⚠

Photosensitivity Warning

This tool produces rapidly flickering light across the full screen at frequencies between 1 and 40 Hz.

By proceeding you acknowledge these risks and confirm this tool is safe for you to use.

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Ganzflicker

Uniform-field photic stimulation
Close eyes after starting · Tap to begin
Inactive —
00:00
Space Start/Stop   F Fullscreen   Esc Exit

Frequency Target

Flicker rate mapped to brainwave bands
Fine tune 10.0 Hz

Flicker Waveform

Temporal envelope of light modulation
Square Hard on/off
Sine Smooth pulse
Sawtooth Gradual rise
Duty cycle 50%
Brightness 80%
⚠ Flickering light warning. This tool produces rapid full-field flashing. Not recommended for individuals with photosensitive epilepsy. Close your eyes during the session — the light passes through the eyelids to produce the Ganzfeld effect. Stop immediately if you feel any discomfort.

Color Field

Stimulus and background color

Session Timer

Auto-stop after duration (0 = unlimited)
Duration 10 min

About the Ganzflicker

The Ganzfeld effect occurs when the visual system is exposed to a uniform, undifferentiated field of light. Under these conditions, neurons in the visual cortex — deprived of their usual edge-detecting inputs — begin to amplify internal noise, often producing geometric patterns, color shifts, and altered perceptual states.

When combined with rhythmic flickering (photic driving), the brain's oscillatory activity can entrain to the stimulus frequency. Flicker in the alpha range (8–13 Hz) has been reported to produce vivid closed-eye imagery. This effect has been studied since antiquity — Ptolemy noted visual patterns from spinning spoked wheels in sunlight.

For the intended effect: enter fullscreen, select your frequency, begin the session, then close your eyes and observe what arises in the visual field behind your eyelids.