Display Diagnostic Suite
Free online monitor and LED wall tests. Select a pattern below; open Advanced for cabinet layout and LED export controls.
Choose a display test
Click a pattern for an immediate display test, or select Advanced for precision patterns and LED wall controls.
Output settings · Resolution, grid & motion
Output controls
Tip: ← / → moves between patterns. Use your browser fullscreen exit key to leave fullscreen mode.
Color Bars 75%
Color and monitor signal testing.
Advanced display patterns
Select a precision, low-gray or motion test below. Results appear in the display preview above.
LED Wall Test Patterns & Cabinet Mapping
Set wall dimensions and pixel pitch to create a native-resolution test raster for LED cabinets. This separate LED output uses its own preview and download controls.
Cabinet specifications
Use real cabinet resolution from the manufacturer when nominal pitch is rounded.
Advanced Overlays & Logo +
LED wall preview
Live preview updates when you change any wall settings or pattern.
Numbers and grid overlays help with identifying cabinet position. Controller-port wiring requires separate processor mapping.
LED wall engineering guide, examples & FAQs — expand
LED wall test patterns: setup and commissioning guide
LED walls are built from cabinets and modules with discrete pixel dimensions. Pattern files should match the actual receiver-card and processor canvas to make pixel mapping issues visible before rehearsal. This generator estimates native pixels from nominal pitch and panel size, then builds a downloadable PNG. Always confirm the manufacturer’s real cabinet resolution: nominal pitch and nominal millimeter dimensions can produce a fractional value that should not be rounded silently for production.
Calculate the native wall resolution
Estimated pixels across a cabinet equal cabinet width in millimeters divided by pixel pitch in millimeters. Do the same for height. Multiply by cabinet columns and rows to estimate the whole wall canvas. For example, a 500 × 500 mm cabinet at 2.5 mm pitch yields 200 × 200 pixels. A wall four cabinets wide and three high yields 800 × 600 pixels and measures 2.0 × 1.5 meters physically. A 16:9 playback frame is not a pixel-perfect substitute for this 4:3 wall unless the content is intentionally fitted or cropped.
Which pattern should I use first?
Full red, green, blue and white fields help identify dead LEDs, wrong color channels and severe uniformity problems. A black field reveals unintended emission. The cabinet boundary grid and cabinet numbers make it easier to find a mispatched tile, incorrect rotation, or seam alignment. Checkerboard and crosshatch patterns are useful for spot-checking receiver-card mapping; fine pixel-level patterns can show unwanted scaling and sampling issues.
Alignment and controller port work
The numbered overlay identifies cabinet positions in left-to-right, top-to-bottom order for reference; it is not a wiring map and does not determine controller-port order. Check actual signal daisy-chain order with the LED processor's configuration tool. If a cabinet is rotated or its module scan type differs, the screen can display an apparently valid image but still have missing rows, swapped quadrants or unexpected grayscale behavior.
Color bars, grayscale and low light
Gradient and 11-step grayscale patterns help identify visible banding, poor gamma handling and nonuniform brightness. Low-gray steps can expose calibration differences between cabinets. Perceptual judgments depend on wall brightness, room light, viewing distance, camera shutter, and active processor calibration. Computer RGB PNGs do not replace a calibrated colorimeter or a manufacturer-supplied commissioning sequence.
Export and signal-chain checks
Use the PNG export to create a file at the calculated wall's exact pixel width and height. Upload it to the content server and inspect whether playback, scaling, LED processor and mapping maintain a one-to-one pixel relationship. The optional logo overlay is useful for demonstration, not for testing absolute channel levels. Do not assume that browser fullscreen will send the wall its native raster; the export file is preferable for testing through the actual show signal chain.
Common questions
Why is the estimated cabinet resolution not an integer?
Nominal panel dimensions and pixel pitch sometimes do not divide evenly. Consult manufacturer cabinet/module documentation to avoid rounding errors.
Can I make a wall with non-rectangular or mixed cabinets?
This tool generates a rectangular grid of uniform cabinets. Mixed resolutions and irregular edges require a zone map made for the specific processor.
Does the grid represent controller output ports?
No. It marks cabinet boundaries only; real output-port mapping must be completed in processor software and confirmed on the wall.
What is the best way to test full-resolution content?
Export a PNG matching confirmed native wall pixels, play it through the show media server, and validate it on the installed LED system with processing and scaling settings recorded.
Engineering guide, examples & FAQs — expand
Display testing and monitor calibration: a field guide
Use the Display Diagnostic Suite to inspect LCD, OLED, video-monitor, confidence-monitor, and playback-display behavior. A browser-based pattern can reveal obvious pixel faults, geometric scaling, low-gray artifacts, and response issues, but it cannot replace calibrated instruments for measuring color accuracy, transfer functions, or peak luminance. Patterns are generated by the browser, so operating-system color processing, output range, scaling, HDR settings, and the display itself all influence what reaches the panel.
Step 1 — Inspect dead, stuck, and weak pixels
Start with the black, white, red, green, and blue fills in a darkened room. A stuck-on pixel may appear as a colored point on a black field. An unresponsive subpixel can appear as a dark point on a single-color field. At large screens, inspect several areas at close range; a photograph taken from across a venue may hide isolated faults. Try different source devices before concluding that a faint artifact originates inside the panel.
Step 2 — Check uniformity and low-gray behavior
Display 5%, 10%, and 50% gray fields. Near-black tests can expose vertical streaks or uneven OLED response that full-white patterns conceal. The 50% pattern is useful for noticing clouding and dirty-screen effects. Run comparisons after a normal warm-up period and at a typical brightness setting; unusually high or low brightness changes perceived severity. Pixel or color differences that appear only in screenshots may come from the capture pipeline rather than the monitor.
Step 3 — Evaluate bars, grayscale, and black setup
Use reduced-level and full-level RGB bars to spot gross signal-routing or processing errors, not as a substitute for a standards-compliant test signal from a verified video generator. The grayscale and near-black patterns help reveal banding, clipping, or restricted-range mismatches. PLUGE-style patterns provide a visual aid for setting perceived black level; accurate television calibration requires a known electrical/legal signal range, a defined transfer function, a controlled environment, and a measuring device.
Step 4 — Look for scaling and motion faults
Display the 1-pixel sharpness pattern at the display's native output resolution where practical. Fine details that blur, shimmer, or vanish can indicate scaling, overscan, chroma subsampling, or processing. Geometry circles and alignment grids can reveal a stretched picture. The moving object highlights visible smearing or inverse ghosting; animation is affected by the browser refresh cycle, operating-system compositor, and captured frame rate.
Fullscreen, output settings, and PNG downloads
Fullscreen uses the available browser viewport; the browser may still apply scaling and color management. For an exact raster file, choose the output pixel dimensions and export a PNG. A PNG itself does not encode test-signal electrical levels or guarantee broadcast-standard accuracy. For mission-critical calibration, compare its appearance with a certified external pattern generator and known reference monitor.
Common questions
Can a browser show one physical pixel per test pixel?
Sometimes, if browser zoom, device-pixel ratio, output scaling and panel mapping align. Verify the complete display chain before trusting a one-pixel pattern.
Does a 75% color-bar image certify SMPTE compliance?
No. These are SMPTE-inspired digital RGB reference patterns. Electrical SDI waveform, legal-range encoding, HDR transfer function and measured output are not guaranteed by a browser image.
Why do my OLED near-black steps blend together?
They may reflect panel behavior, brightness settings, ambient light, browser processing, clipping or output range. Compare multiple known sources before adjusting calibration.
Why does the fullscreen output differ from a downloaded PNG?
Fullscreen follows browser viewport and device-pixel-ratio rendering. The downloaded PNG uses the exact width and height selected in the tool.
About this free online display testing tool
This browser-based display diagnostic tool generates patterns on demand without installing software or uploading an image. Use solid red, green, blue, black and white fills to look for individual panel defects. Grayscale ramps and color bars help reveal crushed shadows, clipping, banding or channel problems in the signal chain. The optional LED wall controls calculate raster size from cabinet counts and pixel pitch, making it easier to export a properly sized pattern for a media server or LED processor.
The pattern visible on a display can be affected by browser scaling, operating-system color management, display settings and the processing equipment. For a reliable commissioning check, confirm the output resolution and scaling at each stage and, where needed, verify performance with calibrated measurement instruments. The display tests are free and run directly on your device; no account is required.