White Screen

How to use the white screen

1. Press Open full white screen. The whole screen turns white and the mouse pointer hides after a moment.
2. Pick a shade before or during the test: pure white, lighter grays, or a warm or cool white for a softer light.
3. Set Auto close if you are using the screen as a lamp, so it turns off on its own.
4. Press Esc, or tap the screen on a phone, to come back to this page.

What the results mean

A healthy screen shows one even sheet of white from corner to corner. Things to look for:

• Dark or black dots are dead pixels. Confirm them with the dead pixel test, which cycles other colors too.
• Darker corners or edges on an LCD are normal to a small degree (vignetting). A strong difference points to a weak backlight.
• Yellow or pink patches are uneven backlight or panel aging. Compare at 50% gray, where tints show most clearly.
• Dust and fingerprints stand out against white, which is why cleaning with the white screen on works so well. Switch to the black screen to see greasy smudges instead.

What a white screen is used for

Light source. A laptop or monitor at full brightness makes a soft, flattering fill light for video calls, selfies and product photos. Use the warm white shade for skin tones and the cool white to match daylight. Phones make a handy reading light or a torch that does not blind.

Cleaning. Dust, hair and streaks are nearly invisible on a dark desktop but obvious on white. Open the white screen, wipe with a dry microfiber cloth, and check again.

Display checks. White reveals dead pixels, backlight unevenness and color tints. Open the same page on two monitors to compare their white point: one will usually look warmer than the other, and you can adjust its color temperature to match.

Tracing and scanning. Put a sheet of paper on a bright white tablet to trace a drawing, or use a white phone screen as a backlight for negatives and slides.

Common problems and fixes

The white looks gray or dim

Raise the screen brightness to 100%, turn off night mode, blue light filters and auto brightness, and disable any "eco" or "power saver" display setting. On Windows, also check HDR is off for SDR content.

One side is yellower than the other

Backlight unevenness is common on cheap or old LCDs and cannot be fixed in software. If the monitor is new, it may be covered by warranty; take a photo of the 50% gray screen as evidence.

Full screen does not work on my iPhone

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