Screen Test
Test your display with solid colors and gradients. Click a color to go fullscreen.
Press ESC or click to exit
What to Look For
- Dead or stuck pixels (bright dots on black, dark dots on white)
- Uneven backlight (light bleed on edges with black screen)
- Color accuracy (reds should look red, not orange)
- Banding in gradients (visible steps instead of smooth transitions)
How to Use This Test
- Click any color button in the grid above to display that color in fullscreen mode on your monitor.
- Examine the entire screen carefully for dead pixels, stuck pixels, or uneven areas while in fullscreen.
- Use the Auto Cycle, Gradient, and Checkerboard modes for a thorough display assessment, then press ESC to exit.
What This Test Checks
This screen test displays solid colors, gradients, and patterns in fullscreen to help you identify display defects and evaluate overall screen quality.
- Dead pixels (always dark) and stuck pixels (always bright or one color)
- Backlight uniformity and light bleed around edges
- Color accuracy and saturation for primary and secondary colors
- Gradient smoothness and color banding issues
- Overall display panel quality and consistency
Troubleshooting
If you're having issues:
- Make sure your display brightness is set to a comfortable level and your room lighting is dim for best visibility.
- If fullscreen mode does not activate, try pressing F11 or check that your browser allows fullscreen display.
- For accurate color testing, disable any night mode, blue light filter, or color profiles temporarily.
- If you find dead pixels on a new monitor, contact the manufacturer as most have dead pixel warranty policies.
Understanding What You're Seeing
Dead pixels vs stuck pixels vs dust
A dead pixel is permanently off and shows as a black dot on every color. A stuck pixel is locked to one of red, green, or blue and stays that color on any background. Dust on the screen looks similar but can be wiped away. For a dedicated check on any color, use the dead pixel test.
Backlight bleed vs IPS glow
- Backlight bleed: bright patches on the edges or corners during a black screen, visible from any angle. Often grounds for RMA if severe.
- IPS glow: a soft off-angle glow that shifts as you move your head, most visible in dark rooms. It's inherent to IPS panels — not a defect.
- To tell them apart, view the black test from directly in front at arm's length. Bleed stays; glow vanishes.
Color banding in gradients
Banding is visible stepping in the gradient test rather than a smooth transition. Causes:
- 6-bit panel with FRC (cheaper monitors/laptops) — the panel dithers to simulate 8-bit colors but banding shows on slow gradients.
- Video cable bottleneck: older HDMI 1.4 or a bad DisplayPort cable may force 6-bit output. Swap for a certified HDMI 2.0+ or DP 1.4 cable.
- GPU output setting: in NVIDIA Control Panel → Change resolution → Output color depth, set to 8-bit (or 10-bit if your panel supports it).
Uniformity issues
On a full-white test, check for pink tint, yellow edges, or dark patches in the middle. Panel uniformity deviations of ±10% brightness across the screen are within spec for most consumer monitors. Professional panels (ASUS ProArt, EIZO ColorEdge) offer factory-calibrated uniformity compensation.
Fix Color and Display Issues by OS
Windows 10 / Windows 11
- Open Settings → System → Display. Toggle off Night light, HDR, and Auto color management when running this test for the cleanest output.
- Calibrate via Settings → System → Display → Color profile → Calibrate display (or the classic
dccw.exetool). - If colors look washed out after a driver update, go to NVIDIA or AMD control panel and set Dynamic Range to Full (0-255) — TV-mode Limited (16-235) compresses everything.
macOS
- Open System Settings → Displays → Color profile. Pick the factory profile or run Customize → Calibrate (hold Option when clicking Customize for the advanced wizard).
- Disable Night Shift and True Tone (Displays → Night Shift) when checking colors — both shift white balance.
- External monitors may inherit a generic profile; click Display settings → Color profile → Show profiles for this display only to pick a manufacturer-supplied ICC.
Linux
- GNOME: Settings → Displays → Color calibration (requires
gnome-color-manager). - KDE: System Settings → Color Management.
- For precise calibration with a colorimeter, use
DisplayCAL— works with X-Rite / Datacolor hardware.
Next Steps for Monitor Diagnosis
If this test reveals issues, dig deeper with the related tools: the dead pixel test for stuck-pixel repair cycling, the brightness test for backlight uniformity, the refresh rate test to verify your monitor runs at its rated Hz, and the GPU test if you suspect the graphics card is outputting the wrong bit depth or color range.
Frequently Asked Questions
How do I check for dead pixels on my monitor?
Click on a solid color (especially white, black, red, green, and blue) to view it fullscreen. Carefully scan the entire screen for tiny dots that do not match the displayed color. Dead pixels appear as black dots on colored backgrounds, while stuck pixels show as bright colored dots on a black background.
What is backlight bleed and how do I detect it?
Backlight bleed is when light leaks around the edges or corners of an LCD screen, most visible on a black background. Use the black color test in a dark room and look for lighter areas along the edges. Some bleed is normal on IPS panels, but excessive bleed may indicate a defective display.
Can I use this test to calibrate my monitor colors?
This test helps you visually assess color accuracy by displaying pure colors and gradients, but it is not a substitute for professional monitor calibration. For precise calibration, use a hardware colorimeter along with calibration software. This test is useful for a quick visual check.
Why do the colors look different on my screen compared to another monitor?
Color differences between monitors are caused by varying panel types (IPS, VA, TN), color gamut coverage, factory calibration, brightness settings, and color temperature. Each display renders colors slightly differently unless both are professionally calibrated to the same standard.
Time to upgrade? Consider these monitors:
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