Is anyone familiar with using the ACES colour space with Houdini?

I am trying to find if there is a method to convert texture maps so that they will show as expected when rendering with ACES. Used as they are with ACES they will render with a different look, understandably. I think I read somewhere that they must be converted somehow.

In general, as long as color management is set up correctly, you only need to properly interpret your textures when you bring them in.

In your material, in whatever texture node you are using there should be an option to set the source colorspace. The "automatic" default usually does a decent job, but you'll want to set it accordingly. Assuming you're bringing in sRGB images, set it to sRGB - texture or whatever your source color space is.

There's also an "ocio colorspace transform" node if you want to explicitly do the conversion in a dedicated node. Generally you'll br converting sRGB textures to ACEScg, but that really depends on how you've set up your color pipeline.

I am using a Principled Shader. In the Textures tab for Source Color Space there are only two options: Automatic and Linear. The Automatic option does not correct the image (it appears over-saturated an dark), while the Linear option is closer (not as saturated) but it is too light.

How would I use the ocio colorspace transform node?

Edit: I think I found a way to do this with the OCIO Transform node inside a VOP COP2 Filter:

https://paperkrane.io/articles/converting-image-textures-hdris-to-aces-in-houdini/ [paperkrane.io]

I found that I also had to uncheck Linearize Non-Linear Images in the File node since I used an SRGB texture map. The To Space: ACES - ACEScg gave closest result.

However the result is still darker and more saturated, so I added a Color Correction node to the Material and increased Gamma to lighten it.