When you calibrate your monitor, you use a program/pictures to get colors correct per that program you are using (AKA a screen/monitor calibration program) I'm just using the same principle with IL2COD. Obviously it required more trial and error than just "adjust brightness until you don't see the 2nd line from the top etc."
But the principle is the same. You always calibrate to what your own eyes see.
I know quite a bit about graphics. You may have heard of one of my brothers
http://digitalblasphemy.com/