What defects show on a blue screen?
Dead pixels appear dark; stuck pixels may show wrong colors as bright dots against blue.
Diagnostic · Screen
A pure blue fullscreen activates only blue subpixels — ideal for channel tests and cool-toned ambient lighting.
Cycles white, black, red, green, and blue every 5 seconds. Best in fullscreen. All display tests →
Resolution preset
Reveal subpixel defects and uniformity issues specific to the blue channel.
Blue light can reduce harsh shadows in low-light creative setups.
Use alongside white and grey screens to evaluate color temperature drift.
Blue subpixels often show age-related issues first on some LCD panels — a full blue field makes weak zones visible.
Combine with red and green tests to map which channel causes tint shifts on your display.
Dead pixels appear dark; stuck pixels may show wrong colors as bright dots against blue.
Reduce brightness for long sessions. This tool does not increase emission beyond your panel settings.
Yes — select 4K (3840×2160) and download PNG.
Yes, in browsers that support fullscreen and canvas download.