Colorists! Gamma shifts between QuickTime and FCPX?

Hi fellow users and colorists!

Here's my question: What gamma is my FCPx on, when my color space is set to Rec709?
Can I safely assume that with my Display Profile being set to Rec 709 Gamma 2.4, FCPX applies Gamma 2.4 as my working and output gamma?

I did a few tests and am fairly suspicious, hoping someone here can enlighten me on this:

My workflow is as follows:

My Mac OS X 10.15.3 Macbook Pro's Display profile is set to Rec.709 Gamma 2.4
I use DaVinci Resolve Studio 16.2 for my color grading and FCPx 10.4.8 for my Editing.

1. Graded a file in Rec 709 Gamma 2.4, exports it out using Resolve with the same 709 g2.4 tagging.
2. Opens it up in Quicktime Player 10.5, great, consistent colors with my Resolve viewer.
3. Imports it into FCPx, and I see a difference between Quicktime Player and FCPx

It seems that Quicktime Player is able to read the embedded gamma and transform/display it such that it is accurate with my Resolve viewer,

which begs the question, shouldn't FCPx do the same thing since they are both directly affected by the Display Profile selected? I have some screenshots attached to show the difference between the three applications (Resolve, QT Player, FCPX - using this workflow)

It seems that FCPx viewers do not use the gamma of 2.4, but possibly Rec 709 gamma that one could argue would be around 1.94.

Does anyone know if there is a way to monitor at gamma 2.4 using the FCPx viewer like how QuickTime does?
Or am I missing anything?

Thanks,
Zakk

Try using the default Display setting for your computer in System Preferences.

Hi Tom, thanks for your reply!

By default settings do you mean Color LCD profile?

If I want to deliver specifically to Rec 709 Gamma 2.4 for broadcast requirements, can I ask how do I set this up in Final Cut Pro?

Cheers,
Zakk

FCP uses the default color profile with ColorSync to maintain the appearance across applications. The display profile doesn’t alter the output. You would need to check the output on a broadcast monitor.

I do broadcast daily, don't have a broadcast monitor (cheap management), but I do just fine using the scopes. Learn to use your scopes and you'll be fine. And slap on the Broadcast Safe effect if you're feeling shakey about it.

Hi Zakk - having the same issue here with FCP interpreting the 2.4 footage as 2.2

Did you find a fix or workaround?

Tom Wolsky wrote:

FCP uses the default color profile with ColorSync to maintain the appearance across applications. The display profile doesn’t alter the output. You would need to check the output on a broadcast monitor.

I'm having the same issues and I don't understand your answer to the question. The question was how to setup final cut for a rec 709 2.4 gamma project. A 2.4 gamma clip from resolve looks different in final cut on m calibrated monitor and and my MacBook with default color profile. On QuickTime it looks fine. I guess final cut uses gamma 2.2. So what can we do, set our displays to gamma 2.2 and work with 2.2 gamma in resolve? 

While I'll never pretend to fully understand this gamma shift issue, I've dealt with it a lot using Resolve and delivering for clients who I know will be viewing on Apple computers. Long story short, I think the ColorSync system uses a perceptual gamma mapping, rather than absolute or relative ones, to map gamma onto a particular display calibration. A little background is required: Absolute and relative mappings of gamma curves to the display brightness/color calibration are straightforward enough, they more or less directly look at the gamma curves and then determine where a luma value and thus a color sits in the display space that follow those curves. Most PCs do straightforward conversion, as do iOS devices and iPads. MacOS does it differently though. I think it uses a perceptual interpretation of gamma. These don't behave consistently with the shape of the curve. This is because they were determined experimentally through tests of how real humans see contrast in different viewing conditions. Apple designs their computers with the notion in mind that people will be viewing them in brighter environments. Maybe to avoid all of the complaints from customers that their screens are too dark and that their videos look too contrasty when they're watching them near a window in Starbucks, Apple has just decided to bake into the color system an across-the-board policy of shifting the gamma to flatten the gamma curve a little. And because they assume people are looking at their iPads at home on the couch, these follow a more absolute/relative gamma mapping. This means that to get the right image in MacOS, you'll need to bypass ColorSync or load another display profile.

Some viewers bypass ColorSync, In VLC Media Player for instance, your videos will more contrasty and saturated than in QuickTime viewer with the same standard sRGB 2.2 display profile standardly used on most MacBooks. I think the solution, and please evaluate this based on your own experience, is to use an Apple monitor with a REC709 display profile when you're correcting in FCP and viewing in QuickTime. This should roughly show you the same brightness and contrast levels that you get on a gamma 2.4 television or sRGB PCs that are properly calibrated. Alternatively, you could click on the "Use Apple Display Color Management" in the Resolve general preferences, and you will see what you'll get in FCP and QuickTime. If you then color correct in a bright room, because of the perceptual gamma display mapping, it will be as if you were correcting at 100nits in a darkened grading environment and you will -- god willing -- see what you would on a gamma 2.4 calibrated television in a darkened room.

Hopefully I've managed to make this make sense. It's kind of difficult to explain...and maybe I've understood it wrong. But this is difficult to explain because Apple has given us little official indication of what it's doing with the gamma in its official documentation. This is just kind of a working hypothesis in internet forums.

thanks so much! this is the first time i kind of read something that makes sense. but what i understand from this is, as long as i dont use an apple xdr monitor with a rec709 profile, i wont be able to use an external monitor which is calibrated to rec709 2.4 gamma as final cut assumes im on something like a 1.9 gamma macbook display. i think this is wild.
or is there another way to bypass the colorsync in macos when using final cut?

I know. It's absolutely wild and infuriating. And it could all be solved with a toggle in the display settings.

To get around the gamma shift, you have to calibrate the monitor using an external calibrator in the gamma that you want to view in and for which the monitor is set up for (professional monitors by Eizo and BenQ have one-click controls to change the monitor gamma to match the display profile you want to use). The bad news is that ColorSync will just raise the gamma of that .icc profile.

But you can then take this calibration and generate a LUT from it using DisplayCal, then load that into an editing program, at which point you can view everything in whatever display space you want. Unfortunately, this is only possible with programs like DaVinci Resolve and Optimus video player because FCPX doesn't let you load a LUT in the general preferences. I've unfortunately found it not to be possible to bring the gamma down in color-managed apps like FCPX and QuickTime Player from the effective 1.96 ColorSync gamma. Adobe color-managed apps, which load your monitor's .icc profile and do their own magic with it bypassing ColorSync, display things well enough but they look to have more magenta in the skin tones (signaling a gamma mismatch) than on my calibrated PC monitors.

A workaround might be to make a viewing LUT for your footage in FCPX that you add onto the clips, or you could add an adjustment layer over the entire timeline with a curves adjustment. Just don't forget to remove these from the project before you export.