Bright-pixel inspection
Look for white or colored points that remain visible on black.
Black Screen
Use a full-screen black background to reveal bright pixels, backlight bleed, edge glow and image retention in a dark room.
What is a black screen used for?
A black screen helps reveal pixels that remain bright, light leaking around panel edges, cloudy backlight areas and possible image retention. Room lighting, brightness level and panel technology can change what you see.
✓ No installation✓ Full-screen support✓ Works on compatible devices
Useful checks with a black screen
Backlight bleed
Inspect corners and edges for fixed light patches in a dark room.
OLED black check
Observe whether black areas appear fully dark on compatible OLED panels.
Image retention
Check whether a previous image remains faintly visible after content changes.
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
Is IPS glow the same as backlight bleed?
No. IPS glow often changes with viewing angle, while backlight bleed is usually more fixed near edges or corners.
Should the room be completely dark?
A dim room makes light leakage easier to see, but test at the brightness level you normally use as well.
Can this page measure black level accurately?
No. It supports visual inspection only; calibrated measurement requires a colorimeter or other display hardware.
Try another screen color
Run several colors because different pixel and uniformity problems appear on different backgrounds.
Explore more diagnostics
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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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