Help! Pro Res Export colour looks flat - gamma shift?

It's an issue of color-space, gamma, and levels issues. Exacerbated by Qt's players basic operating assumptions it seems.

First thing ... the Qt player is horrid in the way it treats many video files. It's "auto-enhancing for the viewer's enjoyment" rather than straight playing the file. On some PC systems with Nvidia GPU cards, you can go to the card's settings and set it like below ...

AND ... if that actually over-rides the Qt player's settings, the file should show properly. Note, what this did is set the GPU to over-ride the Qt player, and require Qt to honor the file as Full dynamic range, 0-255. Depending on the system, Qt may play files from PrPro in either of the two ancient (and in general no longer used!) DR's from tape days, 16-235 or 16-255. With an accompanying point or two drop in gamma. Ergo, shadows are mud not black, highlights gray not white, contrast lowered, saturation lowered.

Other issues that can be involved are base color space and monitor settings. PrPro is designed around the vastly dominant video standard of Bt.(Rec.) 709, which is totally sRGB and 0-255. If your moniter is ARGB, P3, something like that, PrPro will probably over-ride while it's active, but a file created in PrPro and displayed in sRGB, then viewed on a player on a system with say P3 color space for the monitor will not necessarily look the same. Ahem.

This is especially an issue on the Mac side of things, as many new Macs do use other color spaces.

As to uploading ... that ​depends​. Where I'm located, YouTube & Vimeo seem to quickly re-encode my uploads to the appropriate color settings. For many, there PrPro uploads are left on the initial upload setting, which mostly mimics the Qt look. For that, you can upload privately initially, go into your channel, select the recently uploaded video, select the "Retouch" option ... save immediately without even doing anything, and within a couple hours YouTube will normally re-encode the video so it displays correctly.

One final caveat ... you can't do anything about Gramma's green tv. Whatever you do, no matter how perfectly calibrated your system, as soon as it gets distributed via disc, web, or broadcast ... it will be viewed by people who do ​not​ have a properly calibrated system ... so if Gramma's tv is all green, your beautifully graded video will be ... green. Like everything else she sees.

And this ​definitely​ applies to clients!

Neil