Video exporting lighter - QT Gamma Compensation too dark.

[Kye27155270a8fc]

Hello, 

I am currently exporting videos with brand colours. I am adding an mp4 with brand colours to premiere to make minor cuts and transitions and then exporting. 

The video that goes into Premiere Pro is the right brand colour and it looks correct when in the timeline, however when I export it is way lighter.

I have attempted to export with QT Gamma Compensation but it's too dark. 

Shown in image the colours prior to export, after regular export, and after export with Gamma Comp. 

Please help 🙂

Thank you!

[R Neil Haugen]

First, are both you and your client on Macs, using the Mac 'standard' Rec.709 monitor settings?

Second, is this for web or broadcast/streaming?

Third, how are you determining that your monitor is actually "tight" to the full Rec.709 specs? D65 white point, sRGB primaries, display gamma 2.4, 100 nits monitor brightness?

Because if any of those isn't pretty spot on, you do not have a way to know that your export is ... anything. To start with.

Colorists use a breakout device ... by BlackMagic or AJA ... to get the signal for a reference monitor out of the computer without either the OS or the GPU touching the signal. They do not trust the view of any monitor connected via GPU.

Plus, they use pretty hefty calibration gear and pro calibration software to both study the monitor and create a LUT to use to bring the monitor all the way up to specs. And then, after installing that LUT in either the reference monitor itself, or the breakout device, they run a profile ... to check that the calibration is actually, in fact, tight to the specs.

In your case, an additional issue may be ... it sounds like you are on a Mac? If so, then ... there's another very fun (in a very not-fun way) issue. Apple, for some unique reason, chose to mis-apply the Rec.709 standard, using the camera transform of 1.96 as the display transform. So Mac monitors, set to the normal Mac setting for Rec.709,  display the media using the 1.96 gamma, which lifts the shadows notably. Rather than the broadcast spec 2.4 diplay gamma.

Ergo, the need for the gamma correction LUT. Which ... isn't a fix, as it only makes the export look "correct" on a Mac using gamma 1.96. But ... it's wrong on everything else.

For example, on my rig, which is to full Rec.709 specs and profiled, that LUT makes anything exported while using it, look so dark it's basically crushed blacks.

Also, there's another complication. As for any of the new Macs, which have the option of "HDTV" as a monitor space, that setting uses the correct gamma 2.4, and any media made using the gamma correction LUT ... is also showing way too dark.

So ... yea, it's a freaking mess. My colorist buds tend to either do straight up Rec.709 for all work, or for Mac clients, maybe apply the equivalent of an Adjustment Layer over the sequence, and just before export, use the Lumetri Color Wheels tab's Midtone brightness slider ... pulled down just a bit ... to lower the mids/upper-shadows brightness.

Trying to split the difference. Enough so it's darker but not too dark in the shadows on straight Rec.709 display, but dark enough it won't be too light on a Mac display. Joy.

Neil

[Größen33335763suua]

You write a lot complicated things, and you talk about Colorists wich have Equipment worth 20k $ but its not about that because davinci resolve can do it.  So the Question is why Davinci Resolve exports exact the same Colors/Gamma as the Original Picture, but Adobe Premiere Pro can´t do it.

[Größen33335763suua]

that means its clearly a fail by adobe, the proof for that is: davinci resolve does it correct.

[Größen33335763suua]

Why People should check their things and settings and do this and this, when they have not to do this with Davinci Resolve, Adobe Premiere Pro has to change, and not anything from the user side.

[R Neil Haugen]

Color management is ... wowza, way complicated. 

If you can't grasp a few simple concepts, well ... good luck in pro video!

For starters ... Rec.709 full standard includes the camera OETF of 1.96, as that seemed to get a wider data range recorded than straight 1.0 did. And it worked well with the CRT "tube" monitors in use at the time, which had an inherent 'gamma' of 2.4 due to the parts used.

And then after flat screen monitors came in, which were more linear in response. Bt.1886 was 'added' to the Rec.709 specs, to give a screen display that would match the still-in-use CRT monitors.

So for the last what, 15 years or more, with only flat screens in use, Rec.709 full standard has been camera OETF (transform) of 1.96, display gamma of 2.4.

I don't think that part is at all complicated.

Then Apple decided to apply the camerat OETF of 1.96 to the display.

Explain how that was correct, or ... followed any standard in use? Tell us why Apple using a "unique" display function was a good thing?

And according to your logic, BOTH BlackMagic Resolve and Adobe Premiere had been wrong all along! All professional users were doing it wrong!

As it was only after Apple introduced ColorSync with the odd display setting, that Resolve added the Rec.709-A option.

I'll not get into the whole NCLC tag mess, as well ... that truly is a deep, deep rabbit hole.

[Marius33844980hdph]

Hi, in case you're still having trouble try to check Display Color Management. If you export with QT Gamma Compensation it should look fine on Mac.

[Kevin-Monahan]

Hi @Marius33844980hdph,

Applying the Gamma Compensation LUT on export is no longer necessary for those Mac P3 screen users. With v.24, and later, you can choose this option in the Lumetri Color panel in the Settings tab. Check it out.

Thanks.
Kevin

[Marius33844980hdph]

Thanks, will check it out 🙂