IPR Color Differences

[james_conkle]

Hi-

After reading Elsksa very helpful blog and reading several other posts on this forum I've decided to post this thread since my "Google 'Fu" has run out on this one.

I have my OCIO config (1.0.3) defined in my system Environment Variables that Houdini is picking up in it's color settings. The applications I use to review my renderings are looking at this same OCIO config.

Inside Octane for Houdini I have my ROP setup to "Automatic Intermediate Color Space" and a Color Space of "ACEScg". The OctaneRT OCIO view is set to "ACES" and "sRGB". The look is set to "OCIO Use View Look". I'm saving uncompressed .EXR files of the beauty pass - no AOV, post effects or denoising.

The applications I use to review my renders are also set to OCIO 1.0.3 and interpreting the footage as ACEScg and the view is set to sRGB. I'm using both DJV and Davinci Resolve to view the renders and they match each other but neither match Octane's IPR.

[juanjgon]

Do you know if the old OpenGL IPR or the MPlay IPR (with MPlay configured to use the right OCIO 1.0.3 config) have the same problem?

Thanks,
-Juanjo

[james_conkle]

Just tested this and all options in Houdini (new IPR, old IPR and MPlay) and they all match exactly - so that's good!

I just compared against Houdini, Fusion and DJV. It looks like they all have some discrepancies. So that sounds like it's either something on my end or a limitation of OCIO/ACES which doesn't seem right. I'll do more digging and report here if I find anything.

[elsksa]

Hi James,

Thank you for the kind words.
I remember briefly discussing with you either here or on Discord (or both) but do not remember the details.

ACES is in most cases prone to nonnecessity. I'd recommend Filmic and can assist with it if needed.

I have my OCIO config (1.0.3) defined in my system Environment Variables

Even though it is not recommended to use ACES, is there any reason to be on 1.0.3, which is not the latest version?

Inside Octane for Houdini I have my ROP setup to "Automatic Intermediate Color Space"

That's correct.

and a Color Space of "ACEScg".

Which one? When set to "Automatic...", there should not be any "ACEScg" in the global OCIO/CM settings.

The OctaneRT OCIO view is set to "ACES" and "sRGB".

I am assuming, it's the ACES-sRGB Output that is selected? ACES is implicitly referring to ACES 2065-1 AP0 being a scene-referred linear interchange color space. Therefore, it can not be "ACES and sRGB" and rather is "ACES-sRGB" from the Output options, simply said.

The look is set to "OCIO Use View Look". I'm saving uncompressed .EXR files of the beauty pass - no AOV, post effects or denoising.

There are, by default, no OCIO Looks with the published demo-ACES-OCIO configuration file. It can be set to "none" as well.

The applications I use to review my renders are also set to OCIO 1.0.3 and interpreting the footage as ACEScg and the view is set to sRGB. I'm using both DJV and Davinci Resolve to view the renders and they match each other but neither match Octane's IPR.

I'd recommend Fusion, the standalone if you have a Resolve/Fusion Studio License, or the Fusion tab in Resolve.

[james_conkle]

Elsksa -

Interested in why you recommend not using ACES? What is this "Filmic" you refer to? If you're talking about using Octane's camera imager I prefer to use ACES for many reasons even if I'm getting slight variation across applications.

I'm using OCIO 1.0.3 since it's the latest version supported by all my applications.

Here is where "Automatic intermediate color space" is enabled you can define the color space of the output file: