Something was strange: An image, developed to look nice in darktable became far too dark in The Gimp. I decided to re-run the usual Argyll procedures, starting by checking the monitor’s native gamma.
It reported gamma 3.4! No wonder The Gimp entered a dark mood.
The remedy was quite simple, though: re-set the monitor before running the native gamma check…
Ah! Now it is a pleasant 2.3.
Claes in Lund, Sweden