Brightness 100%

Red Screen background

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Custom Color
Opens one color window per detected screen. Drag & fullscreen each.

Screen Testing Tools

Auto Color Cycle

Rapidly cycle through colors to help fix stuck pixels. Run for 20–30 minutes for best results.

OLED Burn-in Test

Display a moving pattern to detect and reduce OLED burn-in artifacts on your screen.

Gradient Smoothness Test

Display smooth gradients to check for color banding and bit-depth issues on your monitor.

Checkerboard Pattern Test

Display pixel-level checkerboard patterns to test monitor sharpness and pixel response.

Pixel Response Time Test

Flash rapid black/white transitions to evaluate pixel response time and ghosting.

Viewing Angle Test

Display color bands to help evaluate your monitor's viewing angle consistency.

Gray Uniformity Test

Display 50% gray to reveal backlight hotspots, clouding, and brightness non-uniformity.

Color Accuracy Checker

Display reference color swatches to compare against known standards for calibration checks.

Timer Mode

Set a timer for fullscreen display. Useful for timed screen tests and ambient lighting sessions.

Multi-Monitor Detection

Detect connected displays and open fullscreen color on all screens simultaneously.

Drag each window to a different monitor, then click Go Fullscreen inside it.

About Red Screen

A red screen isolates the red sub-pixel channel of your display, making it invaluable for thorough pixel testing. Each pixel on your monitor is composed of red, green, and blue sub-pixels. By displaying pure red, you can identify sub-pixel defects that might be invisible on a white or multi-color screen.\n\nRed screens are also popular for ambient lighting. The warm, low-wavelength red light is less disruptive to night vision and circadian rhythms compared to blue or white light. Astronomers use red screens on tablets to preserve dark adaptation while checking star charts, and photographers use them in darkrooms.\n\nFor gaming setups and content creation, a red screen provides dramatic background lighting for streaming and video production. It creates a bold, energetic atmosphere without the harshness of white light.\n\nRed light therapy enthusiasts also use full-screen red displays as a supplementary light source, though dedicated devices are more effective for therapeutic purposes.

Frequently Asked Questions – Red Screen

A red screen isolates the red sub-pixel in each pixel. If a sub-pixel is dead, it will appear dark against the red background. This catches defects invisible on white screens.

Red light has a longer wavelength and is less likely to suppress melatonin production compared to blue light. Using a red screen at night is less disruptive to your sleep cycle.

Yes. Red screens are used in darkroom photography to provide safe light that won't expose light-sensitive paper. Digital photographers use them as colored fill lights.

Try the Auto Color Cycle feature on this page. Rapidly cycling through colors can sometimes unstick a stuck pixel by stimulating the transistor. Run it for 20-30 minutes.