How to use the pixel test
- Go fullscreen: Click the fullscreen button so the color covers your whole display.
- Cycle the colors: Click anywhere on the test (or press Enter or Space) to switch between solid red, green, and blue.
- Inspect slowly: Look over the whole screen on each color, including the corners and edges. A magnifying glass or your phone's camera zoom can help on high-resolution screens.
- Clean first: Wipe the screen with a soft cloth before you start. Specks of dust can look a lot like dead pixels.
- Extra modes: 'Continuous' cycles the colors automatically at the speed you set, and 'Per Pixel' fills the screen with random colored noise instead of one solid color. Continuous mode flashes quickly, so read the warning before enabling it.
Understanding pixel issues
- Dead pixel: A pixel that stays black on every color. This is usually a permanent hardware defect where the pixel's transistor no longer works.
- Stuck pixel: A pixel stuck on one color, such as always red, green, or blue. It's easiest to see on the colors it doesn't match: a pixel stuck on red stands out on the green and blue screens. These can sometimes be fixed.
- Lit (hot) pixel: A pixel that is always fully on, showing as a bright white dot on every color. This is also typically a hardware defect.
- Pixel clusters: Several faulty pixels close together. These are more noticeable and more likely to be covered by a warranty.
While you're looking, also watch for patches, clouding, or uneven brightness across a solid color. That points to backlight or panel uniformity problems rather than individual pixels.
What a working screen looks like
- Working device: Each color fills the screen evenly, with no dots of a different color and no black or white specks.
- Malfunctioning device: Tiny black dots (dead), colored dots (stuck), or white dots (lit) that stay in the same place as you cycle through the colors.
What To Do About Pixel Issues
Dead or lit pixels
- Hardware defect: These are generally permanent and can't be fixed with software.
- Warranty: If your device is new or under warranty, check the manufacturer's dead pixel policy. Many manufacturers require a minimum number or a particular location of faulty pixels before they will replace the screen.
- Acceptance: If you're out of warranty or below the manufacturer's threshold, you may have to live with them.
Stuck pixels
- Pixel-fixing flashing: Rapidly flashing colors over a stuck pixel can sometimes unstick it. Turning on both 'Continuous' and 'Per Pixel' flashes random colors across every pixel. Run it for a few minutes at a time, look away from the screen while it runs, and don't use it if you're sensitive to flashing lights.
- Gentle pressure (risky): Some people report success gently massaging the spot with a soft cloth wrapped around a stylus tip. This can damage the screen if done wrong, so proceed at your own risk.
- No guarantee: Success isn't guaranteed. If a stuck pixel won't budge, treat it like a dead pixel for warranty purposes.
The color doesn't look perfectly even
- Lighting and angle: Room lighting, reflections, and viewing angle can make a solid color look uneven. View the screen straight on in a dim room.
- Brightness: Use your normal brightness setting. Very low brightness hides problems; very high brightness exaggerates backlight bleed.
- Compare: Check the same area on each color, and compare with another display if you can.
Use this test to carefully inspect your screen. It's a valuable check for new displays and for diagnosing screen anomalies.
Frequently asked questions
Why red, green, and blue instead of just white?
Every pixel is made of red, green, and blue subpixels. Showing one color at a time makes a stuck or dead subpixel stand out, where it could hide on a white screen.
Does this find every screen defect?
It's a quick, practical check for dead, stuck, and lit pixels and obvious uniformity problems. It doesn't replace a full panel diagnostic or calibration tool.
Is the continuous mode safe?
It flashes bright colors quickly and may trigger seizures in people with photosensitive epilepsy. That's why it shows a warning first. Stop immediately if you feel unwell.