Decibic

Guided visual display checks

Monitor test

Inspect image fit, pixel mapping, tonal transitions, channel behavior, inversion patterns, and visible motion artifacts with deterministic patterns generated in this browser.

Observation aid only. It cannot calibrate color, measure response time or physical size, read the panel, or prove a defect.

How to use

  1. Prepare the real setup. Use your usual cable and picture mode, close overlays, keep room light steady, and set browser zoom to 100% if practical.
  2. Inspect one pattern at a time. Fullscreen is helpful for edge checks. Follow “Do,” “Look for,” and “Limit” before changing a display setting.
  3. Cross-check before deciding. Repeat suspicious results in normal content and, when possible, another browser or input. Change one setting at a time.

1 · Frame & clipping · viewport preview

1 Frame & clipping Edges and overscan · 1 of 9
Do

Enter fullscreen if available, then confirm every outer line, corner marker, and numbered inset remains visible.

Look for

Missing edges, unequal margins, or corner markers cut by overscan, zoom, an input scaler, or the visible viewport.

Limit

A complete frame only shows that this browser image fits; it does not identify which device or setting controls the mapping.

Ready. Pattern 1 is rendered locally; fullscreen is optional.

Focused shortcuts: ←/→ previous/next · 1–9 direct · Home/End first/last · F fullscreen · H controls · Space pattern action · Esc exits fullscreen.

Reading canvas size and browser pixel ratio…

Checking fullscreen and motion preferences…

What the patterns isolate

No score is calculated. Compare observations, settings, browsers, and familiar content.

1 · Frame & clippingEdge visibility, centering, overscan, and image fit.
2 · GeometryStraight grids, round circles, square cells, and aspect distortion.
3 · Fine detailOne- and two-bitmap-pixel rows, columns, checkers, and ringing clues.
4 · Gray rampContinuous 8-bit ramp beside deliberate 32-step references.
5 · Shadow detailNear-black code-value patches for visible crushing or tint.
6 · Highlight detailNear-white code-value patches for visible clipping or tint.
7 · Channel rampsNeutral, RGB, and CMY 8-bit ramps for channel-specific transitions.
8 · InversionStatic fine gray rows, columns, and checks with a manual phase swap.
9 · Motion transitionOptional moving light/dark blocks for subjective trails and overshoot.

Browser and signal path matter

Browser zoom, OS scaling, GPU range and bit depth, HDR, night modes, ICC color management, cables, input scalers, and monitor processing can all change the result. The reported pixel ratio is browser information, not proof of native panel mapping.

Visual checks are not calibration

The patterns cannot establish color accuracy, luminance, contrast ratio, gamma, response time, refresh rate, physical dimensions, or warranty status. Color-critical or timed measurements require suitable instruments and a controlled workflow.

Motion and visual comfort

Nothing moves automatically. The motion pattern starts only on request, stops on pattern changes, tab hiding, fullscreen exit, or Reset, and is disabled when reduced motion is preferred. Stop immediately if any fine pattern, shimmer, or motion causes discomfort.

Access, privacy, and screenshots

This tool requests only the Fullscreen API after your action. It requests no camera, microphone, screen capture, files, location, or device access, makes no network request, and stores nothing. A screenshot normally records the generated image—not physical panel artifacts, reflections, or viewing-angle effects.