I’m trying to sort out if it is possible to write out EXRs from Nuke with both ACES 2065-1 and DWAB compression.
I know from both the Foundry documentation and local testing that Nuke Writenodes (and their sister Shotgun Writenodes) will guarantee ACES primaries in the resulting EXRs if write ACES compliant EXR is set on in the Writenode, but that they will be uncompressed.
I want DWAB compression, so I set write ACES compliant EXR to off, but then upon inspection of EXRs written with this setting I find that while the DWAB compression is there (in the metadata and based on the much smaller filesize), the primaries are now Rec709.
This is all very strange as the Nuke file that I’m using for testing has Project Settings that are all set to ACES - ACES2065-1 in the appropriate attributes (working space, 16-bit files, float files) under the OCIO config aces_1.0.3. Additionally, all the Writenodes are set to the ACES - ACES2065-1 colorspace.
I’m using RV to inspect the EXR metadata. When I use Nuke ViewMetadata nodes to compare compliant vs. non-complaint rendered EXRs, I see an additional exr/chromaticities attribute with values in the compliant version, and the exr/compression attribute is set to 0. (I’m going to use the OpenEXR python module to see if that provides any additional information.)
A compositor here suggested I try adding a ModifyMetaData node before the Writenode with an exr/acesImageContainerFlag key set to 1, but based on the following I’m led to understand that it’s just setting the same metadata flag in the EXR header (and in testing the Writenode setting clearly trumps it since the Writenode is last in the chain):
Writing this out made me think that maybe we could add the exr/chromaticities key in a ModifyMetaData node, set to the acesDefaultChromaticites value, but it’s starting to feel like down-the-rabbit-hole madness to me.
Advice is appreciated!