Wed May 27, 2020 9:55 pm
What exactly do you mean when you say Final Cut "interprets" your footage to be Rec 709? Are you sure you shot it in film mode and not video mode?
Final Cut offers two color spaces to work in: Rec 709 and Rec 2020. The color space is set in the FCPX Library settings. When you're importing Prores files shot with a Blackmagic camera that used the film dynamic range setting, you should import them into a Rec 709 library, assuming you will be delivering in Rec 709. They will appear as log footage (low contrast, low saturation).
You then have to normalize your log footage (just as you do in Resolve) into the Rec709 color space. Resolve has a number of ways to do that, including Resolve Color Management, ACES, the CST plugin, a camera LUT, or manually (usually by using curves).
In Resolve I use Resolve Color Management to normalize my log footage or I use the CST plugin, but in Final Cut I think your best bet is to use a camera LUT. Final Cut has built-in LUTs specific to many cameras, or you can get the one specific for your BMD camera from Resolve's LUT folder (which is in your computer's Library folder under Application Support/Blackmagic Design/Davinci Resolve).
The camera LUT will bring your log footage into the Rec709 color space and you can then use Final Cut's color grading tools to finish the grade. They're actually very good now and should be sufficient for a lot of people's needs, but Resolve offers a lot more and honestly I find Resolve does a better job with BMD camera footage. And as noted above if you're shooting on a BMD camera that can shoot Braw you might as well take advantage of that since you'll have more flexibility and smaller file sizes. But then you need to process your files in Resolve first, send them to Final Cut, and then back again to Resolve for final grading. A lot of people do it, but it's tedious.
I think the only case where you need to use a Rec 2020 library in Final Cut for footage that will be delivered in Rec709 is when you're working with ProRes Raw. If you try to import a ProRes Raw file into a Rec 709 library you get a warning. You can, of course, create a Rec 2020 library in Final Cut and work with your BMD footage in that space, but unless you're delivering to the relatively few people who have HDR-capable monitors or TVs you'll still have to render to Rec 709.
Resolve 18 Studio, Mac Pro 3.0 GHz 8-core, 32 gigs RAM, dual AMD D700 GPU.
Audio I/O: Sound Devices USBPre-2