What can you use a red screen for?
- Preserve night vision for stargazing, astronomy and dark-room work.
- Test for stuck or dead red sub-pixels on your monitor.
- Use as a darkroom-style safelight when viewing on a dim screen.
- Set up a red warning or alert background for events.
- Calibrate red color balance on TVs and monitors.
How to use this red screen
- Click the screen (or press F) to enter true fullscreen — toolbars and tabs disappear.
- Enable Keep Awake if you want the screen to stay on for hours (perfect for a red screen for 10 hours overnight).
- Adjust brightness with the slider — useful for dim rooms or OLED panels.
- Pick any custom color with the color picker, or jump to another preset below.
- Press Esc any time to exit.
Frequently asked questions
Why does red light preserve night vision?
Human rod cells, responsible for low-light vision, are far less sensitive to red wavelengths. A dim red screen lets you read or work without resetting your dark adaptation.
How do I make the red screen full screen?
Click Fullscreen (or press F). Press Esc to exit.