Phi Phenomenon
The Phi Phenomenon is a Gestalt principle of movement perception. It happens when a series of still images are flashed on and off in succession. It has often been related to film and vidoe, but there are some people who say it is not the same as persistence of vision that is also refered to when speaking of film and video.
Some information relating to the illusion of motion and/or phenomena related to color and motion – synesthesia – after images- RGB color model –(addresses movement in color-VRsystems) computational models of Visual Perception (gaming) - The aperture problem in motion perception – beta movement (still image _ball from left to right) – phi phenomenon (cloud of background color) – magna phi –– “A typical explanation of persistence of vision went something like this: when the human eye is presented with a rapid succession of slightly different images, there is a brief period during which each image, after its disappearance, persists upon the retina, allowing that image to blend smoothly with the next image. Such an explanation might begin to account for a sense of constancy of the light source (flicker fusion), but it is, of course, a totally inadequate explanation of the illusion of motion in the cinema. The proposed fusion or blending of images could produce only the superimposition of successive views, as in Marcel Duchamp's painting "Nude Descending a Staircase" or a frame from Norman McLaren's Pas de Deux. The result would be a piling up of images, or at best a static collage of superimposed still pictures, not an illusion of motion. It is the obvious inadequacy of the explanation, coupled with its recurrence in film literature for almost a century, that arouses one's curiosity about the origins of the notion and the means by which it has been perpetuated.” (Anderson and Anderson, 1993)
The following are Flash animation examples of classic Phi Phenomenon
These next example are not typical examples of Phi, but if you look closely, you can see a trail of background color that follows each of the colored dots. This is very similar to the trail or ghost of the previous examples.