I have an older LG Flatron LCD monitor. I've been playing with the settings in some initial attempts at calibration, but the gamma settings don't relate to anything I've read. I know I should be aiming for a gamma of 2.2, but the only settings it allows are: -50, 0, and +50. I currently have it set at 0.

Can someone help me translate this three-point system into a gamma of 2.2 or ??? I realize it may be time to buy a new monitor, but that's not going to happen for a while yet.