For your information: I have installed #DisplayCAL on my #Linux #Mint machine. DisplayCal is a #FOSS; free and open software for screen calibration. I use it with my #Spyder5 from #DataColor. DataColor own sw does not support Linux. The initial profiling and measurement took an hour. I must read more how it works. But I manage to get a calibration done, which is needed, for the external monitor, still to find out about the internal laptop monitor. Good start anyway! #WalkingToLinux