Dead Pixel Test

Before you start

• Clean the screen: Dust and fingerprints are easy to mistake for dead pixels. Wipe the screen gently with a dry microfiber cloth first.
• Turn off the lights or close the curtains: The darker the room, the easier it is to see bright pixels and bleed. Always turn off the lights for the black screen.
• Turn brightness all the way up: Dead pixels and uneven brightness are easier to find at high brightness. A web page can't change the backlight, so adjust it in your device settings.
• Sit about an arm's length away: Look at the whole screen from your usual distance first, then move in closer to anything suspicious.

Bright, dead, and stuck pixels: what's the difference?

On most screens, each pixel is made of red, green, and blue subpixels. Different failures look different:

• Bright pixel: A pixel that's always on. It's most obvious on black, where it looks like a tiny star.
• Dead pixel: A pixel that never lights up. On white or another bright color it looks like a small black dot.
• Stuck pixel: A pixel stuck on one color, usually red, green, or blue. It jumps out when you switch to the other solid colors.

Not sure if it's a dead pixel or dust? Wipe the screen first. If it wipes away, it was dust. If it stays in the same place on every color, it's a pixel.

How to check for backlight bleed and burn-in

• Backlight bleed: Turn off the lights, open step 2 (black), and look at the four corners and along the edges for patches of light. LCDs are lit from behind, so a faint glow at the corners is common. What matters is how large it is and whether you notice it right away. OLED screens have no backlight and black areas give off no light, so they don't have backlight bleed.
• Burn-in: Open step 6 (gray 25%) or step 7 (gray 50%) and look for traces of earlier content, such as a taskbar, a TV channel logo, or a game HUD. OLED screens are more prone to burn-in. Image retention on an LCD is usually temporary and often fades after showing something else for a while.
• Color banding: The gray ramp in step 9 should change smoothly from black to white. Visible bands can come from the screen, the graphics card, or color settings. They're not dead pixels.

Found a dead pixel? What to do next

• Take photos and note where it is: Take one photo of the whole screen and one close-up with your phone. Note which test pattern showed it and roughly which corner it's in.
• Check the return window: Online and in-store return periods are limited, so test as early as you can, ideally the day you get the screen.
• Look up the manufacturer's dead pixel policy and warranty: How many dead pixels count as a defect varies by brand and model, and some policies also look at whether they're in the center or near the edge. Go by what the manufacturer's website or warranty says.
• Include details when you contact support: Send the photos, model, serial number, and purchase date together to speed things up.