Nerd stuff

Blender & ACES

Limitations with version 2.83 and up to 2.90.3 alpha

Today (12th of May 2020) I filed a bug or limitation when working with 8-Bit textures in Blender that need a colorspace transform. So I added some notes of other limitations I ran into in the last weeks and months while exploring Blender & ACES:

  • All color images should be EXR files in the colorspace ACEScg – in this way they don’t need any colorspace transform inside Blender.
  • Colorspace transforms in Textures (Input – Generic – sRGB Texture) will result in imprecise or sometimes wrong results when the image texture is a 8-Bit file! (the transforms should happen in floating point precision)
  • Non-Color image texture files e.g. bump or normal maps need to have the color space set to “raw” (no gamut or gamma mapping) – then there is not problem when using JPG/PNG files
  • Blender misses an option to select the OCIO file in the preferences – at the moment you must set the OCIO environment variable before starting Blender.
  • The list of colorspaces are not sorted in categories like it is in Nuke for example. The list is so large and long you need a giant screen to see them all and be able to select one with is at the end of the list – as a workaround you can temporally scale down the Resolution Scale smaller than 1.0 in the Interface/Display Preferences.
  • Be aware that you are working in a far bigger gamut of ACEScg – I wrote an article called Understanding Gamut with ACES and Blender about this topic.
  • The Blackbody shader which doesn’t really works in ACEScg.
Blender & ACES: The blackbody shader on a LED bulb of 2700K shows a wrong result – the light is too red.
Blender & ACES: Using a linear sRGB to ACEScg converted color value for the LED bulb – now the result looks right.

Go to the page for some more detailed information.