Please let me know if I should raise github issues for either of the observations below.
#1: Wrong black levels?
I was editing a Panasonic LX7 raw, and found a colour shift when raising exposure.
Without raising exposure:
With raised exposure:
I noticed that the waveform showed different black levels for the channels. I checked in exiftool, and that indicated 128 for all channels, like used in darktable:
Changing the black levels allowed me to fix the colour cast:
#2: Hidden parameter(s)
I created a style using those black points, and applied that to another photo - but the geometry of that picture changed:
It seems that a non-adjustable, hidden parameter, crop right, also changed. I guess this is related to the LX7 being a multi-aspect-ratio camera. I was just wondering why the parameter is hidden.