Persistence of Vision Explained: What Is Persistence of Vision?

Persistence of vision is an optical illusion where the human eye perceives the continued presence of an image after it has disappeared from view. Also known as retinal persistence, this optical effect was described by English-Swiss physicist Peter Mark Roget in the nineteenth century.

In the motion picture industry, animators have combined the basic principle of persistence of vision with the phi phenomenon, which postulates that showing still images in rapid succession can create the illusion of movement—as in a flipbook, for example. To this day, filmmakers rely on these phenomena to create the illusion of motion in animated films.

Persistence of vision works by exploiting quirks of the human retina, visual cortex, and sensory memory. Studies show that visual stimuli linger in a human's perception for a very brief period after those stimuli end. Some theorists describe these lingering visuals as positive afterimages.

Over the course of many generations, inventors have seized on both the persistence of vision and the phi phenomenon to create optical toys, animations, and films. Nineteenth-century inventions like the phenakistoscope were among the first to exploit persistence of vision and the phi phenomenon to create a false sense of moving objects.

A cylindrical update on the phenakistoscope called the zoetrope saw broad popularity throughout the century. Even simpler optical toys like the thaumatrope and the kaleidoscopic colour-top created similar optical illusions. By the twentieth century, the new medium of film swept through the developed world, and motion pictures took the persistence of vision to exciting new ends.

The persistence of vision is used in animated films to trick the human eye into seeing moving pictures. Most film cinematography captures twenty-four frames of film (or the digital equivalent) per second. However, research suggests that the human eye struggles to differentiate between more than twelve images in a single second.

This means animators can use one still image for every two frames of twenty-four-frames-per-second film. The human eye will accept this as believable motion. However, anything fewer than twelve images per second will disrupt the optical illusion of fluid motion and animations will appear jittery.

To create faster, more fluid motion, animators use one still image for every frame of film. This effectively places twenty-four separate images in front of the human eye in the course of one second. This matches the number of images in live-action filmmaking, and it comes across as completely believable to the human eye.

Become a better filmmaker with the MasterClass Annual Membership. Gain access to exclusive video lessons taught by the world’s best, including James Cameron, Spike Lee, David Lynch, Shonda Rhimes, Jodie Foster, Martin Scorsese, and more.