Red Dead Pixel Test
A red dead pixel test fills your screen with pure red (#FF0000) to reveal pixels with a failed red subpixel — appearing as black or cyan dots against the red background. Red also exposes color uniformity issues: if parts of the red screen appear darker, more orange, or less saturated, your panel has uniformity variance. Three colors (red, green, blue) must be tested individually to find all subpixel defects, since a failed blue subpixel is invisible on a red screen.
Ready to scan your monitor
The test displays 6 solid colours in full-screen — Black, White, Red, Green, Blue, and Gray. Scan the entire screen for any pixel that doesn't match.
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How to Read Results from the Red Pixel Test
| Defect Count | Rating |
|---|---|
| 0 defects | Perfect |
| 1 dead pixel | Acceptable |
| 2–5 defects | Borderline |
| 6–10 defects | Degraded |
| 11+ defects | Failing |
Frequently Asked Questions
Why do I need to test pixels on a red screen separately?
Each pixel contains three subpixels: red, green, and blue. A defect in only the red subpixel is invisible on a white or green screen but shows as a cyan dot on the red screen. Similarly, a failed green subpixel appears magenta on green, and a failed blue appears yellow on blue. To find all subpixel defects, you must test all three primary colors individually plus black and white.
What does a cyan dot on the red screen mean?
A cyan (blue-green) dot on a pure red background indicates a dead or missing red subpixel at that location. The pixel is producing green and blue but not red, resulting in cyan. This is a 'Type 2' pixel defect. Cyan dots on red are a clear sign of subpixel failure and typically qualify for monitor replacement under warranty if within the manufacturer's defect tolerance policy.
What does color uniformity look like on the red test?
On a healthy monitor, the red screen should look uniformly saturated across the entire panel. Color uniformity issues appear as areas that look more orange (lower blue output), more pink (higher blue output), darker, or less saturated. This is common on budget panels and large displays. Minor edge variation is normal; center-to-corner saturation differences of more than 10% are a significant quality issue.
Does the red test work for OLED vs LCD screens?
Yes, but the interpretation differs. LCD monitors show backlight uniformity effects on red. OLED screens may show slight color shift across the panel on red due to per-pixel variation, but uniformity is typically excellent on OLED. OLED screens are more susceptible to burn-in with static images; avoid leaving the red test on an OLED display for extended periods (over 5 minutes).
Can I fix a missing red subpixel?
A missing or dead red subpixel is unlikely to be fixed with software tools, as the transistor for that subpixel has permanently failed. Pixel-cycling software works best on stuck (always-on) subpixels, not dead (always-off) ones. Hardware repair at the pixel level is not practical for consumer monitors. If the defect is within warranty and exceeds the manufacturer's tolerance, replacement is the standard remedy.
How many red subpixel defects are acceptable?
ISO 13406-2 Class II allows up to 2 permanently dark ('dead') subpixels and up to 5 bright ('stuck') subpixels per million pixels. In practice, most premium monitor warranties offer pixel-perfect policies (zero defects tolerated). Budget monitor policies may allow 3–5 defects total across all test colors before replacing the unit. Always check the specific warranty policy for your monitor model.
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