Green Screen

How to use the green screen

1. Press Open full green screen. The whole screen turns green and the mouse pointer hides after a moment.
2. For a pixel check, stay on Pure green at full brightness and look across the panel from about 30-50 cm away.
3. For a backdrop, choose Chroma key green, place the object in front of the screen and light the object, not the screen.
4. Press Esc, or tap the screen on a phone, to come back to this page.

What the results mean

Pure green (#00FF00) lights only the green subpixel of each pixel. Your eyes are most sensitive to green, so a green screen is the clearest single-colour test for brightness differences. A healthy panel shows one even green everywhere. Look for:

• A black dot: the green subpixel there is dead. If it is also black on the white screen, the whole pixel is dead.
• A red, blue or white dot: a red or blue subpixel is stuck on. Try the stuck pixel fixer.
• Yellowish or bluish patches: the panel shifts colour across its surface. Darker edges are normal in small amounts on LCDs.

Check the red and blue screens as well to cover every subpixel, or run the dead pixel test for all colours in sequence.

What a green screen is used for

Pixel and uniformity checks. Green carries most of the brightness your eyes see, so a full green screen makes backlight bleed, dark corners and banding easy to spot. It is also one of the three single-channel tests every new display should pass.

Small chroma key backdrop. Looking for a green screen for video editing? A monitor or tablet showing chroma key green (#00B140) works as a backdrop for close-up product shots, jewellery or a small figure, and editing software can key it out. Light the subject separately and turn the screen brightness down so green does not spill onto the edges. A person-sized green screen still needs fabric or paint, because a monitor is too small and too glossy for that.

Calm light and signals. A green screen makes a soft ambient light, an "available" or "come in" sign, or a "go" signal for games and timers.

Common problems and fixes

The green looks yellow or too bright

Set the monitor to its standard or sRGB mode and turn off night mode and blue light filters. Wide-gamut monitors in vivid mode show a very saturated, almost neon green; that is the panel, not a fault.

The chroma key will not cut out cleanly

Lower the screen brightness, angle the screen so it does not reflect lights, keep the subject a little in front of it, and use chroma key green instead of pure green. Glossy screens reflect the subject, which leaves green fringes.

Full screen does not work on my iPhone

iPhone Safari does not allow websites to go fully full screen, so the green fills the browser window instead. Rotate to landscape or add the page to your home screen.