Use guide

Dead pixel test — fullscreen solid colors

Check for dead or stuck pixels with solid red, green, blue, white, and black fullscreen fields.

Steps

Open Instant White and tap Open this preset (solid red).
Go fullscreen if the browser allows, then look slowly across the panel.
Cycle colors in the controls: green, blue, white, then black.
Note pixels that stay dark (dead) or stuck on one color. Re-test after a power cycle if unsure.

Stuck pixels sometimes change when you cycle colors; dead pixels stay black.
Direct color links: /?c=red&b=100&f=1&w=1 — change c= to green, blue, white, or black.
View from a normal distance first, then closer for tiny defects.

This is a visual inspection aid, not a repair or warranty tool.
Avoid leaving a max-brightness static color on an OLED panel for hours; it can contribute to burn-in.
The f=1 query asks the page to enter fullscreen. Browsers typically allow Fullscreen API only after a user gesture (tap or click). The request can be denied, and iOS Safari often ignores programmatic fullscreen.
The w=1 query asks for the Screen Wake Lock API so the display stays on. It requires a visible document, usually HTTPS, and is missing or unreliable in some browsers (notably many iOS Safari versions). The screen can still sleep if the OS, battery saver, or the browser refuses the lock.

Part of Instant White — free fullscreen white screen & solid color light tool.