Dead pixel test

Nine full screen colours in sequence, which is the only reliable way to find a bad pixel.

Escape or one tap comes back.

Every colour, one tap away

Brightness, timer and colour cycle

Why one white screen is not a dead pixel test

Each pixel on your display is three subpixels: red, green and blue. A white screen lights all three at once, so a pixel with a single failed subpixel still looks very nearly white and you will scroll straight past it. Only a screen that lights one channel at a time isolates the fault. That is why this test cycles through white, black and every primary and secondary in turn rather than showing you one colour and calling it done.

How to run it

  • Clean the screen first. Almost every "dead pixel" reported to a manufacturer turns out to be dust.
  • Set the cycle speed to 1.5 or 3 seconds and press Run cycle. It goes full screen and steps through nine colours.
  • Sit at your normal working distance and scan the screen in horizontal strips rather than trying to take it all in at once.
  • Note where anything odd is, then use the arrow keys to step back to that colour and look again.

Telling dead from stuck

A dead pixel receives no power. It is black on every single colour including white, and no software will ever fix it. A stuck pixel is permanently on in one or more subpixels: it stays red, green, blue, cyan, magenta, yellow or white on every screen, including black. Stuck pixels are the hopeful case, because rapid colour flashing frees them often enough to be worth twenty minutes of trying.

There is a third thing people find here that is neither. A blurred bright patch, rather than a sharp dot, that stays in place on every colour is pressure damage to the layers behind the panel. It is physical, it is permanent, and it usually came from closing a laptop lid on something.

What manufacturers will actually replace

Nearly every display manufacturer publishes a dead pixel policy, and nearly all of them allow some number of faulty pixels before a panel counts as defective. The thresholds differ by brand, by panel size and by whether the unit is sold as a professional product, and a single dead pixel on a consumer monitor is very often within spec. It is worth reading the policy for your specific model before starting a return, and worth running this test on day one rather than in month eleven, because a fault found inside the return window is a far simpler conversation than a warranty claim.

Frequently asked questions

How long should a dead pixel test take?

Under a minute at 1.5 seconds per colour. What matters is scanning the panel in strips rather than trying to take it all in at once, and stepping back to any colour where something looked odd.

Can dead pixels appear over time?

Yes. Pixels fail throughout a panel's life, not only at manufacture, which is why it is worth testing a new display on day one and keeping the result in mind. A fault found inside the retailer's return window is a return rather than a warranty claim.

How many dead pixels are acceptable?

That depends entirely on the manufacturer, the panel size and whether the product is sold as a professional item. Most publish a pixel defect policy allowing some number before a panel counts as defective, and a single defect on a consumer monitor is very often within specification. Read the policy for your model before starting a claim.

Is a dead pixel the same as a bright dot?

No. A dead pixel is black on every colour because it receives no power. A bright dot is a pixel stuck on, which shows as a coloured or white point on every screen including black. Only the second one is worth trying to fix.