Ok ... you got both things then, so here we go. Grab a cuppa your fav beverage ...
HLG TO Rec.709 Color Management
At this time, you may (wisely) choose to work within a Rec.709 color space. To do so with clips that have HLG color space tags ...
- in the Project panel, select one or more clips;
- right-click then select Modify/Interpret Footage;
- at the bottom of the Interpret Footage dialog, select the Override-to option and set that to Rec.709;
- go back to the seqeunce, click inside the Timeline panel so it is "active" with the blue outline;
- go to the main menu item Sequence/Sequence Settings'
- at the bottom of the top section is the new sequence color management (CM) option
- make sure this is set to Rec.709;
- redo all color corrections on the timeline;
- export using SDR/Rec.709 presets, ones that do not have HLG or PQ in the preset name.
This way you will get a predictable Rec.709 file both on your sequence and in your export. You can check by re-importing the exported file into Premiere and checking it against the original sequence.
That's the easy thing, because "we" can actually solve it. Now ... for the hard part ...
Rec.709 Inside/Outside Premiere Pro on a Mac
(Note: I work for/with/teach pro colorists, mostly based on Macs using Resolve, and I work with Resolve daily myself. My colorist buds are furious with Mac over this issue btw.)
The Rec.709 Standard
The Rec.709 standards require the use of two transforms in the full system: a camera (scene) transform of 1.96, and a display transform of 2.4.
The latter was added in the Bt.1886 addendum when 'we' went from the old CRT (cathode ray tube) monitors to digital flat panels. As the CRT monitors had essentially a 'native' response equal to the Bt.1886 transform. And this has been a routine and required part of all professional video production for years.
Premiere Pro has always been built to follow the professional standards such as for Rec.709, including the assumption that all monitors will be set and controlled by the user, strictly to the Rec.709 standards ... 100 IRE/nits brightness, sRGB color space, and gamma 2.4 for the display settings.
The Mac ColorSync Utility settings for Rec.709
Apple created their ColorSync utility to handle CM (color management) for their Retina monitors. However they chose to apply the Rec.709 camera transform setting of gamma 1.96, and not to apply the required display transform of 2.4. No one knows why.
So any video player that allows ColorSync to do color management on a Mac displays 'standard' Rec.709 media with gamma 1.96. This includes QuickTime player, and Chrome and Safari browsers.
What does this gamma setting do to the image?
This lower gamma sets a brighter shadow area for the image, making the whole image look brighter. You can recreate this yourself in Premiere by going to the Lumetri panel and using several tools.
For instance, in the Color Wheels tab. Slightly lift the Shadow tonal control slider, and a bit less lift the Mids tonal slider. Or using the Curves tab, click about a quarter of the line up from the lower left corner, and slightly pull that "up". These are both very much a "gamma" type adjustment.
How do we fix this?
Good question, as the problem is actually pretty simple: the image shadows are displayed lifted by the off-gamma setting. So a fix should be possible, right? Partially, yes, but completely ... no.
The partial fix, for working on a Mac ... and many PCs also ... you should have the preferences option for "Display color management" option checked on. This makes Premiere stop assuming your monitor is Rec.709 compliant. Instead it will check the ICC tag for the monitor, and adjust the image within Premiere such that, on that monitor, you get the closest image to Rec.709 Premiere can manage.
This doesn't fix the ColorSync issues outside of Premiere, but does give you the best visual you can get of the data within Premiere. Of course, your scopes are always more accurate for exact things like white & black points, and setting actually neutral neutrals, than your eyes anyway.
But there is no "complete" fix possible. Sadly.
Because there isn't any known way to create a file that will look the same when displayed with two diffrerent gammas are used. Within the Mac-osphere, outside of Premiere, this file will be seen with a 1.96 gamma setting. Producing the "lifted shadows".
For all other systems, including any broadcast compliant Rec.709 systems, the file will look "normal". As it did within Premiere Pro.
So on your Mac, outside of Premiere, your Premiere exports will be displayed lighter due to the Mac Rec.709 gamma setting. On my PC, with a highly calibrated and profiled system (profiling tests the calibration for charts showing the actual results) ... that file will look very much like it does within Premiere on your Mac.
The Workarounds provided by Adobe and BlackMagic
The Adobe devs provided a "gamma compensation LUT" to be used at export on Macs if the user chooses. Which will darken the file so it looks similar outside of Premiere, on Macs with ColorSync, in apps controlled by ColorSync.
The BlackMagic devs provided an export preset called "Rec.709-A", and the A is explicitly for Apple. This option applies a different NCLC tag to the file header. This tag is officially "unspecified" in the NCLC listing. It doesn't have a universal ... use. But the BM devs had found that if they included that tag, ColorSync would for some odd reason apply the correct 2.4 gamma to the display of the file.
The failures of those workarounds
For both, the problem is that although they mostly work within a Mac app controlled by ColorSync, both options will normally cause the file to be displayed way too dark and oversaturated on all non-Mac systems.
So ... this is a very notable "thing", and ... it's what it is. You can't "fix" this. Just choose which poison you prefer.
Neil
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