Flicker Test

Compare camera-visible bands or pulsing across controlled display brightness settings and browser patterns.

Go to test controls

This check runs directly on this page without requiring fullscreen. Review what this browser test can and cannot measure.

Before you start

  • Keep the same camera mode, position, room light, and static browser pattern; change only the display brightness setting between captures.
  • Use comfortable brightness and stop if viewing the screen causes discomfort.
Step-by-step instructions

How to run this check

  1. Keep room lighting steady and choose one phone camera mode
  2. Start the Flicker Test and keep one static browser pattern selected
  3. Use the phone camera to look for moving bands or pulsing
  4. Compare brightness A, B, then A again with the same camera exposure behavior, position, lighting, and static pattern
  5. Record camera settings and observed bands or not assessed; stop if uncomfortable and do not infer a dimming method from camera artifacts

Click to start the test. Have your smartphone camera ready. Press ESC to exit anytime.

Camera comparison: These backgrounds stay still. Keep the camera mode, position, room light, and browser pattern fixed while comparing display brightness settings. Stop if you feel discomfort.

What the camera showed

Record whether the same camera setup showed stationary bands, moving bands, pulsing, or no obvious pattern. Rolling shutter, exposure timing, stabilization, HDR capture, and other camera processing can create or change bands.

What changed with brightness

Compare display brightness settings while camera mode, frame rate, exposure behavior, distance, angle, and browser pattern stay fixed. A repeatable change is useful evidence about those conditions, not proof of a specific dimming method.

Record the original brightness as A, change only brightness for B, then restore A. Keep the same static background. If the camera changes its exposure automatically, record that limitation and leave the comparison uncertain.

What this cannot establish

Band count is not a PWM-frequency measurement. This page cannot calculate modulation depth, identify PWM or hybrid dimming, determine a hardware fault, or establish medical safety. Those questions require documented or instrumented testing.

What this browser test can tell you

Can help you check

  • Camera-assisted comparison across brightness settings.

Cannot measure

  • This test cannot measure PWM frequency, flicker percentage, or medical safety.

Interpret this observation

  • Record camera settings, display brightness, and actual patterns viewed. If exposure changed automatically or the method was not performed, leave the camera comparison unassessed; omitted comfort and brightness fields are not assumed.
  • Exact flicker frequency and modulation measurements require a photodiode and oscilloscope or a dedicated flicker meter.
Setup and sources

Recommended setup

  1. Use the same phone camera mode and position for each brightness setting.
  2. Compare brightness A, B, then A again with the same static pattern, fixed camera exposure behavior, and constant room light. Stop the comparison if uncomfortable.

Methodology reviewed: