Intermittent Mechanism
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Intermittent Mechanism
{{short description, Device by which motion picture film is advanced An intermittent mechanism or intermittent movement is a device or movement which regularly advances an object, web, or plastic film and then holds it in place. This process is commonly used in industry and manufacturing. This motion is critical to the use of film 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. History Intermittent mechanisms were first used in sewing machines, in order for the fabric to be fed through correctly - ensuring it is stationary as each stitch is made, while moving the required distance between stitches. Methods used The intermittent mechanism must be employed in concert with a rotating shutter which blocks light transmitt ...
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Geneva Mechanism 6spoke Animation
, neighboring_municipalities= Carouge, Chêne-Bougeries, Cologny, Lancy, Grand-Saconnex, Pregny-Chambésy, Vernier, Veyrier , website = https://www.geneve.ch/ Geneva ( ; french: Genève ) frp, Genèva ; german: link=no, Genf ; it, Ginevra ; rm, Genevra is the second-most populous city in Switzerland (after Zürich) and the most populous city of Romandy, the French-speaking part of Switzerland. Situated in the south west of the country, where the Rhône exits Lake Geneva, it is the capital of the Republic and Canton of Geneva. The city of Geneva () had a population 201,818 in 2019 (Jan. estimate) within its small municipal territory of , but the Canton of Geneva (the city and its closest Swiss suburbs and exurbs) had a population of 499,480 (Jan. 2019 estimate) over , and together with the suburbs and exurbs located in the canton of Vaud and in the French departments of Ain and Haute-Savoie the cross-border Geneva metropolitan area as officially defined by Eurostat, w ...
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Sprocket
A sprocket, sprocket-wheel or chainwheel is a profiled wheel with teeth that mesh with a chain, track or other perforated or indented material. The name 'sprocket' applies generally to any wheel upon which radial projections engage a chain passing over it. It is distinguished from a gear in that sprockets are never meshed together directly, and differs from a pulley in that sprockets have teeth and pulleys are smooth except for timing pulleys used with toothed belts. Sprockets are used in bicycles, motorcycles, tracked vehicles, and other machinery either to transmit rotary motion between two shafts where gears are unsuitable or to impart linear motion to a track, tape etc. Perhaps the most common form of sprocket may be found in the bicycle, in which the pedal shaft carries a large sprocket-wheel, which drives a chain, which, in turn, drives a small sprocket on the axle of the rear wheel. Early automobiles were also largely driven by sprocket and chain mechanism, a practice la ...
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Fast Motion
Time-lapse photography is a technique in which the frequency at which film frames are captured (the frame rate) is much lower than the frequency used to view the sequence. When played at normal speed, time appears to be moving faster and thus ''lapsing''. For example, an image of a scene may be captured at 1 frame per second but then played back at 30 frames per second; the result is an apparent ''30 times'' speed increase. Similarly, film can also be played at a much lower rate than at which it was captured, which slows down an otherwise fast action, as in slow motion or high-speed photography. Processes that would normally appear subtle and slow to the human eye, such as the motion of the sun and stars in the sky or the growth of a plant, become very pronounced. Time-lapse is the extreme version of the cinematography technique of ''undercranking''. Stop motion animation is a comparable technique; a subject that does not actually move, such as a puppet, can repeatedly be move ...
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Dwell Mechanism
A dwell mechanism (either a linkage or cam-follower type) is an intermittent motion mechanism that alternates forward and return motion with holding position(s). Dwells in cam mechanisms Single dwell cam mechanisms A single dwell cam mechanism has a motion function which follows a dwell-rise-fall sequence that repeats. It is sometimes desired to use a rise function such that the acceleration of the follower is non-zero at its end of the rise. To maintain continuity, the fall function often begins such that the follower has the same non-zero acceleration as it had at the end of the rise function. The follower then stays stationary during the dwell function, with its velocity, acceleration, and jerk zero. There are a number of functions that can provide these motion requirements. A double-harmonic function is a common example used for single dwell. Double dwell cam mechanisms A double dwell cam mechanism has a motion function which follows a rise-dwell-fall-dwell motion fu ...
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American Standards Association
The American National Standards Institute (ANSI ) is a private non-profit organization that oversees the development of voluntary consensus standards Standardization or standardisation is the process of implementing and developing technical standards based on the consensus of different parties that include firms, users, interest groups, standards organizations and governments. Standardization ... for products, services, processes, systems, and personnel in the United States. The organization also coordinates U.S. standards with international standards so that American products can be used worldwide. ANSI accredits standards that are developed by representatives of other standards organizations, government agency, government agencies, consumer organization, consumer groups, companies, and others. These standards ensure that the characteristics and performance of products are consistent, that people use the same definitions and terms, and that products are tested the same ...
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Film Gate
The film gate is the rectangular opening in the front of a motion picture camera where the film is exposed to light. The film gate can be seen by removing the lens and rotating the shutter out of the way. The film is held on a uniform plane at a calibrated distance in the gate by a pressure plate behind the film. Occasionally, as the film passes through the gate, friction can cause small slivers of celluloid to break off and stick in the side of the opening. These pieces of debris are called ''hairs''. A "hair in the gate" will remain in front of the film and create a dark line that sticks into the edge of the film frame as the camera is filming a shot. A hair can ruin the shot and is almost impossible to fix in post production without using modern digital removal techniques. Because of the intractability of this problem the focus puller (or 1st Assistant Camera) will open the camera and examine the gate for hairs at the end of each shot. Normally the assistant director will call ...
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Film Frame
In filmmaking, video production, animation, and related fields, a frame is one of the many ''still images'' which compose the complete ''moving picture''. The term is derived from the historical development of film stock, in which the sequentially recorded single images look like a framed picture when examined individually. The term may also be used more generally as a noun or verb to refer to the edges of the image as seen in a camera viewfinder or projected on a screen. Thus, the camera operator can be said to keep a car in frame by panning with it as it speeds past. Overview When the moving picture is displayed, each frame is flashed on a screen for a short time (nowadays, usually 1/24, 1/25 or 1/30 of a second) and then immediately replaced by the next one. Persistence of vision blends the frames together, producing the illusion of a moving image. The frame is also sometimes used as a unit of time, so that a momentary event might be said to last six frames, the actual dur ...
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Film Negative
In photography, a negative is an image, usually on a strip or sheet of transparent plastic film, in which the lightest areas of the photographed subject appear darkest and the darkest areas appear lightest. This reversed order occurs because the extremely light-sensitive chemicals a camera film must use to capture an image quickly enough for ordinary picture-taking are darkened, rather than bleached, by exposure to light and subsequent photographic processing. In the case of color negatives, the colors are also reversed into their respective complementary colors. Typical color negatives have an overall dull orange tint due to an automatic color-masking feature that ultimately results in improved color reproduction. Negatives are normally used to make positive prints on photographic paper by projecting the negative onto the paper with a photographic enlarger or making a contact print. The paper is also darkened in proportion to its exposure to light, so a second reversal result ...
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Maltese Cross
The Maltese cross is a cross symbol, consisting of four " V" or arrowhead shaped concave quadrilaterals converging at a central vertex at right angles, two tips pointing outward symmetrically. It is a heraldic cross variant which developed from earlier forms of eight-pointed crosses in the 16th century. Although chiefly associated with the Knights Hospitaller (Order of St. John, now the Sovereign Military Order of Malta), and by extension with the island of Malta, it has come to be used by a wide array of entities since the early modern period, notably the Order of Saint Stephen, the city of Amalfi, the Polish Order of the White Eagle (1709), the Prussian order ''Pour le Mérite'' (1740), and the Bavarian Military Merit Order (1866). Unicode defines a character named "Maltese cross" in the Dingbats range at code point U+2720 (✠); however most computer fonts render the code point as a cross pattée. History The Knights Hospitaller during the Crusades used a plain L ...
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Geneva Drive
The Geneva drive or Maltese cross is a gear mechanism that translates a continuous rotation movement into intermittent rotary motion. The ''rotating drive'' wheel is usually equipped with a pin that reaches into a slot located in the other wheel (''driven wheel'' that advances it by one step at a time. The drive wheel also has an elevated circular blocking disc that "locks" the rotating driven wheel in position between steps. History The name, Geneva drive, is derived from the devices earliest application in mechanical watches, which were popularized in Geneva, being the classical origin of watchmaking industry. The mechanism is frequently used in mechanical watches, since it can be made small and is able to withstand substantial mechanical stress. The ''Geneva drive'' is also called a "Maltese cross mechanism" due to the visual resemblance when the rotating wheel has four spokes. In the most common arrangement of the Geneva drive, the client wheel has four slots and thu ...
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Registration Pin
{{unreferenced, date=January 2014 A registration pin is a device intended to hold a piece of film, paper or other material in place during photographic exposure, copying or drawing. Registration pins are used in offset printing and cartography, to accurately position the different films or plates for multi-color work. In traditional, hand-drawn animation, the registration pins are often called pegs, and are attached to peg bar Also, in traditional, hand-taped printed circuit board artwork, usually at two or four times actual size. Sometimes on a single transparent base, usually mylar, with Layer 1 being on the front and Layer 2 being on the back, in red and green, respectively, for later "separation" into component parts using a process camera. Motion picture cameras and related applications In motion picture cameras, the pin(s) hold the film immovable during exposure. In certain "professional" motion picture cameras and "step" printers, there may be ''two'' registration pins: o ...
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Moviecam Schematic Animation
Moviecam is a motion picture equipment company specializing in movie camera systems for 35 mm film. History Originally started in Vienna, Austria as an in-house project of Fritz Gabriel Bauer and Walter Kindler's Moviegroup film production company in the late 1960s, the amount of research and development needed to create a new and modern motion picture camera system from scratch led to the formal creation of Moviecam as an independent corporate entity in 1976. Although only three camera models (SuperAmerica, Compact, and SL) were produced in significant quantities for international usage, the high quality camera design, simplicity of usage compared to the contemporary models of Arri and Panavision, and integration of modern and pioneering camera features led to widespread usage in the film industry. Arri subsequently bought the company in the 1990s. At Arri, Bauer developed, together with Walter Trauninger and their camera development team, the Arricam System, which combined ...
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