Check any screen for dead and stuck pixels. This test cycles your whole display through solid red, green, blue, white and black — faulty pixels show up as dots that don't match. Works on any monitor, laptop, phone or TV.
Press start to fill the screen and auto-cycle the test colors. Use Pause to hold a color, the arrow keys to step through by hand, and Esc to exit. Look closely at each color for dots that stand out.
The idea is simple: fill the screen with one flat color at a time so any pixel that behaves differently gives itself away.
Start the test and let it move through red, green, blue, white and black. Clean your screen first so dust isn't mistaken for a fault.
A dead pixel stays black on every color, including white. A stuck pixel keeps showing red, green or blue when the background is a different color. Pause on a color to inspect an area.
Leave the colors cycling over the spot for a while, or gently massage it with a soft cloth while the screen is on. Stuck pixels sometimes recover; a truly dead one usually won't.