Need help with contrast equalizer

[priort (Todd Prior)]

The original explanation is pretty good…

darktable and research

you might have noticed our equalizer tool, and been confused by it and the many controls. that’s probably partly because you didn’t see a similar thing before, we had to develop it first. very short history behind the ui is a powerful frequency domain processing technique, based on wavelets. the most commonly used wavelets are based on the lifting scheme [swe97], work in a data-independent way, and are decimated (i.e. the coarse coefficients are much more sparse than the fine ones). This is a …

Some people are not aware that the L and C tabs have 2 curves