I've found something.
My display has DVI and VGA inputs. I am using DVI->VGA adapter for ANALOG input for my monitor. The ANALOG input is too bright, like described above.
If switch to DVI, then colors/brightness/gamma are fine.
So the problem is with ANALOG output from VGA.
I tried with different DVI->VGA converter, same issue - too bright display.
I can't switch permanently to DVI, because I need DVI for other machine with HDMI->DVI adapter.
I've found something.
My display has DVI and VGA inputs. I am using DVI->VGA adapter for ANALOG input for my monitor. The ANALOG input is too bright, like described above.
If switch to DVI, then colors/ brightness/ gamma are fine.
So the problem is with ANALOG output from VGA.
I tried with different DVI->VGA converter, same issue - too bright display.
I can't switch permanently to DVI, because I need DVI for other machine with HDMI->DVI adapter.