Dead Pixel Tester
Display diagnostic

Backlight Bleed Test Online for Monitors, Laptops and TVs

Use a pure black field to inspect corner glow, clouding and IPS glow. Use this free fullscreen display test on an LCD, OLED, laptop, phone or TV. It runs locally in your browser with no download or account.

How to use this Backlight Bleed Test and understand the result

Set a dark test field at the brightness you normally use and view the panel straight on. Test in a dark room at your normal viewing angle before judging severity.

What this online Backlight Bleed Test can reveal

Glow confined to corners can be normal IPS behavior; a fixed bright patch that distracts during dark scenes is more significant.

Limits of this browser test

A phone camera can exaggerate bleed, so confirm from your seat before comparing panels. Repeat any suspicious result on another input or browser before requesting a return, warranty inspection or calibration.

Display diagnostics

Focused checks for panel uniformity, motion, color and HDR-era display behavior.

Backlight BleedUse a pure black field to inspect corner glow, clouding and IPS glow.GreyscaleScan a smooth set of neutral tones for crushed shadows, clipping and banding.Color AccuracyCompare a balanced reference palette across skin, foliage, sky and neutral swatches.Color GamutInspect saturated ramps and hidden-pattern fields to understand color coverage.Refresh RateMeasure the animation cadence your browser can sustain and watch for uneven pacing.GhostingFollow moving high-contrast blocks to spot trailing, smearing and inverse ghosting.BloomingBright shapes on black reveal halo spread from local-dimming zones.Burn-inCycle uniform colors and patterns to inspect OLED retention or uneven wear.Color BandingReveal stepped transitions in gradients that should appear smooth.ContrastCheck black-white separation and fine transitions at multiple line widths.HDRCompare highlight detail, deep blacks and vivid color in an HDR-ready pattern.Touch ScreenTrace a responsive grid to find dead zones, missed touches and inconsistent tracking.Screen TearingMove synchronized bars across the display to reveal tearing and frame pacing issues.Black LevelInspect near-black steps to check shadow detail, crush and panel uniformity.RGB ChannelCycle isolated red, green and blue fields to spot channel tint and stuck subpixels.sRGB ColorUse a compact sRGB reference palette to check clipping, tint and oversaturation.P3 GamutExplore vivid Display-P3 swatches and gradients on wide-gamut displays.BrightnessCompare luminance steps from near-black to white and check for clipping or unevenness.Gamma CalibrationTune mid-tone visibility with a neutral gamma reference pattern.FlickerShow controlled light and dark modulation to help reveal PWM or temporal dithering.Color DepthCompare stepped and dithered gradients to identify limited color depth or banding.Monitor ColorReview a complete color-card sequence for tint, clipping, uniformity and calibration drift.