Perhaps. The only other differences I can think of would be:
- Differences in choice of the value “a” in the algorithm - e.g. choosing a=3 is more costly computationally but should provide better results. I’d be shocked if RT were using 3 and darktable were using 2 though. This guy may simply not have tried darktable?
- GIMP often does all operations on gamma-encoded data
- Not even sure if RT is doing rescaling in the part of the pipeline that is linear-encoded vs. the part that is gamma-encoded. Probably something to dig into, if it’s the part that is gamma-encoded then it’s a candidate for moving it (or at least having the option to move it) in the future