Display diagnostics

LCD Test Online

Use fullscreen patterns to check dead pixels, backlight bleed, gradients, sharpness, and motion ghosting.

Ready to test

Screen Test Workbench

Pick a pattern. Preview it. Then check the full screen.

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Screen
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Live preview Black Use solid colors. Look for a pixel that stays dark, bright, or one color.

A complete check in about one minute

Twelve timed steps cover primary colors, dark tones, gradients, and motion.

  1. 1Solid colors
  2. 2Dark tones
  3. 3Grayscale
  4. 4Motion
12 steps 4s per step Pause anytime

In fullscreen, use arrow keys to move. Space pauses Guided Test or advances Manual Test. Esc exits.

Choose by goal

Pick the right screen test

Start with Quick for a broad check. Use a focused mode when one issue needs a closer look.

Before you start

Six quick steps for a cleaner result

  1. 01

    Clean the screen

    Wipe away dust and fingerprints before you judge a small mark.

  2. 02

    Use native resolution

    Set the display to its recommended resolution before you inspect fine lines or text.

  3. 03

    Let brightness settle

    Wait a moment after changing brightness so the picture stays steady during the test.

  4. 04

    Pause auto brightness

    Turn off automatic brightness so dark and light patterns do not change the display while you inspect them.

  5. 05

    Pause picture enhancements

    For SDR patterns, pause dynamic contrast and similar picture changes. Restore your settings when you finish.

  6. 06

    Dim the room only when needed

    Lower room light for a backlight check. Judge any glow from your normal seat because viewing angle can change it.

Reading results

What to look for

Dead and stuck pixels

Check the mark on red, green, blue, white, and black. A pixel defect stays fixed. Dust or a reflection may shift, soften, or vanish after cleaning.

Backlight bleed and uniformity

Use black or 5% gray in a dim room. Check from your normal seat. Edge bleed stays near the frame. Panel glow often changes with your viewing angle.

Gradient banding

A smooth fade should not break into hard steps. If bands appear in only one photo or video, the source may contain them.

Motion ghosting

Follow the moving edge. Trails show ghosting. Bright inverse halos can point to strong overdrive. Some blur is normal while an object moves.

Sharpness and scaling

Fine lines and text should stay distinct. If they blur or shimmer, first use native resolution and review display scaling and browser zoom.

FAQ

Screen test questions

How do I tell dust from a dead pixel?

Clean the screen, then check the mark on several colors. Dust may move or fade. A pixel defect stays in the same spot.

Does this test measure color accuracy?

This test can show visible tint, bands, and uneven color. For exact color results, use a color meter.

Why test in fullscreen?

Fullscreen hides most browser controls and fills the edges. Small pixel and backlight issues are easier to see.

What should I do after finding a defect?

Run the test again and note the spot. Then read the support or pixel policy for your model and region.

Do I need a dark room?

No. Use normal room light for pixel and sharpness checks. Dim the room only for dark-screen uniformity and backlight checks.

Can I use this test on a phone or tablet?

Yes. The patterns work on mobile screens. Some browsers keep a small system bar visible, so inspect that edge again after rotating the device.

Can a screenshot record a physical dead pixel?

A screenshot records the image sent to the display, not the panel itself. Follow the maker's support steps if it asks for a photo or other proof.

How long does a screen test take?

The Guided Test takes about one minute. A focused check usually takes a few more minutes when you repeat a suspicious pattern.

Next step

Check the screen again

Run the guided sequence for a broad pass, or return to the workbench and focus on one pattern.