Green Dead Pixel Test
A green dead pixel test fills your screen with pure green (#00FF00) to detect pixels with a failed green subpixel — appearing as magenta (pink-purple) dots against the green background. Green is also the most sensitive test color for the human eye: we have more green-sensitive cone cells than red or blue, so even minor uniformity issues are more perceptible on green. A perfect green screen should be uniform with no magenta dots, pink patches, or dark bands.
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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What Do Magenta Dots on the Green Screen Test Mean?
| 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 see magenta dots on the green pixel test?
A magenta (pink-purple) dot on a pure green screen indicates a dead or failed green subpixel. The pixel is producing red and blue (which mix to magenta) but not green. This is a clear subpixel defect. Magenta on green is one of the easiest pixel defects to spot because our eyes are particularly sensitive to the green-magenta contrast. Any magenta dot on the green test is a real defect worth noting.
Why is green the most sensitive test color for pixel defects?
Human vision has significantly more green-sensitive (M-cone) receptors than red or blue. We're approximately 3× more sensitive to luminance differences in the green channel. This means defects in green subpixels are more visually disruptive than equivalent defects in red or blue. It also means green uniformity issues (uneven saturation, bands) that are invisible on other colors can be seen clearly on a solid green screen.
What does a dark band on the green screen indicate?
A dark or lighter horizontal or vertical band on the green screen can indicate a 'line defect' — an entire row or column of pixels with an issue. This can affect the gate or source driver circuits in the panel. Line defects are typically considered major defects under all manufacturer warranty policies and almost universally qualify for a free replacement under warranty.
My screen looks slightly yellow-green in some areas — is this normal?
Slight yellow-green variation across the panel indicates color temperature or gamut uniformity issues. Some variation is normal for all panels, especially near edges. If the center and corners differ visibly, the panel has significant color uniformity variance. This is more common on lower-cost IPS and TN panels. It's generally acceptable unless it's visually distracting during normal use (photo editing, video work).
Should I test green before or after red and blue?
The order doesn't matter for accuracy — each color tests different subpixels independently. However, testing green last (after black, white, red, blue) is a good practice because green is the most visually demanding. Your eyes may be less sensitive to green uniformity issues after looking at other colors first. Testing green when your eyes are fresh gives you the most accurate perception of any uniformity problems.
Does a failing green subpixel affect gaming or content creation?
A single missing green subpixel is only disruptive if it's in a visible screen area. For gaming, it's usually tolerable unless it falls on a HUD element or central area. For color-critical work (photo editing, video grading), even one subpixel defect is considered unacceptable as it can throw off color perception in that area. Professional creative users should insist on pixel-perfect screens.
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