First, I have Manjaro with Gnome 3.16.
By default, my screen looks unreadable, so I put in
xcalib -gammacor 1.3 -alter in order to fix it every time I log in.
It seems to work, but that adjustment is reverted in one or two seconds. If I apply that command manually after, the change is not reverted.
So, I believe that Gnome manages the screen color in some way, but I don't know how to disable it (I have tried to do this in 'Color' configuration, with no result). Could you help me, please?