Talk:Joseph Plateau

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"Joseph Antoine Ferdinand Plateau (1801-1883), professor at the Ghent University (Belgium), became known as the blind genius, who did more than 40 years of scientific research whilst being blind. As the legend goes, he became blind because of too much looking into the sun, during his research into the functioning of the human eye. In reality he may have suffered from a temporary blindness in 1829 after looking into the sun for several seconds. However, it was only between 1841-1844 that he gradually became blind as the result of an infection of the iris.

Plateau proved, with a rotating drop of oil, that the earth is not really round, but a bit broader in the hips. He also did pioneering work on surface tension. And knew that soap bubbles always collide with four in one point, under an angle of 109°28’. Plateau remains most famous for his research on visual perception. As stated before, he invented the synthesis of movement. The point of departure for his research was the persistence of light images which some scientists had explored before him. Persistence of vision had been known to the ancient Egyptians, but in spite of the work of Isaac Newton and the Chevalier d’Arcy, it was not until 1824 that it was satisfactorily defined, by Peter Mark Roget, as the ability of the retina to retain an image of an object after its removal from the field of vision.(1)

The Phenakisticope Around 1827, Plateau tried to measure this persistence and found an average duration of 34/100 of a second. Today, we know that the persistence of light images is between 1/20 and 1/5 of a second. The difference between the two measurements is explained simply by the rudimentary nature of the instruments used by Plateau. In 1832, he came up with the idea of dividing a disk into sectors and of painting the same figure at the edge of the circumference of each of them. He then cut slots between these drawings, turned the painted side to face a mirror, spun the disk round an axis and looked through the slots. As he had expected, Plateau saw an immobile figure and one disk. The images were prevented from merging thanks to the slots of the disk that acted as a shutter.

Plateau then came up with an ingenious idea: “If, instead of having identical figures” he wrote, “we have them gradually go from one position to the other, and if the speed is high enough for these successive images to blend, but without interfering with each other, we will get the impression that each of these small figures gradually changes state…”. (2)

Plateau therefore drew different phases of the movement of a dancer doing a pirouette at the edge of the disk. The result was astounding as movement could now be created by rotating the disk. Plateau called his device “Phenakisticope” (3) (from the Greek for “deceitful view”). This was the first device to synthesise movement. Plateau painted some of his disks himself, but entrusted others to his brother-in-law, the Brussels painter Jean-Baptiste Madou. The Phenakisticope would rapidly leave the laboratory to become a prized toy and in the “Monde Littéraire” of 17 April 1853, Baudelaire published a text entitled “La Morale du joujou” (A Remarkable Toy) in which he lauded the virtues of this scientific toy: “The main drawback of these toys is that they are expensive. But they can provide entertainment for a long time and develop a taste for marvellous and surprising effects in a child’s mind.” Baudelaire then provided a detailed description of the Phenakisticope and of its “twenty identical dancing figures performing the same movements with fantastic precision”. (4)

Flanders International Film Festival - Ghent Each year again the Flanders International Film Festival Ghent, presents one or more Special Honorary Joseph Plateau Awards to a special guest whose achievements have earned him a special and distinct place in the history of international film making. This award, previously given to eminent guests such as André Delvaux, Robert Wise, Robert Altman, Elmer Bernstein, Shohei Imamura and Alain Resnais, is a token of the festival’s esteem and high regard of the recipient’s contribution to the 7th art and the festival’s gratitude that he has honored it with his presence. The award can furthermore be bestowed on a young person in mid-career, who may not be well known today, but whose talent and style have marked the industry. We expect that the careers of younger recipients will continue to blossom and add even greater distinction to their names in the future.

The award itself is a replica of professor Joseph Plateau’s Phenakisticope (see: [1]), the device he designed to illustrate his theory of the persistence of vision, which turned out to become the basic principle of the idea of “moving images”. Plateau invented the Phenakisticope, by which the illusion of motion could be created. _____________________

(1) However, it has since been shown that film images seem to move because the brain, and not the eye, is accepting stimuli which it is incapable of perceiving as separate. The brain has a perception threshold, below which images exposed to it will appear as continuous and film’s speed of 24 frames per second is below that threshold. Persistence of vision or flicker fusion prevents us from seeing lines between each frame, while the phi phenomenon or stroboscopic effect, analysed between 1912 and 1916 by the psychologist Max Wertheimer, provides a mental bridge between the frames to permit us to see a series of static images as a single continuous movement. Cinema is, therefore, the first art form to rely solely on psycho-perceptual illusions generated by a machine. (2) J. Plateau, “Sur un nouveau genre d’illusions d’optique” in Correspondance mathématique et physique, Brussels, n° 6, 1832. (3) It was never explained why Plateau dropped the “s” from “scope”. (4) Baudelaire, “Morale du joujou” in L’Art Romantique”, La Guilde du Livre, Lausanne, 1950, P. 142"

I suspect a copyright violation and even if there is none, the information should be integrated in the existing text. - Karl Stas 19:50, 8 December 2005 (UTC)