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09CONTRAST / SHADOW + HIGHLIGHT

Contrast & Shadow Detail Test

Compare tightly spaced values near black and near white to see whether your settings hide shadow detail or clip highlights, then use a checkerboard to judge how dark black stays next to bright white.

  • 3 patterns
  • Fullscreen
  • No install

Browser-generated pattern · Not a laboratory measurement

PATTERNS / 03

Patterns in this test

Each pattern targets a different symptom. Start from the top, or jump straight to the one you need.

  1. 01

    Near-black levels · 0–30

    Count the boxes you can separate from the background. In a dim room, levels from about 4–6 should show; if 10+ vanish, shadows are crushed.

  2. 02

    Near-white levels · 225–255

    Each box should differ from pure white (255). If 245–254 merge into the background, highlights are clipping: lower contrast.

  3. 03

    Checkerboard contrast

    Black squares should look as dark as on a full black screen. Gray or uneven blacks reveal glare, blooming or low native contrast.

PROTOCOL / 01—04

How to use this test

Keyboard and touch

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Show controls on touch screens and mice
  1. 01

    Clean the screen gently and let it reach its normal operating temperature.

  2. 02

    Set browser zoom to 100% and use the brightness and picture mode you normally use.

  3. 03

    Start fullscreen mode. Each pattern shows a short hint about what to look at.

  4. 04

    Observe from your normal position first, then move closer only to inspect a detail.

OBSERVE

What to look for

  • Boxes separated from the black background
  • Bright boxes separated from the white background
  • Black checkerboard squares as dark as a full black screen

INTERPRET

How to read the result

If the darkest boxes merge, check black level, RGB range (full vs limited) and gamma. If the brightest merge, reduce contrast or inspect HDR and video-range settings. Grayish checkerboard blacks indicate glare, blooming or limited native contrast.

LIMITS

Limits of a browser test

Correct visibility depends on room light, display technology, gamma target and intended video range. More visible boxes are not always more accurate.

FAQ

Frequently asked questions

01What is black crush?

Black crush occurs when several dark tones are rendered as the same black, hiding shadow detail.

02Should reference black be invisible?

Yes: the 0 reference is the background. Levels just above it should become gradually visible under suitable conditions.

03Why does a limited RGB range crush shadows?

Limited range maps black to level 16 instead of 0. If the PC sends full range and the display expects limited, everything from 0 to 16 merges into black; the opposite mismatch makes blacks look gray.

NEXT / SCREENPROBE

Continue checking

03

Grayscale & gamma

Neutral steps, a gamma chart and RGB channel tracking.

↗ 04

Color banding

Reveal posterisation in smooth light and dark gradients.

↗ 05

Colour & gamut

Colour bars, full spectrum, saturation and a wide-gamut check.

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