How to use this test
- Clean the screen using the manufacturer’s instructions, then choose its native display resolution.
- Open the white background in fullscreen. Look for fixed dark points, then repeat with red, green and blue.
- Choose black and inspect for fixed bright points. Change the background manually when you are ready.
- Press Space to hide or reveal the controls in fullscreen; click the background to reveal them. Escape exits fullscreen. Record only what you actually observe.
Read the observations
A fixed dark point on white and multiple primary backgrounds may indicate a non-emitting pixel or subpixel. A fixed bright point on black can indicate a continuously illuminated subpixel. Dust, reflections and image processing can look similar. A screenshot cannot normally capture a physical panel defect: compare the screen itself across backgrounds and, if possible, another input source. Record the location and conditions for a support request rather than relying on an automatic verdict.
What this test cannot tell you
The browser has no sensor that sees your panel. The saved report contains your selected background and your own assessment, not a detected defect count. Browser color management, display scaling and panel technology can affect inspection. Warranty acceptance depends on the manufacturer’s pixel policy. No flashing sequence or pressure-based repair is used.
Need a closer comparison? Dead pixel or stuck pixel: what can you observe?.
Questions about the test
Can I use this as a white screen test?
Yes. Choose White and fullscreen. The other colors are available for a more complete visual comparison.
Will this fix a dead pixel?
No. It is a visual inspection aid. Contact the manufacturer if a persistent defect is visible.
Technical references
Method version 2.0 · Page updated 2026-10-20