Koler — Visual Display Tests

Screen & Monitor Pattern Tools

Only for Mac

Free

Mac

20+ full-screen visual tests for your Mac display. Check pixels, backlight, colors, gradients, contrast, burn-in, and more — fast, native, no permissions required. Koler is a collection of 20+ full-screen visual tests for your Mac display. Check pixels, backlight, colors, gradients, contrast, burn-in, and more — all in one fast, native app. Pick a test, go full-screen, and see for yourself. — WHAT YOU CAN VISUALLY CHECK — • Pixels — solid color screens make non-working dots easy to spot • Backlight bleed — dark screens reveal light leaks along the edges • Screen burn-in — gray shades and checkerboards expose OLED ghosting • Screen uniformity — solid fills show brightness and color inconsistencies • Color accuracy — reference photos and gamut comparison (sRGB vs Display P3) • Gradients — smooth transitions expose banding artifacts • Contrast — near-black and near-white levels test shadow and highlight detail • Motion clarity — a moving UFO object reveals ghosting and response time issues • Gamma — stripe patterns verify correct gamma curve • Text rendering — font samples at multiple sizes check subpixel smoothing • PWM flicker — stripe patterns you can photograph to detect flicker • And more — 20+ visual tests covering every aspect of display quality — VISUAL TESTS — Visual Pixel Check: • Solid Colors — full-screen white, black, red, green, blue, and gray Visual Motion & Response: • Response Time UFO — moving object test for ghosting and motion blur Visual Assessment: • Photo Assessment — reference landscape photos for color and tone evaluation • Sunset Gradient — timelapse gradient scenes for color accuracy • Liquid Glass — macOS 26 glass material rendering reference Visual Color & Calibration: • Gradient — smooth horizontal and vertical gradients to reveal banding • Color Gamut — sRGB vs Display P3 side-by-side comparison • Gamma — 1px stripe patterns vs solid blocks for gamma verification Visual Screen Quality: • Contrast — near-black (1–5%) and near-white (95–99%) blocks • Backlight Bleed — black and near-black screens for dark room inspection • Screen Burn-in — gray shades and checkerboard for OLED screens • Screen Uniformity — solid colors to check brightness and color consistency • Frontend Contrast — subtle brightness grid for fine contrast evaluation • PWM Flicker — stripe patterns to photograph with your phone camera Visual Sharpness & Rendering: • Sharpness & Geometry — grids, circles, checkerboard, and text samples • Text Rendering — font smoothing and subpixel rendering at multiple sizes • Viewing Angles — color and brightness shift from different angles • Crosshair — centered crosshair with ruler markings and optional grid Plus detailed Display Information for each connected screen: resolution, refresh rate, color space, HDR status, and more. — WHY KOLER — • 20+ full-screen visual tests in one app • Visual assessment with reference photos and video • Liquid Glass rendering reference (macOS 26) • Auto-cycle mode — press A to auto-advance through colors every 3 seconds • Display info panel with HDR, ProMotion, and EDR details • 100% native macOS app — instant launch, zero lag, tiny footprint • Works with built-in displays, external monitors, and projectors • Multi-monitor support — pick which display to test • Full-screen patterns with keyboard, mouse, and trackpad navigation • Clean, intuitive interface — no ads, no clutter • No permissions required — the app doesn't access your camera, microphone, or files Perfect for designers, photographers, video editors, colorists, gamers, IT professionals, and anyone buying or setting up a new monitor. Koler displays visual reference patterns for your own assessment. It does not perform automated hardware diagnostics. If you experience display issues, contact Apple Support or your monitor manufacturer.

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• Added new visual tests • Bug fixes and performance improvements

Version 1.2

The developer, Pavel Devyatov, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .

  • Data Not Collected

    The developer does not collect any data from this app.

    Privacy practices may vary, for example, based on the features you use or your age. Learn More

    Accessibility

    The developer has not yet indicated which accessibility features this app supports. Learn More

    Information

    Seller
    • Pavel Devyatov
    Size
    • 54.4 MB
    Category
    • Graphics & Design
    Compatibility
    Requires macOS 15.0 or later.
    • Mac
      Requires macOS 15.0 or later.
    Languages
    English and 9 more
    • English, French, German, Italian, Japanese, Korean, Portuguese, Russian, Simplified Chinese, Spanish
    Age Rating
    4+
    Copyright
    • © 2026 Pavel Devyatov
  • Privacy Policy