Mike Schmitt

Good to know. I was worried about hardcoding the colorspace of the autogen .rat files. Thanks again for your help. Progress!

I think I figured it out. I noticed Houdini creates a .rat file from the .exr automatically.

So I added this line to the ACES config file

- !<Rule> {name: rat, extension: "rat", pattern: "*", colorspace: ACEScg}

To tell Karma that .rat files are also ACEScg

Now Karma CPU and XPU give me the same results when switching between "Color" and "Vector 3"

I think without this line, Karma XPU was interpreting the .rat file as Linear Rec 709.

(Though, Karma CPU isn't -- does this mean Karma XPU requires the auto generatied .rat file and Karma CPU doesn't?)

Here's my houdini scene + EXR image if you feel like giving it a try.