Instructions: Track your eyes on the moving line. Look for artifacts.
This is useful for checking for temporal elements of your display refresh. Faster moving line is better/easier for detecting artifacts.
- Detect PWM dimming in LED-backlit LCD displays. Lowering monitor brightness may reveal PWM effect of multiple separate vertical lines (rather than one vertical line).
- Detect DLP rainbow artifacts, or temporal noise on Plasma/DLP displays.
- Tilting of the line can also occur on CRT's and some LCD's, especially at 60Hz. This tilt effect is caused by display scanning.