Test the red subpixels
A solid red field helps reveal uneven color, dark pixels, and screen tinting.
Free online display tool
Red Screen
Open a pure red screen for RGB pixel checks, low-light visibility, creative lighting, or a bold background without installing an app.
No sign-upRuns privatelyWorks on every device
Tap twice or swipe down to exit
Press F
Useful by design
What can you do with a red screen?
One plain color can be surprisingly handy. Here are a few practical ways to use it.
Protect low-light vision
Dim red light is commonly used when you need visibility without a harsh white screen.
Add warm creative light
Use a nearby display as a simple red accent for photos, video, or streaming.
Three quick steps
How to use this full-screen tool
- 1
Choose your color
Use the default red or pick a precise custom shade.
- 2
Open full screen
Tap the main button or press F. iPhone users get an automatic browser-safe fallback.
- 3
Exit when finished
Press Escape, double-tap, or swipe down. Nothing is stored or uploaded.
More colors
Switch the mood in one click
Good to know
Frequently asked questions
What is a red screen test?+
It fills the display with red so you can visually inspect color uniformity and pixels.
How do I exit full screen?+
Tap the screen, swipe down on the iPhone fallback, or press Escape on a keyboard.
Is red light easier at night?+
Many people find dim red light less disruptive than bright white light, but comfort varies.
Can I download a red background?+
Yes. Choose a preset or custom size and create a PNG directly in your browser.
Need a background file?
Choose a resolution above and create a clean PNG in seconds.