Banding when using Display Color Management

[sanderdelange]

Hi All,

I recently installed Premiere Pro CC 2020 after I did a full Windows reinstall on my computer, so it's a clean install. With CC 2019 I used to enable Display Color Management to simulate the gamma curve of a Rec709 monitor on my calibrated sRGB monitor. With CC 2020, however, I notice extreme amounts of banding when enabling Display Color Management.

When I export a still, open it with Photoshop and set the proofing profile to Rec709 (gamma 2.4), I get a correct picture. Is anyone else experiencing the same behaviour? I've included some screenshots below:

Premiere Display Color Management turned onPremiere Display Color Management turned offPhotoshop proofing profile set to Rec709 (gamma 2.4)

[R Neil Haugen]

What gamma is the monitor providing, either by setting or 'native'?

If it's either 2.2 or 2.4, I'd just leave the EDCM off.

Neil

[sanderdelange]

My display is calibrated to sRGB, gamma 2.2. I normally keep the display color management off until I'm color grading. Then I turn it on and off to check whether the shadows aren't becoming too dark when viewed on a Rec709 screen, because I don't have one connected to my computer.

[R Neil Haugen]

I work with colorists regularly. Their comments in such situations is the with computer screens the difference between 2.2 and 2.4 won't bexany more if as much as the variations across the screen itself. One of the main reasons for getting a pro broadcast monitor being to get that reliable uniformity.

I run a full calibration via i1 Display Pro and check by running a profile with Lightspace/Resolve connected to check my calibration. I'm a bit banal about it.

But still, with your gear, I would not expect a really notable difference between 2.2/2.4. I would leave the EDCM off and get the work out.

The display differences screen to screen out in the wild are all going to be far more dramatic than this.

Neil

[sanderdelange]

Hi Neil,

I still like to turn it on because the shadows are darker on a rec709 display.

Anyways, the setting still has the extreme banding bug which isn't present in other Adobe applications. A friend of mine also has this problem on CC 2020.

[R Neil Haugen]

In a properly setup room, darkened (NOT blackended!) with a bias light, I can barely tell the difference between 2.2 and 2.4 on the monitor. Given that once it goes Into The Wild, you have no control ... someone will be on a phone in bright sunlight and another on a super-bright screen in a dark room ... that tiny difference is pretty much a non-worry.

I do wonder about your monitor ICC profile and calibration and/or settings. I can't replicate this. And what EDCM does is make Premiere look at the monitor ICC profile used by the OS, and set accordingly.

I know a lot of folks using EDCM, and haven't seen this elsewhere. Which leads me to posit that something in your screen setup isn't exactly spot-on. Monitor settings, calibrations, profiles, ICC profiles (separate from monitor profiles) ... it's enough that colorists have LONG threads on sorting out the issues. It's really very easy to have something "off".

Neil

[sanderdelange]

I removed my display calibration profile from Windows and the whole banding issue has gone away. When I re-installed the calibration profile, the problem came back. The weird part is that other color managed applications are working fine when soft proofing etc.. Everything works fine with both Adobe and non-Adobe apps; except for Premiere. 

Both monitors I have are software-calibrated using DisplayCAL, just as they were before this problem occurred. The problem only arises on the monitor with the active calibration profile. So if I remove the calibration profile for one monitor, that one won't have the banding.

I'll try installing PP CC 2019 to check it's behaviour when using EDCM.

[sanderdelange]

Premiere CC 2019 doesn't have this issue at all.

I opened up an older project in CC 2019 and turned on EDCM and the picture was just fine. When I fired up the same project in CC 2020 (and let it convert to a 2020 project) the banding issue was back again.

This can't really be anything other than a bug in the latest Premiere version.Premiere Pro CC 2019 with EDCMPremiere Pro CC 2020 with EDCM

Also, my monitor is calibrated to the sRGB gamma curve, not flat 2.2. I think that explains why I'm seeing quite a change in the shadow brightness, since the sRGB curve has gamma 1.0 near black.

[R Neil Haugen]

I like the way you're testing things, that's a good process.

I do have one quibble ... video should never be considered straight "photo" sRGB. Video sRGB standards involve both the camera or "scene-referred" gamma, and the display-referred gamma ... creating essentially an expected result of gamma 2.4. That is what nearly all pro colorists set for, as that is the broadcast and streaming standard. Period.

For "bright viewing environment" expectations a gamma of 2.2 will work fine, and some prefer it. Most colorists I know simply deliver everything that isn't HDR (and there's not that much delivered pro in HDR yet) in Video sRGB/Rec.709/gamma-2.4/100-nits-brightness according to b-cast standards.

Steve Shaw of LightIllusions calibration software has many "white papers" on their site concerning proper setup for monitor calibration and use. I do suggest people try and wind their way through them as there's a mountain of information there.

Have you done a puck/software calibration of your monitors, or simply using a software calibration regime? The later of course doesn't tend to be nearly as accurate. As far as say colorists would count "accurate".

Neil

[sanderdelange]

About your question regarding my calibration; I've calibrated my monitor as much as possible with a puck and the HCFR software, after which I did a software calibration with DisplayCAL because my monitor doesn't have very fine controls.

I'm getting some interesting results here. I've (quickly, for testing purposes) recalibrated my monitor to a flat 2.4 pure power curve and the whole banding issue has seemingly disappeared from Premiere, or it has become invisible since the changes are so small.

Also, thank you for your info on calibration standards. As a second-year film student this is much appreciated!

[R Neil Haugen]

You should "join" the LiftGammaGain forum, a pro post-processing forum heavily attended by colorists and some major tech/software brains like Steve Shaw.

The discussions on many things especially calibration and monitor questions tend to be long and detailed. Also very informative.

And fun at times.

Glad to hear the gamma change works of course!

Neil