What this test can tell you
The page draws a solid color for you to inspect visually. Compare more than one background and distinguish a mark fixed to the display from something that moves with page content.
It does not automatically detect defects, measure color accuracy or repair a panel. Browser fullscreen, color settings, brightness and room reflections affect what you see.
How to use it
- Press “Open fullscreen” or F.
- Lower the brightness for night use.
- Press Esc or tap to exit.
Testing red subpixels
Compare a persistent dark or differently colored dot on red with the same location on green, blue, white and black. The pattern helps describe the mark but does not establish its physical cause.
Not working? Try these fixes
The red looks orange
Night mode or a warm color profile shifts colors. Turn it off for pure red.
Frequently asked questions
Can I use this red screen as a photographic safelight?
Do not assume a screen is safe for photographic paper or film. Use the materials manufacturer’s specified safelight and testing instructions. The color code alone cannot establish compatibility.
What is the color code?
#FF0000, RGB(255, 0, 0).