How to Check for Dead Pixels
A dead pixel test is an essential diagnostic step when purchasing a new monitor, laptop, or TV. Modern displays are composed of millions of tiny pixels. For example, a standard 4K monitor has over 8.2 million pixels. With such a high density, manufacturing defects can occasionally result in a few pixels that fail to function correctly.
Dead Pixels vs. Stuck Pixels
It is important to distinguish between the two main types of pixel defects:
- Dead Pixels: These pixels receive no power and remain permanently black. They are easiest to spot against a solid white or bright background. Unfortunately, true dead pixels are usually a permanent hardware failure and cannot be fixed.
- Stuck Pixels: These pixels are stuck in the "on" position, constantly displaying a single sub-pixel color (usually red, green, or blue). They are most visible against a black background. Unlike dead pixels, stuck pixels can sometimes be revived.
How to Use This Tool
To thoroughly test your display, you need to examine it displaying pure, solid colors. Follow these steps:
- Clean your monitor screen gently with a microfiber cloth. Dust particles can easily be mistaken for dead pixels.
- Click the "Start Fullscreen Test" button above.
- Carefully scan the entire screen, looking for any tiny dots that stand out from the background color.
- Click anywhere on the screen to cycle through White, Black, Red, Green, and Blue backgrounds. You must test all colors to ensure all sub-pixels are functioning.
What to do if you find a defect?
If you discover a stuck pixel, you can try gently massaging the area with a soft cloth (be very careful not to press too hard and cause further damage). There are also software tools that rapidly flash colors in an attempt to "unstick" the pixel.
If you find a dead pixel on a newly purchased monitor, check the manufacturer's warranty policy. Most brands have a "dead pixel policy" that dictates how many defective pixels warrant a replacement. Once you've verified your panel is pristine, make sure you are getting the smoothest performance by checking your Refresh Rate (Hz) and running our Screen Tearing Test.