Flicker Test

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

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

Before you start

Use one phone camera mode and keep its position fixed between comparisons.
Stop immediately if the flashing patterns cause discomfort.

How to run this check

Keep room lighting steady and choose one phone camera mode
Start the Flicker Test
Use the phone camera to look for moving bands or pulsing
Repeat with the same camera position at several brightness settings
Record the brightness and camera settings; camera artifacts alone do not identify the display dimming method

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.

Setup, interpretation, and sources

Recommended setup

Use the same phone camera mode and position for each brightness setting.
Compare several display brightness levels while other lighting stays constant.

How to interpret what you see

Record the brightness and camera settings where moving bands or pulsing appear.
Exact flicker frequency and modulation measurements require a photodiode and oscilloscope or a dedicated flicker meter.

Methodology reviewed: 2026-07-26

💡 Why This Test?

Some displays vary light output over time, and phone cameras may show moving bands or pulsing that are difficult to see directly. Camera shutter behavior can also create artifacts.

Use the same phone camera mode and position to compare several display brightness settings. This page cannot identify a dimming method, measure PWM frequency or flicker percentage, or determine medical safety.

✅ What You'll Check:

Camera-visible bands or pulsing across brightness settings
Whether the appearance changes when camera settings stay fixed
Your own comfort observation during the short comparison
The display brightness used for each observation
The camera mode, frame rate, shutter behavior, and position

📖 How to Use This Test

Set your monitor brightness to your normal usage level (40-60%)
Have a smartphone camera ready (any phone will work)
Start the test and navigate through 7 flicker patterns
Point your phone's camera at the screen during each pattern
Look for horizontal bands or pulsing and record the camera settings used
Note your eye comfort level during the test
Test again at different brightness levels for comparison

⚠️ Warning: This test contains rapid flashing patterns. If you have photosensitive epilepsy or feel discomfort, exit immediately. The camera method is safer than watching directly.

Tip: Repeat at several brightness settings without changing the phone mode or position. Bands can come from the interaction between camera shutter timing and the screen, so they are not a frequency reading or diagnosis.

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

Pattern

1 / 7

Use your camera to compare the screen at fixed settings. Record any horizontal bands or pulsing without assigning a dimming method.

Keyboard: Left/Right changes pattern, Space advances, and Escape exits.

🔧 Common Issues & Solutions

📱 "Camera shows horizontal lines but eyes don't see flicker" (PWM frequency)

What you observed: The camera showed horizontal bands while you did not notice direct flicker.

Interpretation: Band spacing depends on camera frame rate, shutter timing, rolling shutter, exposure, the displayed pattern, and screen behavior. More bands do not provide a reliable PWM frequency.

Next step: Record the camera settings and brightness, then repeat without changing the setup. Use a photodiode and oscilloscope or a dedicated flicker meter for frequency and modulation measurements.

💡 "Flicker-free at 100% brightness but flickers at 30-50%" (Hybrid dimming)

What you observed: Camera-visible bands appeared at one brightness setting but not another.

Interpretation: The change is useful comparison data but does not identify whether the display uses PWM, DC, hybrid dimming, temporal dithering, or another process.

Next step: Compare several brightness settings with the same camera setup and consult instrumented measurements or manufacturer documentation for the exact model.

📸 "Camera test shows banding - is this harmful?" (PWM sensitivity varies)

What you observed: The camera showed bands. That does not by itself establish a health effect or your personal sensitivity.

Safety: Stop rapid flashing immediately if you feel unwell. This short browser comparison is not a medical test and cannot connect a symptom to one display mechanism.

Next step: Do not extend exposure as a self-diagnosis. Use comfortable settings, take breaks, and seek qualified medical advice for persistent or severe symptoms.

😣 "Eye strain even on flicker-free monitor" (Other causes beyond PWM)

What you observed: Discomfort occurred even though the current camera setup showed no obvious bands.

Interpretation: Glare, dryness, posture, viewing distance, brightness, task duration, motion, and many other factors can affect comfort. This page cannot isolate a cause.

Next step: Adjust one reversible setting at a time, reduce glare, take breaks that feel useful, and seek qualified medical advice for persistent or concerning symptoms.

🎮 "Screen brightness appears to pulse during gaming"

What you observed: Brightness appeared to change while game motion or frame delivery changed.

Interpretation: The observation may change with game content, frame pacing, display settings, adaptive-sync settings, brightness, capture method, and display behavior. This browser page cannot identify the hardware cause or measure the fluctuation.

Next step: Reproduce the observation with the same scene, then compare one reversible game or display setting at a time. Consult the display and graphics documentation for supported settings.