Green Tint after 3DLUT calibration

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  • #27983

    Dean
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    Hi guys,

    I have recently discovered Plex / Kodi / MadVR and I have tried to create a 3DLUT for MadVR. Everytime I try this, the result is a green cast to everything. If I display grayscale steps in Kodi with the 3DLUT enabled, they are visually green. I’m sure that I am doing something wrong with the calibration process. I have tried changing the meter correction from the default Auto to WLED and also WLED PFS Phosphor but the result is the same. Any help would be greatly appreciated.

    Equipment:
    TV: Sharp Aquos LC70-LE960X
    OS: Windows 10
    GPU: Nvidia GTX 970 (Driver 456.71)
    GPU Settings : RGB Full, Brightness 55 %, Contrast 52% to avoid black crush

    DisplayCAL settings:
    Calibration: Whitepoint – D65 coordinates, White level – as measured, tone curve – Gamma 2.2 (no interactive display adjustment)
    3DLUT Settings: Defualt MadVR settings except Gamma 2.2

    #27984

    Dean
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    Forgot to mention, Meter is i1Display Pro

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

    #27985

    Vincent
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    Interactive display adjustmenmt, match numerically to d65 with proper correction or visual whitepoint yo whatever looks white.

    Then proceed as usual but make lut3d relative colorimetric

    #27987

    Dean
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    Thanks Vincent, I have used the visual white point editor to match numerically to D65 and the resultant white looks obviously green. I will just have to adjust it by eye for now.

    Is there a setting that will cause this? It seems like a common issue with the i1Display Pro.

    If I use relative colorimetric, will that adjust the rest of my grayscale to the white I chose, or just use the displays natural grayscale and base the color corrections around those points?

    #27989

    Vincent
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    Thanks Vincent, I have used the visual white point editor to match numerically to D65 and the resultant white looks obviously green. I will just have to adjust it by eye for now.

    You did not. Visual whitepoint & numeric match are different. You did visual whitepoint.

    Is there a setting that will cause this? It seems like a common issue with the i1Display Pro.

    Wrong colorimeter correction (most likely) and observer metameric failure (less likely, and if this happen it does not matter if you have lab grade device).

    If I use relative colorimetric, will that adjust the rest of my grayscale to the white I chose, or just use the displays natural grayscale and base the color corrections around those points?

    It should keep your display white color for greys +- minor rounding errors in a*b* plane.

    • This reply was modified 1 month, 2 weeks ago by Vincent.
    • This reply was modified 1 month, 2 weeks ago by Vincent.
    #28004

    Dean
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    You did not. Visual whitepoint & numeric match are different. You did visual whitepoint

    I should have mentioned that I am unable to get my TV on target using the interactive display adjustment. It shows an excess of blue. This is why I then used the visual white point editor. I had my colorimeter connected to another laptop running a 3rd party program, and I adjusted the visual whitepoint on display cal until my laptop showed the test patch was D65. I then connected the colorimeter to my pc (running displayCAL), clicked measure and it came up almost spot on the D65 co-ordinates.

    Now that I knew 2 programs agree that that shade of white was D65, I knew that it must be something to do with the colorimeter. This “D65”  shade of white is definitely tinted green.

    Wrong colorimeter correction (most likely) and observer metameric failure (less likely, and if this happen it does not matter if you have lab grade device).

    Do you have a colorimeter correction suggestion for my TV? I have tried WLED, WLED PFS phosphor and auto. It is a 70” Sharp Aquos. It has a wide gamut display and the backlight is supposed to be “Ultra Brilliant White” LED according to the marketing. I don’t know what correction would best suit this. Thanks for your help.

    #28020

    Dean
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    As an experiment I downloaded displayCAL on my laptop, profiled it and the results look amazing. No green tint whatsoever.

    I also tried the suggestion to use relative colorimetric on my PC. The results were slightly better but I seem to still have issues with tint at low IRE + banding out of black.  I have now noticed that whenever I use a 3D LUT, it seems to mess up the grayscale at lower IRE. Grayscale steps change from looking fairly uniform uncalibrated (although cool) to an almost rainbow effect with a MadVR lut installed.

    I’m suspecting either the NVIDIA card, or my display is just so badly behaved that a LUT can’t fix it.

    #28021

    Dean
    Participant
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    Further update, I have plugged my PC into another monitor and made a profile as well as a 3DLUT for MadVR. The results are great with no tinting or rainbow effect in the grayscale.

    At this point I can only assume that my Sharp LC-70LE960X is extremely non linear or something

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