Monday’s Google Doodle shines a light on the work of physicist Joseph Antonine Ferdinand Plateau, who discovered that a series of still pictures could create the illusion of movement.
If you’ve seen a movie or watched an online video lately, you owe the experience to Plateau’s 1832 invention, the phenakistiscope (whose name is a rough Greek translation of “to cheat the eye). The phenakistiscope gave 19th-century viewers their first taste of animation, but it was a pretty simple device: two cardboard discs, designed to spin in opposite directions. One disc showed a series of images, like still shots of a person dancing or walking. The other had rectangular windows. If the discs spun at the same speed, the series of still images would pass through each “window” so quickly that it looked like a single moving image — albeit with a flickering effect. Kids’ flip-book animations work on a similar principle, and so do more complex cartoons and even video. You’re not really seeing a moving image; you’re seeing a rapid succession of still images, which tricks your eyes into thinking they’re looking at motion.
The phenakistiscope’s name took longer to say than one of its animations took to watch; the device could display only a short, repeating animation — so a walking person, for example, would take the same step or two over and over. In other words, Plateau invented the ancestor of the modern GIF. In some ways, it was an idea ahead of its time; people took almost another two centuries to learn to use those short “moving” images to react to each other’s online comments.
Those flickering, short cartoons were the practical application of Plateau’s research on the physics of human vision. As a PhD student, he focused on how light produces images on the retina (a layer of light-sensitive cells at the back of the eye, which sends signals to the optic nerve). He found that the eye perceives images based on the color and intensity of the light that reaches the retina, as well as how long the retina is exposed to the light. Based on those findings, Plateau realized that stroboscopic images could create an optical illusion of movement.
But Plateau’s fascination with light and vision may have cost him his own vision. The optics researcher went blind late in life, although he continued his research in experimental physics with assistance from his son Felix Plateau and his son-in-law and biographer Gustaaf Van der Mensbrugghe. He blamed the loss on an experiment during his days as a doctoral student, when the otherwise brilliant physicist decided it would be a good idea to stare directly at the sun for 25 seconds. The resulting retinal damage may eventually have degraded Plateau’s vision, although doctors have since suggested that he actually suffered from a totally unrelated case of uveitis (an inflammation of the pigmented layer of the eye that includes the iris).
Plateau died in 1883.