video card gamma tables 1D LUT calibration is non-linear

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  • #13679

    RickardL
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    I am bit confused by this message which pops up:

    The display device’s video card gamma tables 1D LUT calibration is non-linear, but the 3D LUT contains applied 1D LUT calibration. Make sure to manually reset the video card gamma tables to linear before using the 3D LUT, or create a 3D LUT without calibration applied (to do the latter, enable “Show advanced options” in the “Options” menu and disable “Apply calibration (vcgt)” as well as “Create 3D LUT after profiling” in the 3D LUT settings, then create a new 3D LUT).

    I am running DisplayCal on my laptop and using madtpg on the 2nd/virtual screen which is connected through
    HDMI to the eecolor box and then to the TV. I don’t want any interference from the laptops video card
    since that will not be part of the display chain (bluray player -> eecolor -> TV).
    Should I have “Apply calibration (vcgt)” unticked or not?

    #13686

    Florian Höch
    Administrator
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    If the laptop is not part of the chain in the end, then you can safely ignore this warning. It would only be a problem if you tried to use this 3D LUT through the eeColor with the computer as the source, because then the calibration would be applied twice (once through the video card, once through the 3D LUT which has the vcgt already applied).

    #13693

    RickardL
    Participant
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    So, for my situation, it doesn’t matter if I have it ticked or unticked then?

    #13698

    Florian Höch
    Administrator
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    So, for my situation, it doesn’t matter if I have it ticked or unticked then?

    In your case the calibration is nonlinear and so it needs to be incorporated into the 3D LUT, as you’re not going to use it with the computer as the source.

    #18706

    Karda
    Participant
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    Hello Florian,

    for me it is exactly the case, that I am using my PC as the source, which is connected to the eeColor Box (where I transfer the 3d lut to) , which then is connected to the projector. So what do I need to do, getting the message?:

    “The display device’s video card gamma tables 1D LUT calibration is non-linear, but the 3D LUT contains applied 1D LUT calibration. Make sure to manually reset the video card gamma tables to linear before using the 3D LUT, or create a 3D LUT without calibration applied (to do the latter, enable “Show advanced options” in the “Options” menu and disable “Apply calibration (vcgt)” as well as “Create 3D LUT after profiling” in the 3D LUT settings, then create a new 3D LUT).”

    #18710

    Florian Höch
    Administrator
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    See above.

    #18712

    Karda
    Participant
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    Sorry, I read the above, but I didn’t understand. The other people discribed a configuration in which they aren’t using the eecolor Box, unlike me. Which means that I can not apply your advice given above to my configuration. So do I need to “to manually reset the video card gamma tables”? And if so, how do I do that?

    #18715

    Florian Höch
    Administrator
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    other people discribed a configuration in which they aren’t using the eecolor Box, unlike me

    I’m not sure where you got that idea from. This thread is exclusively about using the eeColor box as 3D LUT holder.

    #18718

    Karda
    Participant
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    Oh I see now. But the difference is that Rickard Lin , as discribed in his first post, uses his bluray player as the source. Whereas I am using my PC. So my configuration is different and I can not apply your advice given above because as you wrote “If the laptop is not part of the chain in the end, then you can safely ignore this warning. It would only be a problem if you tried to use this 3D LUT through the eeColor with the computer as the source”.

    So this is my case -what do I need to do regarding the gamma tables?

    #18745

    Florian Höch
    Administrator
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    You want to avoid having the calibration applied twice. If it’s part of the 3D LUT, you have to reset the video card gamma table when using the 3D LUT. If you don’t want to to that, don’t apply the calibration to the 3D LUT.

    #18787

    Karda
    Participant
    • Offline

    I’ve now found the mistake, -the cause why the image always looked too bright/washed out after profiling and using the 3dlut. It was actually something I thought I had adjusted some time ago:
    The brightness settings of the projector were wrong. When I checked it, there were no flashing bars on RGB-level 17, 18 and 19. (I think in technical terms on might say that there was clipping above the real blackpoint!?)
    So I assume that in order to compensate for that, to not lose details in the dark areas, the profiling
    pushed the overall brightness some RGB-levels higher.
    Now I adjusted it and the perceived brightness stayed the same, only the colors were corrected by the 3dlut and
    the gamma curve was adjusted. The image now looks very pleasant.

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