.

    Can you help me?

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    #32598

    Vincent
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    Dell_U2413_25Jul12.ccss (or the one you used) for i1 displaypro bundled with DisplayCAL. There is another EDR with a sligthly modified blue channel for GB-LED NEC PA242W, not bundled in DIsplayCAL but you can convert to CCSS using ArgyllCMS tools.

    CCSS Correction has nothing to do with a no pass calibration, that report shows that display is not well behaved and cannot be described with a simple matrix (primaries) + single TRC. Use a XYZLUT profile, which instead storing only rimaries will create a 3D mesh to map actual display response.

    Edit: also calibrated grey is bad, use slow speed in calibration.

    • This reply was modified 2 years, 5 months ago by Vincent.
    • This reply was modified 2 years, 5 months ago by Vincent.
    #32606

    tarna
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    Dear Vincent!

    I am not an expert that much with these expressions.. EDR, CCSS.
    As I wrote, under macOS the LUT table based calibration does not work, because macOS cannot handle LUT based icc profiles, only matrix based. The monitor did not behaved well…okay, what does it mean? 🙂 I see the wrong result, just don’t know what to do.  What changed in DisplayCal during the years? Two years ago there was no problem at all with this same monitor… And also, with iProfiler, no problem, matrix curve, same settings, validation okay.

    I made calibration for friends a few days ago with DisplayCal, under Windows, low-mid consumer range w-led monitors, Dell and Asus, srgb gamut, colors okay, green everything, but the contrast were around 1:800 both, even the febric sepc are 1:1000… Interesting.

    #32607

    Vincent
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    When you “Calibrate” you do 2 steps:

    1- calibrate grey, it’s the only you can do on a monitor without HW calibration & gamut emulation. This calibration is loaded into GPU. It ensures that grey color is as close as possible to 255 white of your choice, and that it has your desired TRC (“gamma”

    2- after calibration display is measured to make a profile, like a taylor measuring yur chest. Simple profiles (matrix) uses primaries corrdinates and assumes that your body will have the ideal proportions. Complex profiles masure your body with a 3D mesh.

    If after calibration a simple matrix profile cannot predict how display will behave (the shape of your body in taylor example) and you cannot use a 3D mesh… there is nothing you can do.

    Regarding “naming”:
    EDR=spectral correction (a spectral power distribution of WRGB channels, energy per wavelength of dispaly), binary format, Xrite IP
    CCSS= same as EDR but text
    Well behaved monitor=a monitor that behaves in away taht can be predicted with a matrix profile, a monitor that behaves almost like with ideal additivity of the 3 channels, so if you know “gamma” and primaries position you can calculate a RGB triplet for each CIE XYZ color that is inside monitor colorspace.
    Bad behavior in monitors can be preducted with a 3D mesh (ZXYLUT) that captures these irregulatites.

    #32625

    tarna
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    Dear Vincent,

    thank you for the really detailed answer! 🙂
    The only interesting thing now, why could I make calibration with previous DisplayCal versions, and why can’t now with the latest… Nothing changed at me – only the DC… 😉

    #32626

    Vincent
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    If you updated macOS you should update underlying ArgyllCMS. DisplayCAL is a frontend fro ArgyllCMS. Lastest argyll is 2.2.1 (intel x64, use rosetta if M1)

    https://www.argyllcms.com/downloadmac.html

    #32628

    tarna
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    It was a fresh install for ecerything, also just downloaded DisplayCal newly from here. Interesting, but fresh installed DC downloads Argyll 2.1.2  or so, not the latest you linked. Okay, I downloaded this latest Arg., recalibrated, medium speed, Auto corr., Dell U2413 corr. L*, G2.2., a few variations, but no change, same results. I don’t know, what’s happening, this program cannot measure GB-r led panels… I will try under Windows, in a few days, I have to install Windows back on a separetessd.

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    #32630

    Vincent
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    These errors are not related to DisplayCAL and panel type but to your low cost low quality display (cannot be mapped by a matrix accurately) or some issue in chain from macOS GPU driver – mac GPU output (when profilling or when measuring)

    • This reply was modified 2 years, 5 months ago by Vincent.
    #32632

    tarna
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    I think Asus Pro Art wide gamut 98% AdobeRGB monitor is not really low cost cheap display But okay. I will use iProfiler for my i1Display Pro, that works flawless.

    Thank you for the answers!

    Best regards, ZoltĂĄn

    #32633

    Vincent
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    Gamut  =/= quality or price

    EDR correction for GB-LEDs in i1Profiler is RG_phosphor (maybe they relabeled it to GB-LED). It stores 3 non GB-LED sample and one last sample wich is U2413 spectral sample. On a well behaved i1d3 (colorimeter, not monitor) this should not drift white point significatively.

    #32940

    Nicola
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    If it’s the display‘s fault and it can’t be calibrated with a matrix, wouldn’t i1Profiler also fail to calibrate it in the same way?

    #32941

    Vincent
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    If it’s the display‘s fault and it can’t be calibrated with a matrix,

    Profiled, not calibrated = behavior described by a matrix and 1 TRC or 3 TRC

    Calibration using these app is limited to grayscale.

    wouldn’t i1Profiler also fail to calibrate it in the same way?

    Yes.

    i1Profiler like DisplayCAL has 2 types of profiles, the simper ones (1TRC +matrx)  and the detailed ones (“table”, 3TRC + sometning akin to DIsplayCAL XYZLUT).

    If a display is bad behaved cannot be described by a matrix profile with superb accuracy, no matter the tool because boundaries or inner 3D colorspace has little/mid deformations that can only be predicted with a 3D MESH of actual measurements ( => i1Profiler’s “table” / DisplayCAL XYZLUT).

    i1Profiler’s “table” profiles should have the same kind of incompatibilities with Apple faulty/limited color managenet engine.

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