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Phone Screen Test - Dead Pixels & Colour Check
Open this page on your phone and tap a colour. Look closely at each screen for specks, lines or uneven areas. This guide uses our free dead pixel test.
Pick a colour, or start the full-screen cycle. Look for dots that stay a different colour from the rest of the screen.
In full screen: click or press Space for the next colour, Esc to exit.
What each colour reveals
- Black: shows stuck bright pixels and backlight bleed on LCD screens.
- White: shows dead pixels, dirt and yellow or pink tint.
- Red, green, blue: shows sub-pixel faults, which look like a coloured dot on one colour only.
- Every colour in turn: uneven patches, banding or a faint ghost image from burn-in show up most clearly when you flip quickly between colours.
OLED vs LCD
OLED phones, such as most iPhones since the X and many Samsung and Pixel models, can show ghost images or burn-in when the same content has been on screen for a long time. LCD phones can show light leaking from the edges on black. A little unevenness at very low brightness can be normal on some OLED panels.
Buying or returning a phone?
Do this test in the shop or on the day of delivery. Take a clear photo of any fault so you can show it for a return or warranty claim.
Last updated: 2026-10-04
Frequently asked questions
Can I fix a stuck pixel on my phone?
A stuck pixel sometimes recovers after cycling colours for several minutes. A dead pixel is a hardware fault and normally needs a screen replacement.
Will this test damage my screen?
No. It just shows solid colours, the same as any wallpaper.