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+--- Thread: Preserving HDR information in EXR output from Blender in a 8-bit PNG? (/Thread-Preserving-HDR-information-in-EXR-output-from-Blender-in-a-8-bit-PNG)
Preserving HDR information in EXR output from Blender in a 8-bit PNG? - Mixxer - 03-22-2021
The only way to get the full dynamic range out in a render or bake is to save it as an EXR float from Blender. Not even saving 16-Bit PNG float will keep all the information in the highlights in Blender. But many applications call for another format other than EXR. Such as PNGs and even Jpegs.
So is there a way to compress the full dynamic range information from the EXR into a 8-bit PNG using Gimp? So basically all the HDR info in the EXR file can be seen in a 8-bit PNG and the highlights are not blown and the shadows are not crushed. In video, Log does basically that. Squeeze the dynamic range which normally couldn’t be handled by Rec709 into rec709.
Anybody knows how to do that with EXR to 8-bit PNG in Gimp? Again, I’m aware of the limitations of 8-bit PNG, but this is what I need to output to. So my question is really how to compress the dynamic range to fit the 8-bit limit.
Thanks
RE: Preserving HDR information in EXR output from Blender in a 8-bit PNG? - Ofnuts - 03-22-2021
Technically, HDR is just playing tricks to fit a bigger-that-8-bits dynamic into the 8-bits dynmic of JPEG.
There is no true HDR capability (tone mapping) in Gimp, but there are free apps that work quite well, such a Luminance HDR.
RE: Preserving HDR information in EXR output from Blender in a 8-bit PNG? - Mixxer - 03-23-2021
So I can't fit a bigger-that-8-bits dynamic into the 8-bits dynamic of 8-bit PNG using Gimp?
RE: Preserving HDR information in EXR output from Blender in a 8-bit PNG? - Ofnuts - 03-23-2021
Gimp can open EXR files, and the GMIC plugin has a tone-mapping filter (actually, several). But as far as I can tell, these filters expect several layers with various exposures (usually HDR is produced from several JPEGs corresponding to various EVs), and I don't know how well they work with a single high-precision layer as input.