ACES space into ProRes?

Hi there,

sorry, don't know where to put this topic.
We are currently in pre-production for a short film and I wanted to test something for our VFX workflow.
I just wanted to try out a complete ACES-workflow between DaVinci and Fusion but EXR files a way to heavy for us. Is it possible to encode ACES to a ProRes 4444 (XQ) file? As this would dramatically reduce our storage needs for this project.
We don't need extra channels as normals, bump or something - just roto stuff and touch up work.

Thanks for any feedback

The preferred ACES workflow for VFX is ACES (linear AP0) EXRs out of vfx but if you have to cut corners I think you can also encode back to the camera's log space or use ACEScc (log AP1) as log space and save that to ProRes 10/12bit.

ACEScc and ACEScct are prefectly fine for this usage in combination with prores4444

Thanks for your answers.

But can you explain how to encode an ACES gamma space to a ProRes file?!
I set my project to ACEScct 1.2 without any input or output transforms (BRAW footage) and encode this to ProRes4444XQ. But in Fusion I cannot get back any detail from the highlights (as a basic task). If I encode the same project to EXR I can access the whole dynamic range inside of Fusion.

So how to get all this dynamic range inside the ProRes file?

But in Fusion I cannot get back any detail from the highlights

Do you enable flat pass to Always On in render settings?

Also, ACES 1.2 provides support for Color Space Conversion transforms – try setting output device transform to CSC – ACEScct.

But wouldn’t the VFX work take place on a Rec.709 or P3 monitor, with the taget colour-gamut LUT on?

How does the round-trip work?

ACEScct can have values outside of 0-1 range, if there are (and there usually are) any out-of-gamut colors, so this information will be lost. If you want to use ACEScct, you have to add Gamut Compressor DCTL at first. But it's sometimes better for VFX to have these out-of-gamut colors.
And ACEScc by itself has negative values in the bottom part of it's curve, even without any out-of-gamut colors. Its flare level is below 0 value. So it can't be used with formats like ProRes.

So, I think, the best option is to send your files in source footage color space and OETF, if you have to use ProRes. And then they just open it in Nuke with the corresponding ACES IDT.

But there are two things you should keep in mind:

1. Don't forget to use chromatic adaptation OFX to keep white point the same. As it will be changed if you use Color Space Transform OFX and you don't use Resolve 17.2 (there is a new checkbox for this). And in Resolve 17.2 you can set output to different CSC like Alexa for example.

2. In Resolve 17.1 there is a bug (fixed in 17.2), that doesn't let you go above or below ACEScct range with some of the source formats, if you set Output transform to ACEScct. And you have to set output identical to your timeline color space, which is either ACEScct or ACEScc with ACES color science, if you want to use Color Space Transform OFX for output.

So, in your case, it's probably better to make a duplicate of your timeline and just switch color science to a regular DaVinci YRGB for exports to VFX.