Blue-subpixel check
Find points that appear dark, red, green or white against blue.
Blue Screen
Use a pure blue full-screen field to inspect blue subpixels, color uniformity and points that remain red, green, black or white.
What is a blue screen used for?
A blue screen isolates the blue component of the panel for visual inspection. It can expose pixels that fail to show blue or stay on another color, but it cannot provide laboratory color measurements.
✓ No installation✓ Full-screen support✓ Works on compatible devices
Useful checks with a blue screen
Tint inspection
Compare blue tone across different parts of the screen.
Pixel confirmation
Check the same location on red, green, white and black pages.
Ambient blue background
Use a blue field for simple lighting or camera-background experiments.
How to use this screen safely
- Clean the display gently according to the manufacturer’s instructions.
- Use your normal viewing distance and brightness first.
- Open full screen and inspect the center, edges and corners.
- Repeat the check with black, white, red, green, blue and gray backgrounds.
- Do not stare at an uncomfortable brightness or color for a prolonged period.
Important: This is a visual browser test. It cannot certify a display, identify the exact hardware cause, or replace professional measurement equipment.
Frequently asked questions
Why can blue look darker than green?
Human vision and display subpixel output make equal digital values appear different in brightness.
Can this page diagnose a graphics-card problem?
It may reveal visible artifacts, but it cannot determine whether the cause is the panel, cable, graphics hardware, driver or software.
Should HDR be enabled?
Test both your normal configuration and standard dynamic range if you are troubleshooting color behavior.
Try another screen color
Run several colors because different pixel and uniformity problems appear on different backgrounds.
Explore more diagnostics
View all testsChoose another test
Move between screen, camera, audio and device checks without returning to the homepage.
Dead Pixel TestInspect solid colors for dead, stuck, bright or dark pixels.
Touch Screen TestCheck touch coverage, dragging continuity and dead zones.
Keyboard TesterTest a full-size keyboard and confirm every key press.
Mouse TesterTest buttons, wheel, movement, dragging and double-clicks.
Audio TesterCheck speakers, stereo channels, tones and microphone input.
Camera & WebcamTest built-in, USB, phone, tablet and compatible TV cameras.
Microphone TesterView microphone levels, waveform, recording and playback.
Pixel ExerciserExercise a suspected stuck-pixel area with changing colors.
Gradient TestInspect gradients, tonal transitions and visible banding.
Brightness & ContrastCheck black levels, white saturation and contrast separation.
Screen Size TestView viewport, resolution, pixel ratio and display data.
Text SharpnessInspect text rendering, browser scaling and clarity.
Motion & GhostingObserve motion blur, ghosting and response behavior.
Resolution & ScalingCheck screen resolution, CSS pixels and scaling.
Device InformationReview screen, browser, hardware and platform information.
Browser CapabilityCheck which browser APIs and hardware features are supported.
Network TestCheck connection status, latency and estimated download speed.
GPS & LocationTest browser geolocation, accuracy, altitude and speed.
Sensor TesterTest orientation, motion, acceleration and rotation sensors.
Multi-Touch TesterTrack multiple touch points, pinching and rotation gestures.Screen Color ToolsOpen exact full-screen color pages for pixel, uniformity and lighting checks.Response Time TestObserve ghosting, blur and pixel-transition behavior at several speeds.Stylus Drawing TestCheck pen, touch, pressure, tilt and drawing continuity in your browser.
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