I posted a "User's Guide to High Bit Depth GIMP 2.9" to my website.
Some of the GIMP 2.9 code still uses hard-coded "sRGB-only" parameters.
Consequently, if you use GIMP 2.9 to edit images in wider gamut RGB
working spaces such as ProPhotoRGB or AdobeRGB1998, the affected editing
operations produce incorrect results.
The "User's Guide" tells you which editing operations to watch out for
and also provides some workarounds.
Some of the workarounds are simple, and some require making small
modifications to the source code and then recompiling babl/GEGL/GIMP.
Here's the link:
The Guide talks about color management and so gets a bit technical in
places. So if anyone has questions, please ask and I'll do my best to
Color management and free/libre photography
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