Which CFF law states that the high frequency CFF corresponds linearly with the log of retinal illumination?

The speed at which the visual system can detect flickering light is known as the critical flicker fusion (CFF) frequency. The Ferry-Porter Law describes the relationship between the frequency of flicker and the background illumination level. Specifically, it states that as the luminance level increases, the frequency at which a flickering light source appears to be steady (the CFF) also increases in a linear manner when plotted against the logarithm of the illumination.

This means that under conditions of varying retinal illumination, individuals can perceive flicker at higher frequencies with increased illumination, suggesting an adaptive response of the visual system. The linear correlation with the logarithm of illuminance highlights how our perception is finely tuned to changes in light, compensating for the vast range of luminance we encounter.

In contrast, the other laws, such as the Granit-Harper Law, focus on different aspects of visual perception relating to the intensity and integration of light rather than a linear relationship with logarithmic illumination. The Broca-Sulzer Effect pertains to the perception of brightness rather than flicker. The Brucke-Bartley Effect describes how brightness perception can change with the duration of light exposure. Each of these concepts plays a distinct role in understanding visual