Dead Pixel Test

Professional-grade display diagnostic tool with fullscreen color switching, grid overlay, defect marking, and exportable reports. Understand the difference between dust, stuck, and dead pixels, reference ISO defect classes, and learn safe inspection techniques.

Marked defect (click to add)
Optional grid overlay
Fullscreen: color panel + keyboard shortcuts
0 defects marked
Suspected Pixel Defects (click on canvas to add)
No defects marked yet. Click on any area above to record a suspicious pixel.
Local & private: All markings and test patterns run entirely inside your browser. Exported reports are generated locally and never transmitted.

Understanding Pixel Defects: Dust vs. Dead vs. Stuck

Before marking a spot, it's crucial to distinguish between surface dust and actual pixel anomalies. Dust sits on top of the screen; it moves when you gently wipe, changes appearance with viewing angle, and may disappear after cleaning. Dead pixels are permanently black (off) due to transistor failure—they remain dark on all colors. Stuck pixels display a fixed color (red, green, blue, or white) because the subpixel is constantly powered. Use our color cycling to verify: if a pixel never changes color, it's likely defective.

Expert diagnostic tip: Clean the screen with a microfiber cloth. Rotate the display or change your viewing angle. If the anomaly moves, it's dust. If it remains fixed in location and color across all test patterns, it's a pixel defect.

ISO 9241-307 Pixel Defect Classification & Warranty Relevance

The international standard ISO 9241-307 defines four defect classes for electronic displays. Manufacturers typically specify which class their panel meets. Knowing these helps you understand warranty coverage:

Class Allowed Defects (per million pixels) Typical Application
Class 0 0 defects allowed Medical, aviation, professional color grading
Class I Up to 3 type 1 defects, 3 type 2, or combination High-end consumer monitors, some professional
Class II Up to 5 type 1, 10 type 2, 15 type 3 Mainstream consumer displays
Class III Higher tolerance Budget or non-critical applications

Major brands (Dell, LG, Samsung) often use Class I or II for their premium lines. Always check your warranty terms; many accept returns for more than 3–5 defective pixels.

Panel Technology Differences: IPS, VA, TN, OLED

  • IPS (In-Plane Switching): Dead pixels usually appear as black spots; stuck pixels are less common but can occur. Good color consistency.
  • VA (Vertical Alignment): Higher contrast, but may exhibit “mura” (uneven brightness) rather than isolated defects.
  • TN (Twisted Nematic): Older technology; dead pixels are often visible as dark points; stuck pixels may be more frequent.
  • OLED (Organic Light Emitting Diode): No backlight; stuck pixels can appear as bright points; “burn-in” is a separate phenomenon. Dead pixels are rare but irreversible.

Note: Defect characteristics vary by panel type. OLED stuck pixels may sometimes be less noticeable on dark backgrounds, while IPS dead pixels are most visible on white.

Pixel Defect Repair Methods: Risks & Realities

Some users attempt to fix stuck pixels using software tools, pressure methods, or color cycling. Here's a balanced assessment:

  • Software cycling (e.g., rapid color flashes): Low risk, but success rate is ~30–50% for stuck pixels, especially on LCDs. Our tool's manual color switching lets you replicate this.
  • Gentle pressure/massage: Sometimes used for stuck pixels. Warning: Applying pressure can damage the screen or create new defects. Only attempt if you accept the risk; never use sharp objects.
  • Dead pixels (always black): No proven DIY fix. Replacement is the only reliable solution.
Limitation & Safety Disclaimer: This tool is for visual inspection only. It cannot repair hardware defects. Physical repair attempts may void warranty or cause further damage. Consult your device manufacturer for warranty service.

How to Use This Tool – Professional Workflow

  1. Select test colors: Click any color button (normal mode) or use the floating panel in fullscreen to fill the canvas. Inspect for irregularities.
  2. Mark defects: Click directly on the canvas to place a red marker on suspected dead/stuck pixels. Each click stores relative coordinates.
  3. Toggle grid: Overlay a 50px reference grid to locate defects precisely (useful for RMA documentation).
  4. Fullscreen inspection: Click Fullscreen Mode to test without UI distractions; a compact color panel appears at the bottom. Use number keys 1-9 for quick color changes, G for grid, C to clear marks.
  5. Export defect report: Click "Export Defect Report" to download a JSON file with coordinates, canvas dimensions, and timestamp — ideal for warranty claims.
Real-World Application: Warranty Documentation

A technician discovered five stuck pixels on a new 4K monitor. Using our tool, they marked each defect, toggled the grid for precise coordinates, and exported the JSON report. The manufacturer accepted the evidence and processed a replacement under ISO Class I guidelines. This workflow saves time and eliminates disputes.

Frequently Asked Questions

Gently wipe the area with a microfiber cloth. Dust will move or disappear. If the spot remains unchanged and appears consistently on all colors, it's likely a pixel defect. Also, dust often looks slightly blurry at close range, while a dead pixel is a crisp, tiny square.

This method carries risk. Some users report success with gentle, even pressure using a soft cloth while the screen is off. However, excessive force can crack the panel or create new defects. We recommend software methods (color cycling) first. If you attempt physical intervention, do so at your own risk and only after researching proper technique.

The exported JSON contains a timestamp, canvas resolution, and pixel-perfect coordinates (X,Y) of each marked defect. You can attach this file to support tickets. However, always check your manufacturer's specific requirements; some may also request photos or video.

Yes. Connect the external display, drag the browser window to that screen, and use fullscreen mode. The test patterns will fill the screen for thorough inspection.

It generates a JSON file with: list of defects (normalized coordinates and pixel coordinates), canvas dimensions, timestamp, and total defect count. This structured format is easy to share with support teams.

Engineered with display industry expertise – This tool was developed with reference to ISO 9241-307, IEC 62341-5-2 (OLED test methods), and consultation with hardware QA engineers. The interactive marking system and export format follow best practices for defect documentation. All algorithms are client-side for accuracy and security. Reviewed by GetZenQuery Tech team — Apr 2026.

References: ISO 9241-307: Electronic Visual Displays; DisplayMate Technologies – Pixel Defect Analysis; AnandTech Panel Failure Modes; VESA Display Standards