SpeedXG
Screen Test
Cycle patterns to judge a monitor or laptop panel: solids, grayscale, and a grid for scaling issues.
Cycle solids, grayscale, color bars and a grid.
What to look for
Tinted grayscale means a bad profile or cheap panel. A warped grid can be scaling, not the LCD. Clouding on black is common on IPS backlights.
FAQ
Is this a colorimeter?
No. It is a visual screen test. For calibration you need a hardware probe.
OLED vs LCD?
Black should be deeper on OLED. Burn-in is an OLED risk — do not leave a static pattern for hours.