I have seen similar posts about people having a similar issue on iMac Pro's. Grading out footage only for it to turn out flat and washed out when we have exported it from premiere. I don't see the same problems when playing the exported file on VLC player. Will this affect the grade once I upload onto YouTube or Vimeo? This uncertainity has halted all of my grade with my current projects if anyone can assists me.
The issue, if you're on a Mac, is the rather unique way that Apple chose to apply color standards to Rec.709 media. And from all testing there isn't any actual complete "fix" across systems.
Rec.709 pro video standards have been very clear for years: sRGB color primaries, D65 white point, 100 nits brightness, gamma 2.4 assuming a moderately dark room (2.2 if in "bright" viewing environment). Plus applying both the "scene referred" transform function and the "diplay referred" transform function.
Apple chose to have their ColorSync color management system apply a different gamma-ish setting they call "sRGB", which isn't known to exist. From testing by Adobe engineers, colorists and color management specialists, it's listed as something between a 'normal' gamma of 1.95 and 1.96, but with an odd shape near the bottom.
And Apple chose to only apply the scene-referred transform function, not the second and also required display transform funtion. So ... between changing the gamma (shadow to brights curve) and leaving off the second transform, it presents users with a quandary.
Do you: adapt your media to look good within the Apple-sphere of newer Retina-display devices?
If so, the media will look similar within Mac devices in Chrome and Safari browsers and their QuickTime player. However ... outside of the Apple-sphere, it will typically be 'off', most often over-crushed blacks, dark shadows, and perhaps over saturated.
If you produce to the Rec.709 standards, your exports will look similar across the majority of devices out there but in the Apple-sphere, a bit light in the shadows and perhaps low in saturation.
Adobe came up with the "Display color management" option in the preferences to allow users to tell the app to look at the ICC profile for the monitor, and re-map the image shown in the Program monitor to a correct, fully adjusted Rec.709 image on whatever monitor one is working with. And it does a pretty good job.
So you will see your media within Premiere at a fairly proper Rec.709 view.
But ... outside of Premiere in the Apple-sphere, well ... you see the problem yourself. So their option to 'fix' that for Mac users is a LUT applied on export that mods the file to show 'correctly' on a Mac. But ... outside the Apples-phere, that file will be over-saturated and dark.
BlackMagic came up with a slightly different option. They have an export setting option for Rec.709-A. And yes, A is specifically for Apple.
It applies a different NLC tag to the file header, so that the Apple ColorSync utility will actually use the proper gamma and the scene-referred transform function. Yea!
Um ... but the problem with setting that NLC tag on any media viewed outside the Apple-sphere, is you will still have the same problem as applying the LUT Adobe provides on export: dark shadows and over-saturation.
Yea, it's a mess. I spend much of my time working with colorists, who tend to be Mac based, and they have no solution for this either. Other than ... setting up their systems for proper full-on Rec.709 and working away, and at times providing properly 'fixed' devices for their clients to use to view the results.
Frustrated? Yea, so is about everyone. One colorist had a thread recently on LiftGammaGain where he went through about a bazillion tests trying to find a way around this. Fascinating to read through his trials and tribulations, very well done step-by-step testing of every option he could think of. Very well documented and explained.
And nothing ... zero, zip, nada ... could get around this disparity in the application of 'standards'.