About the Black Screen
A flat black rectangle is the quickest way to catch pixels that are stuck bright on an LCD or OLED panel. Anything that is not black once the panel fills the display is a stuck pixel, a speck of dust or a smear on the glass, and telling those apart takes a wipe with a dry cloth and a change of viewing angle.
The shade selector does more than it looks. Pure #000000 switches OLED pixels right off, which is what you want when judging true black or looking for burn in. A near black such as #0a0a0a keeps every pixel faintly lit, so a pixel that stays completely dark stands out as dead rather than merely switched off. The brightness figure applies a CSS filter to the panel, handy when you need a dim backdrop for a photograph without reaching for the monitor menu.
Everything happens in the tab: the page paints one coloured box and asks the browser for full screen, and Escape brings the toolbar back. When you are grading a panel properly, follow this with the white screen for dust and clouding, then the red screen to inspect a single sub-pixel channel. If you want the exact value in another notation, the hex to RGB converter will translate the code printed under the panel.
How to use
- Choose a shade, then press Go full screen or double click the panel.
- Wait a few seconds for the backlight to settle and the room lights to stop reflecting.
- Sweep your eyes across the surface looking for bright dots, patches or streaks.
- Press Esc to come back, then try another shade to confirm what you saw.
Common questions
- How do I tell a stuck pixel from a speck of dust?
- Dust shifts or disappears when you wipe the glass with a dry cloth. A stuck pixel stays in the same spot and keeps the same colour whatever you do.
- Does showing black save battery?
- On OLED and AMOLED panels it does, because black pixels are switched off entirely. On an LCD the backlight keeps burning, so the saving is negligible.
- Why does my laptop screen glow at the edges?
- That is backlight bleed. LCD panels light the whole sheet from behind and the light leaks unevenly around the frame, which is normal in small amounts.
- Can I use this to clean my monitor?
- Yes, a dark surface makes smudges and fingerprints far easier to see than a bright desktop, so it is a good background while you wipe the panel down.