Display testing is visual
ScreenBlack provides browser-based patterns and tools that can make certain visible display characteristics easier to inspect. They are not laboratory instruments and should not be treated as a definitive diagnosis of panel hardware.
Results can vary
What you see can be affected by room lighting, viewing angle, browser behavior, scaling, source content, display settings and the characteristics of the panel itself.
Hardware decisions
Before returning, repairing or replacing a monitor, phone or TV, repeat the test and consult the manufacturer's specifications, pixel policy, warranty and support documentation.