Sean Tucker has a really interesting guide here on nailing skin tones, even when you’re color blind like I am: https://www.youtube.com/watch?v=yMjb7sMiAsg&t=791s
He basically just compares the CMYK ratios, and adjusts the curves of each. Is there an alternative to this within Darktable? I haven’t discovered a way to observe the CMYK ratios, or to bend the curves of each independently.
Alternative approaches to this are welcome as well.