ART and Sigmoid [solved]

[priort (Todd Prior)]

I recall going back you explained things nicely here…

I've finally tried ART and it is amazing!

Hi @JackH, well, that’s a lot of modules I’ll try: exposure compensation is just multiplication of each pixel (as a vector [r, g, b]) by 2^{value}, done in linear space, with no clipping tone equaliser is a bit more complicated. At a high level, this is a parametric tone curve that tries to preserve local contrast. The basic algorithm comes from @anon41087856 of darktable, on top of which I’ve added my own tweaks. In summary: build a tonal map by taking log_2(luminance(…