How to use this tool
- Use your usual viewing distance and moderate room lighting.
- Switch between shadow detail and highlight detail.
- Look for visible boundaries between neighbouring patches.
- Change one monitor setting at a time and compare again.
GearCheck Lab // Free browser tool
Monitor Contrast & Black Level Test
Inspect steps near black and white to see whether dark or bright detail merges on your display. These are steady patterns with no flashing.
Monitor Contrast & Black Level Test workbench
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Read the result correctly
The numbers inside patches are RGB code values sent by the page. Near-black patches differ only slightly and may be difficult to distinguish in a bright room. Near-white patches can merge when display contrast or picture processing clips highlights. These observations help you compare settings but do not establish a universal pass/fail threshold. Keep browser zoom, colour mode and room light unchanged between runs. Fullscreen removes surrounding page content; Escape returns to normal browsing. The page does not change monitor settings.
Limits and troubleshooting
Browser colour management, HDR mode, panel technology and viewing angle affect the appearance. This cannot measure physical contrast ratio, luminance, gamma accuracy or HDR certification. Use calibrated equipment for those measurements. A screenshot captures code values rather than the physical appearance of your panel.
Privacy and control
Device previews, recordings, selected files and report notes stay in your browser. Downloaded files remain on your device. The call check sends small HTTP probes to GearCheck Lab. The WebRTC test exchanges temporary connection descriptions through our server and contacts the disclosed STUN service only after you create or join a session. Ordinary page requests and usage measurement are described in our privacy policy.