Eye response frequency depends on the light intensity. We can track higher frequencies when the lights are brighter. Dim theatres played a role in preserving th

Eye response frequency depends on the light intensity. We can track higher frequencies when the lights are brighter. Dim theatres played a role in preserving the illusion of motion when movie frame rates were very low. You can also perceive very high frequency lights by the strobe effect. For example if you wave your hands in front of a PWM LED or a bad fluorescent light you can quickly tell. By moving my eyes quickly from left to right, I can easily spot the order in which my office projector flashes the colour components of its image.