UtilityBaseScreen Tools
Red Screen
Fill your display with solid red to test the red subpixels.
Updated January 6, 2026
How to use the red screen
- 1Click the color area or the fullscreen button to enter fullscreen.
- 2Move the mouse or tap the screen to show or hide the toolbar.
- 3Use the brightness slider to dim the color if it is too intense.
- 4Press Esc or the exit button to leave fullscreen.
Common uses
- Isolate faulty red subpixels during a pixel inspection.
- Use dimmed red light to preserve night vision.
- Test color uniformity across the panel.
Frequently asked questions
How do I make my whole screen red?
Open the tool and press the fullscreen button (or the F key). The entire display turns red. Press Esc or F again to exit fullscreen.
Can I adjust the brightness?
Yes. Use the brightness slider in the toolbar to dim the screen without changing your system settings. This is a software dimmer applied on top of the color.
Will my screen turn off while the color is displayed?
The tool requests a screen wake lock in browsers that support it, which prevents the display from sleeping while the tool is active. If your browser doesn't support wake locks, adjust your system sleep settings for long sessions.
Does this work on phones and tablets?
Yes. On mobile, tap the fullscreen button to hide the browser interface where the platform allows it. Tap anywhere on the screen to bring the controls back.
About this tool
The red screen tool fills the display with pure red (#FF0000), lighting only the red subpixel of every pixel on the panel. If any pixel's red subpixel is dead, it appears as a dark dot against the red field; if a different subpixel is stuck on, it shows as an off-color dot. Cycling through red, green, and blue screens is the standard way to isolate which subpixel is faulty. Red light is also the least disruptive to night vision, so a dimmed red screen doubles as a darkroom-friendly light.
Like everything on UtilityBase, the red screen runs entirely in your browser — nothing you enter is uploaded or stored on a server. It's free to use with no account required. Browse more screen tools here.
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