Free Online Screen Test - Dead Pixel & Display Test

How to Test Your Screen

Preparation

1. Clean Your Screen: Wipe dust and smudges for accurate testing
2. Adjust Lighting: Test in normal room lighting conditions
3. Use Fullscreen: Click fullscreen button for best results
4. Disable Overlays: Close notifications and other windows

Dead Pixel Test

1. Select solid color test (Black, White, Red, Green, Blue)
2. Look carefully at entire screen
3. Dead pixels appear as black dots on colored backgrounds
4. Stuck pixels appear as colored dots on black background
5. Move close to screen for better visibility
6. Test all colors to identify all defective pixels

Color Accuracy Test

1. View primary colors (Red, Green, Blue)
2. Check for color uniformity across screen
3. Look for color shifts or tinting
4. Compare with reference if available
5. Test secondary colors (Cyan, Magenta, Yellow)

Brightness Uniformity Test

1. Display solid gray or white screen
2. Look for bright or dark spots
3. Check corners and edges carefully
4. View from different angles
5. Note any backlight bleeding

Gradient Test

1. Display gradient pattern
2. Check for smooth color transitions
3. Look for banding or posterization
4. Test both horizontal and vertical gradients

Understanding Test Results

Dead Pixels

What they are: Pixels that remain black regardless of displayed color

Cause: Transistor failure, cannot be fixed

Visibility: Most noticeable on bright backgrounds

Action: Check warranty, may qualify for replacement

Stuck Pixels

What they are: Pixels stuck on one color (red, green, or blue)

Cause: Sub-pixel stuck in on position

Visibility: Most noticeable on black or contrasting backgrounds

Action: May be fixable with pixel fixing tools or gentle pressure

Backlight Bleeding

What it is: Light leaking from edges or corners

Cause: Poor panel assembly or pressure on LCD

Visibility: Most noticeable on black screens in dark rooms

Action: Minor bleeding is common, severe cases may warrant return

Color Uniformity Issues

What it is: Color shifts or tinting across screen

Cause: Panel quality, backlight variation

Visibility: Noticeable on solid colors, especially gray

Action: Calibration may help, severe cases indicate defect

Manufacturer Pixel Policies

Type	Typical Policy
Dead Pixels	3-5 dead pixels may be acceptable
Stuck Pixels	Usually covered under warranty
Bright Pixels	Lower tolerance (1-2 pixels)
Pixel Clusters	2+ adjacent pixels usually covered

Tips for Accurate Testing

• Test in fullscreen mode for complete coverage
• View screen from normal viewing distance first
• Move closer to inspect suspicious areas
• Test multiple times to confirm findings
• Take photos of defects for warranty claims
• Test immediately after purchase while return window is open
• Compare with another screen if possible