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ImageTexture Gamma

Posted: Wed Mar 26, 2025 3:53 pm
by johan_D
Hello,
I just upgraded from version 2023 to 2024. I see that the gamma of the "octaneImageTexture"
is originally set to 1 instead of 2.2. I've tried some things, but I can't get good results with the gamma at 1. The colors are washed out.
It changes the 2.2 gamma of my old scenes to 1 (gammas other than 2.2 are not changed). All my assets need to be manually edited. If I have to set the gamma to 2.2, it also changes the results of the Roughness, Metalness maps, etc.

I saw that the color management seems to have changed, but it seems the correct gamma is still 2.2, so I don't understand.
Did I miss something?

Re: ImageTexture Gamma

Posted: Wed Mar 26, 2025 6:52 pm
by skientia
There are too many variables to precisely diagnose the issue. This general Octane Color Management Guide as well as this one specific to texture files should cover all answers to more than most questions (all besides some 3D DCC specific cases).

Regarding the exponent number (oversimplified and rather erroneously referred as "Gamma") depends on the input file (such as non-linearly encoded or linearly, detailed on the texture-files page).
Furthermore, the "management" depends on the signal processing pipeline, "internal sRGB" (default) or if OCIO is active and a config-file loaded. And so forth (multiple variables, cases, situations).

Re: ImageTexture Gamma

Posted: Thu Mar 27, 2025 9:48 am
by johan_D
Thanks for your help, I'll look into it, I'll go back to the old version so I can work.

Re: ImageTexture Gamma

Posted: Thu Mar 27, 2025 10:35 am
by skientia
It most cases, the difficulties are easily countered thanks to the aid from all the information available on the suggested pages.
Feel free to report back (with as much relevant information as possible) if facing an issue or how it got resolved, if solved.