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Rec709/Linear in ACES Project

PostPosted: Wed Apr 07, 2021 11:54 pm
by GreyCarl
Hey, I feel like I'm missing something basic.

I'm trying to set up a simple ACES project mostly as sanity check/final conversion for some shots we're delivering and I can't seem to figure out how to get Resolve to properly import Rec709/linear exr sequences into the ACES project. I've left the project set to No Import Transform and whatever Resolve is picking has the wrong color space, but gamma is correct. If I explicitly set it to 709 in the ACES Input Transform pull pulldown list on the clip in the Media tab as you'd expect the color space is now right, but it is presumably trying to re-linear-ize clips that are already linear.

The closest I can get is bringing it in with No Input Transform then putting a Color Transform effect on the node and converting it from Timeline to ACES. This does not seem correct obviously. So what am I missing?

Re: Rec709/Linear in ACES Project

PostPosted: Thu Apr 08, 2021 1:33 pm
by Jim Simon
I would presume you set the IDT to Rec 709 in the Project Settings, no?

Re: Rec709/Linear in ACES Project

PostPosted: Thu Apr 08, 2021 1:39 pm
by psbanerjee
ACES cc/cct are log color spaces. So, my guess is it's trying to convert your linear 709 to one of these log spaces.

ACES cc/cct is used only for image processing, not for delivery if you use 'none' for ODT setting. It will transform cc/cct back to linear ACES and output the non-graded archival EXR, if that is your objective.

Re: Rec709/Linear in ACES Project

PostPosted: Thu Apr 08, 2021 2:27 pm
by Hendrik Proosa
I can't check at the moment how it is named in Resolve but in OCIO ACES confs it is called Utility - Linear - Rec.709

Jim Simon wrote:I would presume you set the IDT to Rec 709 in the Project Settings, no?

This means footage has rec709 encoding curve applied, which in OP case isn't.

Re: Rec709/Linear in ACES Project

PostPosted: Mon Apr 12, 2021 6:31 pm
by GreyCarl
Hendrik Proosa wrote:I can't check at the moment how it is named in Resolve but in OCIO ACES confs it is called Utility - Linear - Rec.709


Yeah, there doesn't seem to be anything the corresponds to that in Resolve's implementation. Has anyone seen some sort of longer write up by Blackmagic on their ACES setup? I feel like it's treated a bit sparsely in the manual.