corona lightmix and beauty pass have different saturations or rather color space

[imokha]

when i render a final image in the vfb, and i switch to interactive light mix to edit my lights, the vfb suddenly turns desaturated, without touching any setting. what's wrong? i have attached two images the first is lightmix the second is beauty.
please help. I am using corona 12 hot fix 1 and 3dsmax 2025.3

[Aram Avetisyan]

Hi,

You are absolutely sure that lightmix and beauty are identical, right? (nothing was changed in lightmix).

If so, and if you are using OCIO workflow, share a screenshot of the OCIO settings and also try doing the comparison using Gamma workflow - see if the images are identical.

If they are identical (no desaturation) with Gamma workflow but differ with OCIO, we will need the scene (or a stripped down version of it) to investigate for a possible issue.
Thanks in advance.

[imokha]

nothing was changed in the settings, alright i will the scene please because i mostly use ocio workflow as it recommended by my company.
Also it does fine with gamma 2.2 workflow but only happens on aces config
https://drive.google.com/file/d/1xJHEDfYqRW7HRT6a4IqmiLI4KYBgKqTI/view?usp=sharing

[Aram Avetisyan]

Thanks for the scene.

I can confirm it is happening and this will be further investigated.
I will share the updates here.

[Aram Avetisyan]

when i render a final image in the vfb, and i switch to interactive light mix to edit my lights, the vfb suddenly turns desaturated, without touching any setting. what's wrong? i have attached two images the first is lightmix the second is beauty.
please help.

Please also tell which exact version of Corona and 3ds max are you using. Thanks

[imokha]

I am using corona 12 hot fix 1 and max 2025

[Steff]

Corona 12 Update 1 (Hotfix 1), 3ds Max 2025
The problem still exists, are there any possible solutions?
I'm attaching a detailed example:
New empty scene in OCIO color mode, neutral-lut.png file loaded as raw placed into the scene as environment map in screen mode.

https://forum.corona-renderer.com/index.php?action=dlattach;topic=43922.0;attach=207356;image
Here are the results of rendering from VFB for Beuty and LightMix:
https://forum.corona-renderer.com/index.php?action=dlattach;topic=43922.0;attach=207346;image
https://forum.corona-renderer.com/index.php?action=dlattach;topic=43922.0;attach=207348;image
Here are their Scopes:
https://forum.corona-renderer.com/index.php?action=dlattach;topic=43922.0;attach=207350;image
https://forum.corona-renderer.com/index.php?action=dlattach;topic=43922.0;attach=207352;image
EXR files just in case
https://forum.corona-renderer.com/index.php?action=dlattach;topic=43922.0;attach=207354
https://forum.corona-renderer.com/index.php?action=dlattach;topic=43922.0;attach=207355

As you can see, this is not just a lack of saturation, it is a color distortion, especially strong in the red channel.

[Aram Avetisyan]

This has been fixed for a while internally. Next daily build will most probably have this in it.
Please give it a try when it is out. Note that some tiny difference may still be expected, but there won't be a difference as in the original images posted.

(Report ID=CMAX-1402)
(Report ID=CMAX-22)