I have a Dell Precision 6600, under 16.04LTS. Sometimes I find that colors turn in general to somewhat gray (as it is now, and I cannot get out of this). Then, for some unknown reason, the screen comes back to normal.
Checking pure white (FFFFFF) for instance shows as gray, in any application. I tried answers here:
What can I do to solve this? A reboot (or even a logout) possibly solves this, but I mean to identify the cause and solve it without logging out.