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J
Jose5FEE
Participant
March 1, 2021
Answered

Black screen when importing QT Gamma Compensation LUT

  • March 1, 2021
  • 5 replies
  • 6208 views

So, here I'm coming with one of the main topics that Adobe it seems don't wanna sort out. As you know, per default the colors that you see on your monitor screen when you color grade don't match with what you export because Adobe thinks that all of us work on a broadcast monitoring system. 

 

They released a LUT called QT Gamma Compensation.cube that you can upload to your Effects > Lumetri Look / LUT folder when exporting. The thing is that when I upload the LUT everything turns black (screenshot attached), also when I export - I can hear the audio but don't see anything. I can choose any other LUTs and all of them work, so it should be a problem with the QT Gamma Compensation LUT.

Any thoughts?

    Correct answer R Neil Haugen

    And I have the same problem too....


    There's clearly some issues with that old LUT on the M1's at this time. Several other users have posted about it.

     

    You can create a rough equivalent by going into Lumetri, grabbing the Color Wheels Mids brightness slider, dragging it down a bit. Save as a .cube LUT on the Lumetri tab options at top.

     

    Then apply that via the Export tab LUT option, see what it does.

     

    Neil

    5 replies

    C
    coopersmith721
    Participant
    August 21, 2022

    Must change the hardware acceleration settings in project settings before exporting

     

      G
      Gibrán33818260byz3
      Participant
      December 12, 2023

      This actually worked for me, File / Project Settings / General / Renderer changed GPU Acceleration (Metal) to Engine Software Only. I don't know if this is ideal but at least I got my colors right with no black screen.

      Y
      Yuqi38060552byb8
      Participant
      June 15, 2024

      OMG! This really works for my M1 premiere 2020. So here is the steps.

      1. open Premiere, click file, go to project setting, change  GPU Acceleration (Metal) to Engine Software Only.

      2. export the media,t go to effects, select lumitri look, apply QT gamma composition , then export

      alia59418214
      alia59418214
      Participant
      May 12, 2022

      Hi Jose,

      Can you able to solve this problem?

      Thanks

      Kevin-Monahan
      Community Manager
      Kevin-MonahanCommunity Manager
      Community Manager
      May 12, 2022

      Hi alia,

      Sorry about this. I let the product manager know about this problem. I'll file a bug on your behalf in the meantime. You might try color correcting the clips using scopes, the Lumetri Color effect, etc. Let me know if you need help with that.

       

      Thanks,

      Kevin

      Kevin Monahan - Sr. Community and Engagement Strategist – Adobe Pro Video and Audio
      B
      Belinda24590497lr8w
      Participant
      May 24, 2022

      We're still having this problem, I also have an M1 & I have the exact problem. Please can you help solve the problem.

       

      Thank you

      Kevin-Monahan
      Community Manager
      Kevin-MonahanCommunity Manager
      Community Manager
      March 1, 2021

      Is this an M1 Mac? Let me know.

       

      Thanks,

      Kevin

      Kevin Monahan - Sr. Community and Engagement Strategist – Adobe Pro Video and Audio
      D
      defaultk430q3y83xi8
      Participant
      March 21, 2021

      I have same problem on M1 Mac

      М
      Максим23285852mlga
      Participant
      February 22, 2022

      And i have the same problem....

      R Neil Haugen
      R Neil Haugen
      Legend
      March 1, 2021

      The problem isn't Adobe, it's Apple's choices for mangling color management standards.

       

      For sheer proof, not even BlackMagic's Davinci Resolve can "fix" things. They just fudge files for Mac displays in a different method than Adobe. But with no more capability for those files to properly display outside a Mac system once modified.

       

      Why? Apple's ColorSync utility applies part of the Rec.709 standards correctly, ignores part, and does some very wrong. So the Mac display needs a 'different" file to show a "correct image" than a file that works correctly on any other system out there.

       

      Rec.709 is the standard used essentially by all cameras not producing for HDR at the moment. It is well established: sRGB color primaries, D65 white point, 2.4 gamma (2.2 if working in or for a bright-room viewing environment), both the camera (or scene) and display transform functions, screen brightness of 100 nits.

       

      Apple's color sync does some things, like the sRGB primaries, D65 white point.

       

      But then they apply what they call  "sRGB" gamma (which no one can find) ... which in reverse testing depending on who does the testing is between 1.95 and 1.96 mostly sort of.

       

      They apply the scene (camera) transform function but NOT the also required display transform function, and of course leaves the monitors up around what, 250-300 nits typically.

       

      Not hardly the same thing. That's not Adobe's fault nor is there any way Adobe can solve it.

       

      To get around Apple's choosing to be "unique" they offered the Display Color Management option which tells Premiere to look at the ICC profile of the monitor, and remap the image inside Premiere's monitors to get as close as possible to a proper Rec.709 image. This does help those working in PrPro on a Mac get a more correct image to view.

       

      They can't make ColorSync do the proper color management, so outside of PrPro they have no control. They offer the compensation LUT to make the export look similar outside of PrPro but only on a Mac/Retina display! ... as on any normal system, which would be any TV or most Android/PC screens, that image will now look too dark and saturated.

       

      Resolve chose to offer an additional export option, which rather than modifying the image adds another NLC tag to the image file header. Which ... gets ColorSync to actually work correctly.

       

      However, outside of a Mac again ... that extra NLC tag does the same thing as Adobe's comp LUT ... makes any other system show the file too dark and saturated.

       

      I've seen colorists (I work for and teach pro colorists) do exhaustive attempts to find some way to make some sort of setting or anything that will make the Mac ColorSync behave, and not trip up the files on every other screen out there.

       

      They can't find it. And note, most all of them are Mac-based people. They have more spent on their colorimetry gear and software than most of us spend on our entire computer/monitor setup. Neither they nor any of the experts that make the color calibration/profiling software colorist's use can get around the Mac color management choices.

       

      And of course, colorists never grade on a screen attached to a GPU anyway. They use an i/o device like those made by BlackMagic and AJA to get the signal out of the computer untouched by the OS and any color management the OS or GPU may be doing, and use either a LUT box between the computer and the screen or more likely a high-end grade 1 reference monitor (yes, that is a specific item) that can hold calibration LUTs internally that it applies to the image.

       

      So even though many colorists work on Macs, they never use the Mac monitor to grade an image.

       

      Neil

      Everyone's mileage always varies ...
      gerikp
      Community Expert
      gerikpCommunity Expert
      Community Expert
      March 1, 2021

      That was super interesting Neil. Also, very nerdy in a good way. Thanks!

      R Neil Haugen
      R Neil Haugen
      Legend
      March 1, 2021

      Thanks, Gerik.

       

      And that's all kinds of nerdy there! Sadly, that's a pretty simplified form of the answer you'd get from the folks that design the color calibration/profiling software for pro colorist's. CM is perhaps as nerdy as any discussion you can imagine. And I include real "rocket science" in that statement!

       

      I became somewhat knowledgeable about all this simply because I had to. As noted, I work for, teach, and deliver stuff to pro colorists. I have to follow proper CM even though I don't have a full Flanders or Eizo "grade 1 reference monitor". If I deliver something that is a bit off on audio, not a big deal, that they can correct or live with.

       

      If I deliver something that's off on the visual part however ... it's an immediate no-go. It comes right back at me and it's gotta get re-done before it will be acceptable. Because you simply don't deliver pro teaching to that crowd and get believed if you can't deliver pro image quality.

       

      Even with all the work I do to get and maintain calibration, I'm always nervous because I don't have that Flanders running an internal calibration LUT as my reference screen. What I've got comes "close" ... and I keep getting told my stuff is fine (and that it would come back immediately if it wasn't) ... but still,. I worry.

       

      Now, if someone wanted me to deliver for b-cast, I'd immediately shell out for the BM/AJA i/o device and that Flanders monitor ...

       

      Neil

      Everyone's mileage always varies ...
      gerikp
      Community Expert
      gerikpCommunity Expert
      Community Expert
      March 1, 2021

      I just tried this out and didn't have any problems. Sorry you're running in to roadbloacks. Do you get the same result with all other projects you are working on? Maybe try downloading the lut again just incase the file you have is having a problem? I don't know just some ideas.

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