How to use it
- Press “Full screen” or tap the black area.
- Clean the screen, check for light bleed or simply leave it on. The arrow keys switch to other test colors.
- Double-click, double-tap or press Esc to exit.
Questions and answers
Does a black screen save battery?
On OLED and AMOLED screens (most recent phones and some laptops) black pixels are switched off, so a black screen uses very little power. On LCD screens the backlight stays on, so the saving is small.
Can I clean the screen while it is open?
Yes. Single taps do nothing in full screen, so you can wipe a touch screen; only a double tap or Esc closes it. The black background makes dust and smudges easy to see.
Will the screen turn off by itself?
With “Keep the screen on” ticked, browsers that support it (recent Chrome, Edge and Safari) keep the display awake while the black screen is open in full screen.
How do I check for dead pixels?
Go full screen and press the arrow keys to cycle through black, white, red, green and blue. A dead pixel stays dark on every color; a stuck pixel stays one bright color. Look closely, section by section.