Dead Pixel Test — Inspect Every Pixel On Your Screen
Full-screen solid colours let you spot dead pixels (always black), stuck pixels (always one colour) and hot pixels (always bright). Works on any monitor, laptop, phone or TV. Test before your return window closes.
How to test for dead pixels:
- Click each colour above to open it full-screen.
- Inspect your whole panel from a comfortable distance.
- Look for any dot that stays the wrong colour (dead = black, stuck = coloured).
- Use ← → to switch colours, Esc to exit.
How to find dead pixels (and tell them apart from dust)
Every pixel on an LCD or OLED screen is made of three sub-pixels — red, green and blue. Each sub-pixel is driven by its own microscopic transistor. When a transistor fails, the sub-pixel stops responding and you get a pixel that is stuck at one brightness forever. The pattern of failure tells you which kind of defect you have:
| Defect | What it looks like | Cause | Fixable? |
|---|---|---|---|
| Dead pixel | Black dot on every colour | Transistor failed — no light passes through | No. RMA the monitor if under warranty. |
| Stuck pixel (one colour) | Always red, green or blue | One sub-pixel transistor stuck ON | Sometimes. Try pixel massage or flashing-colour tools. |
| Stuck pixel (white) | Always white on dark backgrounds | All three sub-pixels stuck ON | Sometimes. Same fix as coloured stuck pixels. |
| Hot pixel | Bright spot on long exposures (mostly a camera issue) | Sensor leak; rare on monitors | Usually not on monitors. |
| Dust under glass | Tiny dark speck that does not change colour | Particle between panel and glass | Sometimes — a service centre can clean it. Do not open the panel yourself. |
The five colours you must test
A single colour is not enough. Different defects reveal themselves on different backgrounds. Here is the minimum test sequence:
- White — Reveals dead pixels (they appear as black dots against the white background).
- Black — Reveals stuck pixels (they appear as bright coloured dots against the black background).
- Red, green and blue — Each sub-pixel colour in isolation. A stuck sub-pixel shows up as the wrong colour on its own background.
- Grey — Reveals uniformity issues and pressure marks that are invisible on pure colours.
What to do if you find dead pixels
If the monitor is new and within the return window, the simplest option is to return it for a replacement — most retailers accept returns for any reason within 14-30 days. If you are outside the return window but within the manufacturer's warranty, check the manufacturer's dead-pixel policy. The ISO 9241-307 standard defines acceptable defect counts by class, and most manufacturers publish their own policy based on this standard.
For stuck pixels, try the pixel massage technique before RMA: turn off the monitor, place a soft cloth over the stuck pixel, and apply very gentle pressure with your fingertip for 5-10 seconds. Turn the monitor back on while still pressing. This can sometimes unstick the transistor. There are also websites that flash rapidly cycling colours at the screen for 10-30 minutes, which can also unstick pixels. Neither method is guaranteed and both carry a small risk of making things worse — proceed at your own risk.
Frequently asked questions
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