Persistence of vision traditionally refers to the optical illusion that occurs when visual perception of an object does not cease for some time after the rays of light proceeding from it have ceased to enter the eye. The illusion has also been described as "retinal persistence", "persistence of impressions", simply "persistence" and other variations. According to this definition, the illusion would be the same as, or very similar to positive afterimages.
"Persistence of vision" can also be understood to mean the same as "flicker fusion", the effect that vision seems to persist continuously when a stream of light is repeatedly interrupted for very brief instances and thus enters the eyes intermittently.
Since its introduction, the term "persistence of vision" has been believed to be the explanation for motion perception in optical toys like the phenakistiscope and the zoetrope, and later in cinema. However, this theory has been disputed even before cinema was introduced in 1895. If "persistence of vision" is explained as "flicker fusion", it can be seen as an important factor in the illusion of moving pictures in cinema and related optical toys, but not as its sole principle.
Early descriptions of the illusion often attributed the effect purely to imperfections of the eye, particularly of the retina. Nerves and parts of the brain later became part of explanations.
Some natural phenomena and the principles of some optical toys have been attributed to the persistence of vision effect. Patrick d'Arcy recognised the effect in "the luminous ring that we see by turning a torch quickly, the fire wheels in the fireworks, the flattened spindle shape we see in a vibrating cord, the continuous circle we see in a cogwheel that turns with speed". Basically everything that resembles motion blur seen in fast moving objects could be regarded as "persistence of vision".
The fact that a glowing coal appears as a line of light when it is moved around quickly has often been used to illustrate the idea of persistence of vision. It is known as the "sparkler's trail effect", named after the trail that appears when a sparkler is moved around quickly.
The effect has been applied in the arts by writing or drawing with a light source recorded by a camera with a long exposure time.
Colors on spinning tops or rotating wheels mix together if the motion is too fast to register the details. A colored dot then appears as a circle and one line can make the whole surface appear in one uniform hue.
The Newton disc optically mixes wedges of Isaac Newton's primary colors into one (off-)white surface when it spins fast.
In April 1825 the first Thaumatrope was published by W. Phillips (in anonymous association with John Ayrton Paris). The fact that the image of one side of the disc seems to blend with the image of the other side when it is looked at while it is twirled very fast, is often used as an illustration of persistence of vision.
In April 1858 John Gorham patented his Kaleidoscopic colour-top. This is a top on which two small discs are placed, usually one with colors and a black one with cut-out patterns. When the discs spin and the top disc is retarded into regular jerky motions the toy exhibits "beautiful forms which are similar to those of the kaleidoscope" with multiplied colours. Gorham described how the colours appear mixed on the spinning top "from the duration of successive impressions on the retina". Gorham founded the principle on "the well-known experiment of whirling a stick, ignited at one end" (a.k.a. the sparkler's trail effect).
A pencil or another rigid straight line can appear as bending and becoming rubbery when it is wiggled fast enough between fingers, or otherwise undergoing rigid motion.
Persistence of vision has been discarded as sole cause of the illusion. It is thought that the eye movements of the observer fail to track the motions of features of the object.
This effect is known as an entertaining "magic" trick for children.
The term "persistence of vision display" or "POV display" has been used for LED display devices that compose images by displaying one spatial portion at a time in rapid succession (for example, one column of pixels every few milliseconds). A two-dimensional POV display is often accomplished by means of rapidly moving a single row of LEDs along a linear or circular path. The effect is that the image is perceived as a whole by the viewer as long as the entire path is completed during the visual persistence time of the human eye. A further effect is often to give the illusion of the image floating in mid-air. A three-dimensional POV display is often constructed using a 2D grid of LEDs which is swept or rotated through a volume. POV display devices can be used in combination with long camera exposures to produce light writing.
A common example of this can be seen in the use of bicycle wheel lights that produce patterns.
Although the theory of persistence of vision as the (main) reason we see film as motion has been disproved since 1912, film historians have persisted in citing the theory as well as historical references to afterimages and similar illusions. The following developments are relevant to that story.
Aristotle (384–322 BCE) noted that the image of the sun remained in his vision after he stopped looking at it.
The discovery of persistence of vision is sometimes attributed to the Roman poet Lucretius (c. 15 October 99 BCE – c. 55 BCE), although he only mentions it in connection with images seen in a dream.
Around 165 CE Ptolemy described in his book Optics a rotating potter's wheel with different colors on it. He noted how the different colors of sectors mixed together into one color and how dots appeared as circles when the wheel was spinning very fast. When lines are drawn across the axis of the disc they make the whole surface appear to be of a uniform color. "The visual impression that is created in the first revolution is invariably followed by repeated instances that subsequently produce an identical impression. This also happens in the case of shooting stars, whose light seems distended on account of their speed of motion, all according to the amount of perceptible distance it passes along with the sensible impression that arises in the visual faculty."
Porphyry (circa 243–305) in his commentary on Ptolemy's Harmonics describes how the senses are not stable but confused and inaccurate. Certain intervals between repeated impressions are not detected. A white or black spot on a spinning cone (or top) appears as a circle of that color and a line on the top makes the whole surface appear in that color. "Because of the swiftness of the movement we receive the impression of the line on every part of the cone as the line moves."
In the 11th century Ibn al-Haytam, who was familiar with Ptolemy's writings, described how colored lines on a spinning top could not be discerned as different colors but appeared as one new color composed of all of the colors of the lines. He deducted that sight needs some time to discern a color. al-Haytam also noted that the top appeared motionless when spun extremely quick "for none of its points remains fixed in the same spot for any perceptible time".
Leonardo da Vinci wrote in a notebook: "Every body that moves rapidly seems to colour its path with the impression of its hue. The truth of this proposition is seen from experience; thus when the lightning moves among dark clouds the speed of its sinuous flight makes its whole course resemble a luminous snake. So in like manner if you wave a lighted brand its whole course will seem a ring of flame. This is because the organ of perception acts more rapidly than the judgment."
Isaac Newton (1642–1726/27) purportedly demonstrated how white light is a combination of different colors with a rotating disc with color segments. When spinning fast the colors seem to blend and appear as white (or rather an off-white light hue). In his 1704 book Opticks he described a machine with prisms, a lens and a large moving comb with teeth causing alternating colors to be projected successively. If this was done quickly enough, the alternating colours could no longer be perceived separately but were seen as white. Newton compared its principle to the sparkler's trail effect: a gyrating burning coal could appear as a circle of fire because "the sensation of the coal in the several places of that circle remains impress'd on the sensorium, until the coal return again to the same place."
In 1768 Patrick d'Arcy (1725-1779) reported how he had measured a duration of 0,13 seconds for one full rotation of a burning coal while it was seen as a full circle of light. He registered multiple rotations with a purpose-built machine in his garden and with the collaboration of an observer who had better eyesight. D'Arcy suspected that the duration may differ between different observers, light intensities of spinning objects, colours and viewing distances. He planned further experiments to determine such possible differences, but no results seem to have been published.
In 1821 the Quarterly Journal of Science, Literature, and The Arts published a "letter to the editor" with the title Account of an Optical Deception. It was dated Dec. 1, 1820 and attributed to "J.M.", possibly publisher/editor John Murray himself. The author noted that the spokes of a rotating wheel seen through fence slats appeared with peculiar curvatures (see picture). The letter concluded: "The general principles on which this deception is based will immediately occur to your mathematical readers, but a perfect demonstration will probably prove less easy than it appears on first sight". Four years later Peter Mark Roget offered an explanation when reading at the Royal Society on December 9, 1824. He added: “It is also to be noticed that, however rapidly the wheel revolves, each individual spoke, during the moment it is viewed, appears to be at rest." Roget claimed that the illusion is due to the fact “that an impression made by a pencil of rays on the retina, if sufficiently vivid, will remain for a certain time after the cause has ceased.” He also provided mathematical details about the appearing curvatures.
As a university student Joseph Plateau noticed in some of his early experiments that when looking from a small distance at two concentric cogwheels which turned fast in opposite directions, it produced the optical illusion of a motionless wheel. He later read Peter Mark Roget's 1824 article and decided to investigate the phenomenon further. He published his findings in Correspondance Mathématique et Physique in 1828 and 1830. In 1829 Plateau presented his then unnamed anorthoscope in his doctoral thesis Sur quelques propriétés des impressions produites par la lumière sur l'organe de la vue. The anorthoscope was a disc with an anamorphic picture that could be viewed as a clear immobile image when the disc was rotated and seen through the four radial slits of a counter-rotating disc. The discs could also be translucent and lit from behind through the slits of the counter-rotating disc.
On December 10, 1830 scientist Michael Faraday presented a paper at the Royal Institution of Great Britain, titled On a Peculiar Class of Optical Deceptions, about the optical illusions that could be found in rotating wheels. He referred to Roget's paper and described his relating new findings. Much was similar to what Plateau had already published and Faraday later acknowledged this. However, a unique part of Faraday's experiments concerned turning wheels in front of a mirror and this inspired Plateau with the idea for new illusions. In July 1832 Plateau sent a letter to Faraday and added an experimental circle that produced a “completely immobile image of a little, perfectly regular horse” when rotated in front of a mirror. After several attempts and many difficulties Plateau managed to animate the figures between the slits in a disc when he constructed the first effective model of the phénakisticope in November or December 1832 . Plateau published his then unnamed invention in a January 20, 1833 letter to Correspondance Mathématique et Physique.
Simon Stampfer independently and almost simultaneously invented his very similar Stroboscopischen Scheiben oder optischen Zauberscheiben (stroboscopic discs or optical magic discs) soon after he read about Faraday's findings in December 1832.
Stampfer also mentioned several possible variations of his stroboscopic invention, including a cylinder (similar to the later zoetrope) as well as a long, looped strip of paper or canvas stretched around two parallel rollers (somewhat similar to film) and a theater-like frame (much like the later praxinoscope). In January 1834, William George Horner also suggested a cylindrical variation of Plateau's phénakisticope, but he did not manage to publish a working version. William Ensign Lincoln invented the definitive zoetrope with exchangeable animation strips in 1865 and had it published by Milton Bradley and Co. in December 1866.
The idea that the motion effects in so-called "optical toys", like the phénakisticope and the zoetrope, is caused by images lingering on the retina was questioned in an 1868 article by William Benjamin Carpenter. He suggested that the illusion was "rather a mental than a retinal phenomenon".
Narrowly defined, the theory of persistence of vision is the belief that human perception of motion (brain centered) is the result of persistence of vision (eye centered). That version of the theory was discarded well before the invention of film and also disproved in the context of film in 1912 by Wertheimer but persists in citations in many classic and modern film-theory texts. A more plausible theory to explain motion perception (at least on a descriptive level) are two distinct perceptual illusions: phi phenomenon and beta movement.
A visual form of memory known as iconic memory has been described as the cause of this phenomenon. Although psychologists and physiologists have rejected the relevance of this theory to film viewership, film academics and theorists generally have not. Some scientists nowadays consider the entire theory of iconic memory a myth.
When contrasting the theory of persistence of vision with that of phi phenomena, an understanding emerges that the eye is not a camera and does not see in frames per second. In other words, vision is not as simple as light registering on a medium, since the brain has to make sense of the visual data the eye provides and construct a coherent picture of reality. Joseph Anderson and Barbara Fisher argue that the phi phenomena privileges a more constructionist approach to the cinema (David Bordwell, Noël Carroll, Kirstin Thompson) whereas the persistence of vision privileges a realist approach (André Bazin, Christian Metz, Jean-Louis Baudry).
Allen William Mark (Doc) Coombs (23 October 1911 – 30 January 1995) was a British electronics engineer at the Post Office Research Station, Dollis Hill. He was one of the principal designers of the Mark II or production version of the Colossus computer used at Bletchley Park for codebreaking in World War II, and took over leadership of the project when Tommy Flowers moved on to other projects.
Later, he headed the scientific side of R14, the division working on optical character recognition for postal mechanisation, which moved to the new BT Research Centre at Martlesham in Suffolk. His work on pattern recognition led to the development of an early postcode-reading machine.
He frequently lectured on pattern recognition using the concept of multi-dimensional space, and the 'caltrop', and would demonstrate the presence of feature-detection in the human visual system by means of a flash gun, the persistence of vision in the audience leading them to observe disintegration of a character fragment by fragment. 'Doc' Coombs was notable for a facial 'tic', which gave him something of the appearance of the 'mad professor', and these days would probably be classed under Tourette's syndrome.Intermittent mechanism
The intermittent mechanism or intermittent movement is the device by which film is regularly advanced and then held in place for a brief duration of time in a movie camera or movie projector. This is in contrast to a continuous mechanism, whereby the film is constantly in motion and the image is held steady by optical or electronic methods. The reason the intermittent mechanism "works" for the viewer is because of a phenomenon called persistence of vision.John Varley (author)
John Herbert Varley (born August 9, 1947) is an American science fiction writer.Kenny Hunter
Kenny Hunter (born 1962) is a Scottish sculptor. He lives and works in Edinburgh. Between 2015 - 2018, he was Programme Director of Sculpture at Edinburgh College of Art where he now continues to work part-time as a lecturer in Fine Art, Sculpture.Mercy Point
Mercy Point is an American science fiction medical drama, created by Trey Callaway, David Simkins, and Milo Frank, which originally aired for one season on United Paramount Network (UPN) from October 6, 1998, to July 15, 1999. With an ensemble cast led by Joe Morton, Maria del Mar, Alexandra Wilson, Brian McNamara, Salli Richardson, Julia Pennington, Gay Thomas, Jordan Lund, and Joe Spano, the series focuses on the doctors and nurses in a 23rd-century hospital space station located in deep space. The executive producers were Trey Callaway, Michael Katleman, Lee David Zlotoff, Joe Voci, and Scott Sanders.
Callaway adapted Mercy Point from his original screenplay, "Nightingale One". It was picked up by Mandalay Television, and the concept was eventually revised as a television project and renamed Mercy Point; production on the film project had ended due to the poor commercial performance of the 1997 film Starship Troopers. The television show was part of a three-million-dollar deal between Mandalay and Columbia TriStar Television to produce 200 hours of material. It was filmed in Vancouver to reduce production costs, the hospital sets being constructed on a series of sound stages. Director Joe Napolitano has praised the show for its use of a complete set to allow for more intricate directing. Despite Callaway envisioning Mercy Point as a companion to Star Trek: Voyager, it was paired with Moesha and Clueless as its lead-in on Tuesday nights. Initially focused on ethical and medical cases, the show's storylines gradually shifted toward relating the characters' personal relationships, to better fit UPN's primarily teen demographic.
Mercy Point was placed on hiatus after only three episodes were aired, and was replaced by the reality television series America's Greatest Pets and the sitcom Reunited. The show suffered from low ratings, with an average of two million viewers. The final four episodes of the series were broadcast in two 2-hour blocks on Thursday nights in July 1999. It has never been released on DVD or Blu-ray, or made available on online-streaming services. Critical response to Mercy Point was mixed; some commentators praised its characterization and use of science-fiction elements, while others found it to be uninteresting and unoriginal. Callaway stated that he had the potential story arcs for the full first season already planned before the show's cancellation.Newton disc
The Newton disc is a well-known physics experiment with a rotating disc with segments in different colors (usually Newton's primary colors: red, orange, yellow, green, blue, indigo and violet) appearing as white (or off-white or gray) when it spins very fast.
This type of mix of light stimuli is called temporal optical mixing, a version of additive-averaging mixing. The concept that human visual perception cannot distinguish details of high-speed movements is popularly known as persistence of vision.
The disc is named after Isaac Newton. Although he published a circular diagram with segments for the primary colors that he had discovered, it is uncertain whether he actually ever used a spinning disc to demonstrate the principles of light (see below).
Transparent variations for magic lantern projection have been produced.POV-Ray
The Persistence of Vision Ray Tracer, or POV-Ray, is a ray tracing program which generates images from a text-based scene description, and is available for a variety of computer platforms. It was originally based on DKBTrace, written by David Kirk Buck and Aaron A. Collins for the Amiga computers. There are also influences from the earlier Polyray raytracer contributed by its author Alexander Enzmann. POV-Ray is free and open-source software with the source code available under the AGPLv3.POV (album)
POV is the ninth studio album by the rock group Utopia, released in 1985. It peaked at #161 on the Billboard 200 charts. Except for live reunion albums and compilations, this was the last album recorded by Utopia, and Rundgren's final work under the Utopia banner until the group reformed for a Japanese tour in 1992.
The ambiguous acronym title is given four possible explanations on the back cover of the album, standing variously for "Price of Victory", "Pillar of Virtue", "Point of View" or "Persistence of Vision". The front cover photo depicts the band dressed in quasi-military costumes and looking at a star map, while in the background the giant "Pharaoh" mask (a stage prop from their mid-1970s "RA" tour) can be seen. The album layout also reflects Rundgren's interest in computers and information technology and incorporates elements adapted from the 'window' design used in the Apple Macintosh operating system of the mid-1980s.Persistence of Vision (film)
Persistence of Vision is a 2012 documentary film based on Richard Williams' experiences trying to get The Thief and the Cobbler made. The film was directed by filmmaker Kevin Schreck. Its tagline is, "the untold story of the greatest animated film never made." The film premiered in Canada on 4 October 2012 at the Vancouver International Film Festival.Persistence of vision (disambiguation)
Persistence of vision is the optical illusion that occurs when visual perception of an object does not cease for some time after the rays of light proceeding from it have ceased to enter the eye.
Persistence of Vision may also refer to:
Persistence of Vision (Star Trek: Voyager), 8th episode of 2nd season of Star Trek: Voyager
Persistence of Vision Raytracer, cross-platform freeware ray tracing program
Persistence of Vision (film), a documentary film based on Richard Williams' experiences trying to make the animated film The Thief and the Cobbler
The Persistence of Vision (collection), a science fiction collection by John Varley
The Persistence of Vision (short story), 1978 Hugo and Nebula-winning novella of the collectionPhi phenomenon
The phi phenomenon is the optical illusion of perceiving a series of still images, when viewed in rapid succession, as continuous motion. Max Wertheimer, one of the three founders of Gestalt psychology, defined this phenomenon in 1912. The phi phenomenon and persistence of vision together formed the foundation of Hugo Münsterberg's theory of film and are part of the process of motion perception.
The phi phenomenon is similar to beta movement in that both cause sensation of movement. However, the phi phenomenon is an apparent movement caused by luminous impulses in sequence, whereas beta movement is an apparent movement caused by luminous stationary impulses.Pseudorealism
Pseudorealism, also spelled pseudo-realism, is a term used in a variety of discourses connoting artistic and dramatic techniques, or work of art, film and literature perceived as superficial, not-real, or non-realistic. By definition, the term is highly subjective.The term pseudo-realism has been used to describe a certain type of cultural commodities such as film productions and TV programmes which portray everyday life in excessively realistic detail in order to achieve greater impact on viewers.Following the great shift towards expressionism in painting, André Bazin used the word pseudoreal in reference to mechanical means which freed the plastic arts from the drive toward 'unachievable likeness'. Meanwhile, photorealistic CGI animation and 3D computer graphics used today have become indistinguishable from cine-photography. In that regard, the special effects augmenting feature film through photographic deception of the eye have gained an entirely different dimension. Computer generated imagery and 3D animation are used not only to bolster reality based images but also to create imaginary worlds.
We understand the CGI feature film to be an image of pseudorealism in Bazin’s terms – a fundamental deception of the eye. Of course the cinema itself in whatever incarnation involves a deception of the eye, that of the ‘persistence of vision’ effect. Though things appear to exist and have causal properties, they are the product of man-made parameters. — David Surman, "CGI Animation: Pseudorealism, Perception and Possible Worlds"
Christopher Hitchens equates pseudo-realism with Socialist realism of the Stalinist era as exposed by Orwell. Others, invoke the old pseudo-real traditions of Indian film with no negative characters.San Francisco International Film Festival
San Francisco International Film Festival (abbreviated as SFIFF) is among the longest running film festivals in the Americas. Organized by the San Francisco Film Society, the International is held each spring for two weeks, presenting around 200 films from over 50 countries annually. The Festival highlights current trends in international film and video production with an emphasis on work that has not yet secured U.S. distribution. Since its inception, the International has grown to serve over 70,000 patrons, with screenings held in San Francisco and Berkeley.In March 2014, Noah Cowan, former executive director of the Toronto International Film Festival, became executive director of the SFFS and SFIFF, replacing Ted Hope. Prior to Hope, the festival was briefly headed by Bingham Ray, who served as SFFS executive director until his death after only ten weeks on the job in January 2012. Graham Leggat became the executive director of the San Francisco Film Society on October 17, 2005. The Scottish-born Leggat died on August 25, 2011 from cancer, aged 51.SFIFF is currently programmed by SFFS Director of Programming Rachel Rosen, Programmer Rod Armstrong, Golden Gate Awards Manager Audrey Chang, and Programming Coordinator Joseph Flores.The 59th San Francisco International Film Festival took place from April 21 to May 5, 2016 at venues throughout the Bay Area.Thaumatrope
A thaumatrope is an optical toy that was popular in the 19th century. A disk with a picture on each side is attached to two pieces of string. When the strings are twirled quickly between the fingers the two pictures appear to blend into one due to the persistence of vision.
Examples of common thaumatrope pictures include a bare tree on one side of the disk, and its leaves on the other, or a bird on one side and a cage on the other. Many classic thaumatropes also included riddles or short poems, with one line on each side.
Thaumatropes can provide an illusion of motion with the two sides of the disc each depicting a different phase of the motion, but no examples are known to have been produced until long after the introduction of the first widespread animation device: the phénakistiscope.
Thaumatropes are often seen as important antecedents of motion pictures and in particular of animation. This is partly due to many film historians' belief that the associated theory of persistence of vision explains the physiological basis for movies, although this was disproved in 1912.The Persistence of Vision (collection)
The Persistence of Vision is a collection of science fiction stories by American writer John Varley.
The collection was also published in the United Kingdom under the title In the Hall of the Martian Kings.The Persistence of Vision (short story)
"The Persistence of Vision" is a science fiction novella by American writer John Varley. It won both the Hugo and Nebula awards for best novella in 1979. It was included in the anthology of the same name and in The John Varley Reader.