Imaginary colors

Explore colors your eyes seem to create, even though the screen shows only two colors.

  1. Keep your gaze on the white dot at the center.
  2. Wait through the initial delay. Avoid following the circle's edge with your eyes.
  3. As the circle shrinks or expands, notice any unexpected colors where the two areas meet.
  4. Restart and try other color pairs or timing settings to compare the effect.

Why does this happen?

Prolonged viewing changes your visual system's sensitivity to a color. When the moving edge reveals a different color, a temporary afterimage can alter what you perceive there. You might see cyan or other fleeting hues that aren't actually drawn on the screen.

Results vary by person, display and viewing conditions. Hold your finger on the scene to pause; release to resume.

Configure

Initial delay
Mode
Animation duration
Colors
Keep looking at the white dot. Hold the scene to pause; release to resume. Tap ? for the explanation.