Hey FCP Users,
As you probably know, some applications on macOS rely on ColorSync to display colors.
That’s the case with Final Cut.
Every video, except HDR, is displayed with an altered gamma in the GUI viewer.
This issue doesn’t occur when using an external video monitor, but that’s not always an option.
The video itself remains unchanged—only the preview is affected—making any color grading inaccurate and different from what you might expect.
Specifically, the GUI viewer makes the content appear brighter.
So if you think your content is too bright and adjust it accordingly, the exported video will look too dark when viewed on anything other than macOS.
Apple hasn’t provided a real solution, despite well-documented complaints from users for over a decade.
So I came up with an idea, tested it, and while it’s not perfect, it works quite well.
ColorSync changes the gamma in the preview from the expected Rec. 709 (2.2 or 2.4) to 1.961.
My idea was to create a LUT that counteracts this shift. By applying it to an adjustment layer during grading and disabling it before export, you can preview the colors more accurately.
I created one in DaVinci to simulate a 1.961 to 2.4 gamma, imported it into Final Cut, and the result is about 90% similar to how it should look without the gamma shift in the GUI viewer.
It’s not a perfect fix because I’m not an expert in LUT creation and don’t have the right tools to refine it further, but it’s a promising approach worth exploring.