Flicker fusion frequency

Flicker fusion frequency, also known as the critical flicker fusion frequency (CFF), refers to the minimum frequency at which a flickering light source appears steady or continuous to an observer. It is the point at which the flickering light transitions from being perceived as individual flashes to a continuous and smooth illumination.

The human visual system has a limited ability to perceive rapid changes in light intensity. When the frequency of a flickering light source exceeds the individual's CFF, the light appears as a steady glow rather than discrete flashes. The CFF varies among individuals but is generally around 60 to 90 Hz for most people.

Flicker fusion frequency has practical implications in various fields, including lighting design, display technologies, and entertainment. For example, it is important in designing lighting systems that avoid noticeable flicker and in determining refresh rates for electronic displays such as televisions and computer monitors to provide smooth motion without visible flickering.

It's worth noting that individual sensitivity to flicker can vary due to factors such as age, health conditions, and ambient lighting conditions. Additionally, technological advancements have allowed for higher refresh rates on displays, reducing or eliminating visible flicker for most people.