Gray Matter & Gray-Scale Ramp Monitor Calibration
Below is a graphic with a gray-scale ramp for you to use to adjust your monitor so you can see as many shades of gray as possible.
Since there are so many combinations of hardware and software, I can't give precise, step-by-step directions on calibrating your monitor. Howevever, there are two main places to look to adjust your system. Directly on the hardware itself. And from within the Operating System using software. Perhaps there is 3rd party software available for you.
If you are using an LCD, which tend to be sensitive to the angle the screen is looked at, also try tilting the screen to see how to angle it best.
1. Locate the controls on your hardware to adjust them first. Watch the graphic below as you make changes.
2. Locate the software controls on-screen to adjust the monitor, move this window and that window so they are next to each other and as you make adjustments in the software interface note how they affect the ramp below. It may be the case that as you make adjustments to the software interface the changes are not immediate, but you may have to click an "Accept", "Apply", etc... button to make them take effect. So repeat the process until you can see as many of the scales of gray below. Black on the left, white on the right, 8 shades of gray going to 50%.