Movie projector
A movie projector is an opto-mechanical device for displaying motion picture film by projecting it onto a screen. Most of the optical and mechanical elements, except for the illumination and sound devices, are present in movie cameras. Modern movie projectors are specially built video projectors.
Many projectors are specific to a particular film gauge and not all movie projectors are film projectors since the use of film is required.
Predecessors
The main precursor to the movie projector was the magic lantern. In its most common setup it had a concave mirror behind a light source to help direct as much light as possible through a painted glass picture slide and a lens, out of the lantern onto a screen. Simple mechanics to have the painted images moving were probably implemented since Christiaan Huygens introduced the apparatus around 1659. Initially, candles and oil lamps were used, but other light sources, such as the argand lamp and limelight were usually adopted soon after their introduction. Magic lantern presentations may often have had relatively small audiences, but the very popular phantasmagoria and dissolving views shows were usually performed in proper theatres, large tents or especially converted spaces with plenty seats.Both Joseph Plateau and Simon Stampfer thought of lantern projection when they independently introduced stroboscopic animation in 1833 with a stroboscopic disc, but neither of them intended to work on projection themselves.
The oldest known successful screenings of stroboscopic animation were performed by Ludwig Döbler in 1847 in Vienna and taken on a tour to several large European cities for over a year. His Phantaskop had a front with separate lenses for each of the 12 pictures on a disc and two separate lenses were cranked around to direct light through the pictures.
Wordsworth Donisthorpe patented ideas for a cinematographic film camera and a film presentation system in 1876. In reply to the introduction of the phonograph and a magazine's suggestion that it could be combined with projection of stereoscopic photography, Donisthorpe stated that he could do even better and announce that he would present such images in motion. His original Kinesigraph camera gave unsatisfactory results. He had better results with a new camera in 1889 but never seems to have been successful in projecting his movies.
Eadweard Muybridge developed his Zoopraxiscope in 1879 and gave many lectures with the machine from 1880 to 1894. It projected images from rotating glass disks. The images were initially painted onto the glass, as silhouettes. A second series of discs, made in 1892–94, used outline drawings printed onto the discs photographically, then colored by hand.
Ottomar Anschütz developed his first Electrotachyscope in 1886. For each scene, 24 glass plates with chronophotographic images were attached to the edge of a large rotating wheel and thrown on a small opal-glass screen by very short synchronized flashes from a Geissler tube. He demonstrated his photographic motion from March 1887 until at least January 1890 to circa 4 or 5 people at a time, in Berlin, other large German cities, Brussels, Florence, Saint Petersburg, New York, Boston and Philadelphia. Between 1890 and 1894 he concentrated on the exploitation of an automatic coin-operated version that was an inspiration for Edison Company's Kinetoscope. From 28 November 1894 to at least May 1895 he projected his recordings from two intermittently rotating discs, mostly in 300-seat halls, in several German cities. During circa 5 weeks of screenings at the old Berlin Reichstag in February and March 1895, circa 7.000 paying visitors came to see the show.
In 1886, Louis Le Prince applied for a US patent for a 16-lens device that combined a motion picture camera with a projector. In 1888, he used an updated version of his camera to film the motion picture Roundhay Garden Scene and other scenes. The pictures were privately exhibited in Hunslet. After investing much time, effort and means in a slow and troublesome development of a definitive system, Le Prince eventually seemed satisfied with the result and had a demonstration screening scheduled in New York in 1890. However, he went missing after boarding a train in France and was declared dead in 1897. His widow and son managed to draw attention to Le Prince's work and eventually he came to be regarded as the true inventor of film.
After years of development, Edison eventually introduced the coin-operated peep-box Kinetoscope movie viewer in 1893, mostly in dedicated parlors. He believed this was a commercially much more viable system than projection in theatres. Many other film pioneers found chances to study the technology of the kinetoscope and further developed it for their own movie projection systems.
The Eidoloscope, devised by Eugene Augustin Lauste for the Latham family, was demonstrated for members of the press on 21 April 1895 and opened to the paying public on May 20, in a lower Broadway store with films of the Griffo-Barnett prize boxing fight, taken from Madison Square Garden's roof on 4 May. It was the first commercial projection.
Nicholas Power opened a repair shop for Edison projectors, studied them, and developed one of the earliest and most successful projectors without excessive flicker.
Max and Emil Skladanowsky projected motion pictures with their Bioscop, a flicker-free duplex construction, from 1 to 31 November 1895. They started to tour with their motion pictures, but after catching the second presentation of the Cinématographe Lumière in Paris on 28 December 1895, they seemed to choose not to compete. They still presented their motion pictures in several European cities until March 1897, but eventually the Bioscop had to be retired as a commercial failure.
In Lyon, Louis and Auguste Lumière perfected the Cinématographe, a system that took, printed, and projected film. In late 1895 in Paris, father Antoine Lumière began exhibitions of projected films before the paying public, beginning the general conversion of the medium to projection. They quickly became Europe's main producers with their actualités like Workers Leaving the Lumière Factory and comic vignettes like The Sprinkler Sprinkled. Even Edison, joined the trend with the Vitascope, a modified Jenkins' Phantoscope, within less than six months.
In the 1910s, a new consumer commodity was introduced aiming at familial activity, the silent home cinema. Hand-cranked tinplate toy movie projectors, also called vintage projectors, were used taking standard 35 mm 8 perforation silent cinema films.
Digital projectors
In 1999, digital cinema projectors were being tried out in some movie theaters. These early projectors played the movie stored on a computer, and sent to the projector electronically. Due to their relatively low resolution compared to later digital cinema systems, the images at the time had visible pixels. By 2006, the advent of much higher 4K resolution digital projection reduced pixel visibility. The systems became more compact over time. By 2009, movie theaters started replacing film projectors with digital projectors. In 2013, it was estimated that 92% of movie theaters in the United States had converted to digital, with 8% still playing film. In 2014, numerous popular filmmakers—including Quentin Tarantino and Christopher Nolan—lobbied large studios to commit to purchase a minimum amount of 35 mm film from Kodak. The decision ensured that Kodak's 35 mm film production would continue for several years.Although usually more expensive than film projectors, high-resolution digital projectors offer many advantages over traditional film units. For example, digital projectors contain no moving parts except fans, can be operated remotely, are relatively compact and have no film to break, scratch or change reels of. They also allow for much easier, less expensive, and more reliable storage and distribution of content. All-electronic distribution eliminates all physical media shipments. There is also the ability to display live broadcasts in theaters equipped to do so.
Physiology
The illusion of motion in projected films is a stroboscopic effect that has conventionally been attributed to persistence of vision and later often to beta movement and the phi phenomenon known from Gestalt psychology. The exact neurological principles are not yet entirely clear, but the retina, nerves and brain create the impression of apparent movement when presented with a rapid sequence of near-identical still images and interruptions that go unnoticed. A critical part of understanding this visual perception phenomenon is that the eye is not a camera, i.e.: there is no frame rate for the human eye or brain. Instead, the eye-brain system has a combination of motion detectors, detail detectors and pattern detectors, the outputs of all of which are combined to create the visual experience.The frequency at which flicker becomes invisible is called the flicker fusion threshold, and is dependent on the level of illumination and the condition of the eyes of the viewer. Generally, the frame rate of 16 frames per second is regarded as the lowest frequency at which continuous motion is perceived by humans. This threshold varies across different species; a higher proportion of rod cells in the retina will create a higher threshold level. Because the eye and brain have no fixed capture rate, this is an elastic limit, so different viewers can be more or less sensitive in perceiving frame rates.
It is possible to view the black space between frames and the passing of the shutter by rapidly blinking one's eyes at a certain rate. If done fast enough, the viewer will be able to randomly trap the darkness between frames or the motion of the shutter. This will not work with cathode-ray tube displays, due to the persistence of the phosphors, nor with LCD or DLP light projectors, because they refresh the image instantly with no blackout intervals as with traditional film projectors.
Silent films usually were not projected at constant speeds, but could vary throughout the show because projectors were hand-cranked at the discretion of the projectionist, often following some notes provided by the distributor. When the electric motor supplanted hand cranking in both movie cameras and projectors, a more uniform frame rate became possible. Speeds ranged from about 18 frame/s on upsometimes even faster than modern sound film speed.
16 frame/sthough sometimes used as a camera shooting speedwas inadvisable for projection, due to the risk of the nitrate-base prints catching fire in the projector. Nitrate film stock began to be replaced by cellulose triacetate in 1948. A nitrate film fire and its devastating effect is featured in Cinema Paradiso, a fictional film which partly revolves around a projectionist and his apprentice.
The birth of sound film created a need for a steady playback rate to prevent dialog and music from changing pitch and distracting the audience. Virtually all film projectors in commercial movie theaters project at a constant speed of 24 frame/s. This speed was chosen for both financial and technical reasons. A higher frame rate produces a better-looking picture but costs more as film stock is consumed faster. When Warner Bros. and Western Electric were trying to find the ideal compromise projection speed for the new sound pictures, Western Electric went to the Warner Theater in Los Angeles and noted the average speed at which films were projected there. They set that as the sound speed at which a satisfactory reproduction and amplification of sound could be conducted.
There are some specialist formats that project at higher rates—60 frames per second for Showscan and 48 for Maxivision. The Hobbit was shot at 48 frames per second and projected at the higher frame rate at specially equipped theaters.
Each frame of regular 24 fps movies are shown twice or more in a process called double-shuttering to reduce flicker.