Rec. 709 IDT in HDR Projects

For a while now, most of the shows I’m grading are done in HDR and make use of ACES, both for grading and VFX. It is quite well known I think, that the inverse display Rec. 709 IDT breaks a lot of footage, when used in an HDR context (highlights get clipped, bandings occur, etc.). In DaVinci Resolve we can still use the “Canon 5D” IDT as a workaround, but in Baselight there isn’t a equivalent, I think.

The problem gets worse, or at least unwieldy, when VFX artists are tasked to composite Rec. 709 footage (still photography, news archival footage, etc.) into modern cinema camera footage in ACES.

There is also lots of old content that will need to be “upconverted” from SDR to HDR in the near future. Having an alternative “Rec. 709” IDT for color work would be incredibly important for those projects as well.

What are the plans to address this issue in the future?

For old low bit-depth and compressed media a simple per-pixel IDT will not work. For such cases in Baselight you could use BoostRange, which is a spatial inverse tone-mapper.
I think there is only so much you can ask for from per-pixel colour management.

(But having a relaxed IDT for video which does not fully unbuild the RRT-ODT is something sensible to ask for. This will be much easier to accomplish with a parametric tone scale model like in the current ACES 2.0 proposal)


Thanks! After your and the rest of the FilmLight team’s awesome support on the issue earlier this week, we’re using Boost Range with success now for the current project at hand :slight_smile:

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Try using the sRGB (Texture) IDT if available.
Saved me lots of headaches with SDR footage on a HDR timeline.

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Thank you :slightly_smiling_face: That is available, at least in DaVinci Resolve.