can anyone recommend what is the best procedure to increase the contrast on the librem screens?
I have read online that one can use xcalib and/or xgamma, but manning the xgamma tool suggests using xrandr. However, I have no experience with any of these and the oniine info is a little thin.
I find my screen could have a little more contrast, especially with the greys being too washed out.
How you acquire xcalib and xgamma depends on which distro you are using - for example, on Arch I installed the packages xorg-xgamma (official) and xcalib (AUR).
To set the contrast to 70% using xcalib:
xcalib -co 70 -a
To set the gamma to 0.4 using xgamma:
xgamma -gamma 0.4
After you’ve fiddled with these for a while and want to reset:
xcalib -c
To persist these settings, you could put them in your .xinitrc depending on your window manager.
You may also be interested in the topic Colour calibration and ICC profile - interestingly, I find the contrast on my Librem screen far too high, and in this topic we are finding a way to calibrate the screen automatically to known good settings using an ICC profile file.
Until then, hopefully tweaking the settings with these tools will help.