How to Calibrate Brightness (Black Level)
Brightness controls the "black level" of your monitor. If it's too low, dark areas of images will look solid black (shadow crushing). If it's too high, blacks will look gray and washed out.
Adjustment: Use the Brightness Test pattern. You should be able to just barely distinguish the darkest blocks from the pure black background. Adjust your monitor's Brightness OSD setting until the #1 or #2 block is just visible.
How to Calibrate Contrast (White Level)
Contrast controls the "white level". If it's too high, bright areas will lose detail and become pure white (clipping). This is common in clouds, snow, or highlights on skin.
Adjustment: Use the Contrast Test pattern. You should be able to see the difference between the light gray blocks and the pure white background. If blocks #254 and #253 look the same as the background, lower your Contrast setting.
The Grayscale Ramp
A smooth grayscale ramp should look like a continuous, even transition. If you see vertical lines or "bands," it means your display has limited bit-depth or poor calibration (gamma issues).