Dead Pixel Test

How to use it

1. Clean the screen so that you do not mistake dust for a defect.
2. Start the test. It opens in full screen.
3. Click through the colours and look closely at each one.

Good to know

A dead pixel stays black on every colour. A stuck pixel stays one bright colour, and these sometimes recover after running flashing video over the spot for a while.

Manufacturers have different rules on how many bad pixels justify a replacement, so check the warranty.

What you might see

Testing carefully

• Set brightness high and dim the room.
• The test shows black, white, red, green, blue, cyan, magenta and yellow.
• Click, or press the right arrow or space, to go forward. Use the left arrow to go back and Esc to leave.
• Scan in strips from top to bottom, close to the screen.
• On an iPhone, Safari may keep its bars on screen, since it limits full screen mode for web pages.

If you find one

Photograph it on the solid colour, along with the date and the device serial number. Many manufacturers only replace panels above a set number of defects, so read the warranty and act within the store's return period. Never press hard on a screen to fix a pixel, as this can cause more damage.

Questions