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.

Projecteur cinématographique 35mm
35 mm movie projector in operation.

History

CinematographeProjection
The cinématographe Lumière in projection mode.
Zoopraxiscope 16485d
Simulation of a spinning zoopraxiscope
Dom kulture u Trsteniku 2
An early projector and seats from a movie theater

The first movie projector was the Zoopraxiscope, invented by British photographer Eadweard Muybridge in 1879. The zoopraxiscope projected images from rotating glass disks in rapid succession to give the impression of motion. The stop-motion 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.[1]

Kazimierz Prószyński (4 April 1875 – 13 March 1945), born in Warsaw, Poland, was a Polish inventor active in the field of cinema. He patented his first film camera, called Pleograph (in Polish spelling: Pleograf), before the Lumière brothers, and later went on to improve the cinema projector for the Gaumont company, as well as invent the widely used hand-held Aeroscope camera.

A more sophisticated movie projector was invented by Frenchman Louis Le Prince while working in Leeds. In 1888 Le Prince took out a 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 first ever motion picture, the Roundhay Garden Scene. The pictures were privately exhibited in Hunslet.

The Lumière brothers invented the first successful movie projector. They made their first film, Sortie de l'usine Lumière de Lyon, in 1894, which was publicly screened at L'Eden, La Ciotat a year later. The first commercial, public screening of cinematographic films happened in Paris on 28 December 1895.[2] The cinematograph was also exhibited at the Paris Exhibition of 1900. At the Exhibition, films made by the Lumière Brothers were projected onto a large screen measuring 16 by 21 meters (approximately 52.5 x 69 feet).[3]

Decline of film projectors

In 1999,[4] digital cinema projectors were being tried out in some movie theatres. These early projectors played the movie stored on a computer, and sent to the projector electronically. Due to their relatively low resolution (usually only 2K) 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 theatres started replacing film projectors with digital projectors. In 2013, it was estimated that 92% of movie theatres in the United States had converted to digital, with 8% still playing film. In 2015, 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 35mm film production would continue for several years.[5]

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 so equipped.

Physiology

In 1912 Max Wertheimer discovered beta movement and the phi phenomenon. In each the brain constitutes an experience of apparent movement when presented with a sequence of near-identical still images. This theory is said to account for the illusion of motion which results when a series of film images is displayed in quick succession, rather than the perception of the individual frames in the series.

Persistence of vision should be compared with the related phenomena of beta movement and phi movement. A critical part of understanding these visual perception phenomena 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. Generally, the frame rate of 16 frames per second (frame/s) 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 ones eyes at a certain rate. If done fast enough, the viewer will be able to randomly "trap" the image between frames, or during shutter motion. This will not work with (now obsolete) 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 film projectors.

Silent films usually were not projected at constant speeds, but rather were varied throughout the show at the discretion of the projectionist, often with some notes provided by the distributor. This was more a function of hand-cranked projectors than the silence. 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 up - sometimes even faster than modern sound film speed (24 frame/s).

16 frame/s - though sometimes used as a camera shooting speed - was inadvisable for projection, due to the high risk of the nitrate-base prints catching fire in the projector. (A dramatic rendition of a nitrate print fire and its potentially devastating effects is famously found in Nuovo Cinema Paradiso, which revolves around the goings-on of a projectionist.) Nitrate film stock was replaced by cellulose triacetate in 1948.

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 (e.g. Showscan and Maxivision) which project at higher rates—60 frames/sec for Showscan and 48 for Maxivision. The Hobbit was shot at 48 frames/sec 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.[6]

Principles of operation

Projmech
35 mm Kinoton FP30ST movie projector, with parts labeled. (Click thumbnail for larger text.)

Projection elements

As in a slide projector there are essential optical elements:

Light source

Incandescent lighting and even limelight were the first light sources used in film projection. In the early 1900s up until the late 1960s, carbon arc lamps were the source of light in almost all theaters in the world.

The Xenon arc lamp was introduced in Germany in 1957 and in the US in 1963. After film platters became commonplace in the 1970s, Xenon lamps became the most common light source, as they could stay lit for extended periods of time, whereas a carbon rod used for a carbon arc could last for an hour at the most.

Most lamp houses in a professional theatrical setting produce sufficient heat to burn the film should the film remain stationary for more than a fraction of a second. Because of this,absolute care must be taken in inspecting a film so that it should not break in the gate and be damaged, particularly if it is flammable cellulose nitrate film stock.

Reflector and condenser lens

A curved reflector redirects light that would otherwise be wasted toward the condensing lens.

A positive curvature lens concentrates the reflected and direct light toward the film gate.

Douser

(Also spelled dowser.)

A metal or asbestos blade which cuts off light before it can get to the film. The douser is usually part of the lamphouse, and may be manually or automatically operated. Some projectors have a second, electrically controlled douser that is used for changeovers (sometimes called a "changeover douser" or "changeover shutter"). Some projectors have a third, mechanically controlled douser that automatically closes when the projector slows down (called a "fire shutter" or "fire douser"), to protect the film if the projector stops while the first douser is still open. Dousers protect the film when the lamp is on but the film is not moving, preventing the film from melting from prolonged exposure to the direct heat of the lamp. It also prevents the lens from scarring or cracking from excessive heat.

Film gate and frame advance

If a roll of film were merely passed between the light source and the lens of the projector, all that would be visible on screen would be a continuous blurred series of images sliding from one edge to the other. In order to see a clear picture, the moving film must be stopped and held still briefly while the shutter opens and closes. The gate is where the film is held still prior to the opening of the shutter. This is the case for both filming and projecting movies. A single image of the series of images comprising the movie is positioned and held flat within the gate. The gate also provides a slight amount of friction so that the film does not advance or retreat except when driven to advance the film to the next image. The intermittent mechanism advances the film within the gate to the next frame while the shutter is closed. Registration pins prevent the film from advancing while the shutter is open. In most cases the registration of the frame can be manually adjusted by the projectionist, and more sophisticated projectors can maintain registration automatically.

Shutter

It is the gate and shutter that gives the illusion of one full frame being replaced exactly on top of another full frame. The gate holds the film still while the shutter is open. A rotating petal or gated cylindrical shutter interrupts the emitted light during the time the film is advanced to the next frame. The viewer does not see the transition, thus tricking the brain into believing a moving image is on screen. Modern shutters are designed with a flicker-rate of two times (48 Hz) or even sometimes three times (72 Hz) the frame rate of the film, so as to reduce the perception of screen flickering. (See Frame rate and Flicker fusion threshold.) Higher rate shutters are less light efficient, requiring more powerful light sources for the same light on screen.

Movie projection 4 stages en
Mechanical sequence when image is shown twice and then advanced.
Outer sprockets rotate continuously while the frame advance sprockets are controlled by the mechanism shown - a Geneva drive.

Imaging lens and aperture plate

AskaniaDiastar 400mm side
Imaging lens Diastar of an Askania 35mm movie projector (focal length: 400 mm)

A projection objective with multiple optical elements directs the image of the film to a viewing screen. Projector lenses differ in aperture and focal length to suit different needs. Different lenses are used for different aspect ratios.

One way that aspect ratios are set is with the appropriate aperture plate, a piece of metal with a precisely cut rectangular hole in the middle of equivalent aspect ratio. The aperture plate is placed just behind the gate, and masks off any light from hitting the image outside of the area intended to be shown. All films, even those in the standard Academy ratio, have extra image on the frame that is meant to be masked off in the projection.

Using an aperture plate to accomplish a wider aspect ratio is inherently wasteful of film, as a portion of the standard frame is unused. One solution that presents itself at certain aspect ratios is the "2-perf" pulldown, where the film is advanced less than one full frame in order to reduce the unexposed area between frames. This method requires a special intermittent mechanism in all film handling equipment throughout the production process, from the camera to the projector. This is costly, and prohibitively so for some theaters. The anamorphic format uses special optics to squeeze a high aspect ratio image onto a standard Academy frame thus eliminating the need to change the costly precision moving parts of the intermittent mechanisms. A special anamorphic lens is used on the camera to compress the image, and a corresponding lens on the projector to expand the image back to the intended aspect ratio.

Viewing screen

In most cases this is a reflective surface which may be either aluminized (for high contrast in moderate ambient light) or a white surface with small glass beads (for high brilliance under dark conditions). A switchable projection screen can be switched between opaque and clear by a safe voltage under 36V AC and is viewable from both sides. In a commercial theater, the screen also has millions of very small, evenly spaced holes in order to allow the passage of sound from the speakers and subwoofer which often are directly behind it.

Film transport elements

Film supply and takeup

In the two-reel system the projector has two reels–one is the feed reel, which holds the part of the film that has not been shown, the other is the takeup reel, which winds the film that has been shown. In a two-reel projector the feed reel has a slight drag to maintain tension on the film, while the takeup reel is constantly driven with a mechanism that has mechanical 'slip,' to allow the film to be wound under constant tension so the film is wound in a smooth manner.

The film being wound on the takeup reel is being wound "head in, tails out." This means that the beginning (or "head") of the reel is in the center, where it is inaccessible. As each reel is taken off of the projector, it must be re-wound onto another empty reel. In a theater setting there is often a separate machine for rewinding reels. For the 16 mm projectors that were often used in schools and churches, the projector could be re-configured to rewind films.

The size of the reels can vary based on the projectors, but generally films are divided and distributed in reels of up to 2,000 feet (610 metres), about 22 minutes at 24 frames/sec). Some projectors can even accommodate up to 6,000 feet (1,800 metres), which minimizes the number of changeovers (see below) in a showing. Certain countries also divide their film reels up differently; Russian films, for example, often come on 1,000-foot (300 m) reels, although it's likely that most projectionists working with changeovers would combine them into longer reels of at least 2,000 feet (610 metres), to minimize changeovers and also give sufficient time for threading and any possibly needed troubleshooting time.

Films are identified as "short subjects," taking one reel or less of film, "two-reelers," requiring two reels of film (such as some of the early Laurel & Hardy, 3 Stooges, and other comedies), and "features," which can take any number of reels (although most are limited to 1½ to 2 hours in length, enabling the theater to have multiple showings throughout the day and evening, each showing with a feature, commercials, and intermission to allow the audiences to change). In the "old days" (i.e., ca. 1930–1960), "going to the movies" meant seeing a short subject (a newsreel, short documentary, a "2-reeler," etc.), a cartoon, and the feature. Some theaters would have movie-based commercials for local businesses, and the state of New Jersey required showing a diagram of the theater showing all of the exits.

Because a single film reel does not contain enough film to show an entire feature, the film is distributed on multiple reels. To prevent having to interrupt the show when one reel ends and the next is mounted, two projectors are used in what is known as a "changeover system," after the switching mechanism that operates between the end of one reel on the first projector and the beginning of the next reel on the second projector. The two-reel system was used almost universally for movie theaters before the advent of the single-reel system in order to be able to show feature-length films. Although one-reel long-play systems tend to be more popular with the newer multiplexes, the two-reel system is still in significant use to this day.

The projector operator operates two projectors, starting the first reel of the show on projector "A." While this reel is being shown, the projectionist threads the second reel on projector "B."

As the reel being shown approaches its end, the projectionist looks for cue marks at the upper-right corner of the picture. Usually these are dots or circles, although they can also be slashes. Some older films occasionally used squares or triangles, and sometimes positioned the cues in the middle of the right edge of the picture.

The first cue appears twelve feet (3.7 metres) before the end of the program on the reel, equivalent to eight seconds at 24 frames/sec. This cue signals the projectionist to start the motor of the projector containing the next reel. After another ten and a half feet (3.2 m) of film is shown (seven seconds at 24 frames/sec), the changeover cue should appear, which signals the projectionist to actually make the changeover. When this second cue appears, the projectionist has one and a half feet (460 mm), or one second at 24 frame/s, to make the changeover. If it doesn't occur within one second, the tail leader of the reel coming to an end will be projected on the screen.

Twelve feet before the "first frame of action," Academy leaders have a "START" frame. The projectionist positions the "START" in the gate of the projector. When the first cue is seen, the motor of the starting projector is started. Seven seconds later the end of the leader and start of program material on the new reel should just reach the gate of the projector when the changeover cue is seen.

On some projectors, the operator would be alerted to the time for a change by a bell that operated when the feed reel rotation exceeded a certain speed (the feed reel rotates faster as the film is exhausted), or based on the diameter of the remaining film (Premier Changeover Indicator Pat. No. 411992), although many projectors do not have such an auditory system.

During the initial operation of a changeover, the two projectors use an interconnected electrical control connected to the changeover button so that as soon as the button is pressed, the changeover douser on the outgoing projector is closed in sync with the changeover douser on the incoming projector opening. If done properly, a changeover should be virtually unnoticeable to an audience. In older theaters, there may be manually operated, sliding covers in front of the projection booth's windows. A changeover with this system is often clearly visible as a wipe on the screen.

Once the changeover has been made, the projectionist unloads the full takeup reel from projector "A," moves the now-empty reel (that used to hold the film just unloaded) from the feed spindle to the takeup spindle, and loads reel #3 of the presentation on projector "A." When reel 2 on projector "B" is finished, the changeover switches the live show from projector "B" back to projector "A," and so on for the rest of the show.

When the projectionist removes a finished reel from the projector it is "tails out," and needs to be rewound before the next show. The projectionist usually uses a separate rewind machine and a spare empty reel, and rewinds the film so it is "head out," ready to project again for the next show.

One advantage of this system (at least for the theatre management) was that if a programme was running a few minutes late for any reason, the projectionist would simply omit one (or more) reels of film to recover the time.

Projector and platter
Christie AW3 platter, BIG SKY Industries console, and Century SA projector.

There are two largely used single-reel systems (also known as long-play systems) today: the tower system (vertical feed and takeup) and the platter system (non-rewinding; horizontal feed and takeup).

The tower system largely resembles the two-reel system, except in that the tower itself is generally a separate piece of equipment used with a slightly modified standard projector. The feed and takeup reels are held vertically on the axis, except behind the projector, on oversized spools with 12,000-foot (3,700 m) capacity or about 133 minutes at 24 frame/s. This large capacity alleviates the need for a changeover on an average-length feature; all of the reels are spliced together into one giant one. The tower is designed with four spools, two on each side, each with its own motor. This allows the whole spool to be immediately rewound after a showing; the extra two spools on the other side allow for a film to be shown while another is being rewound or even made up directly onto the tower. Each spool requires its own motor in order to set proper tensioning for the film, since it has to travel (relatively) much further between the projector film transport and the spools. As each spool gains or loses film, the tension must be periodically checked and adjusted so that the film can be transported on and off the spools without either sagging or snapping.

In a platter system the individual 20-minute reels of film are also spliced together as one large reel, but the film is then wound onto a horizontal rotating table called a platter. Three or more platters are stacked together to create a platter system. Most of the platters in a platter system will be occupied by film prints; whichever platter happens to be empty serves as the "take-up reel" to receive the film that is playing from another platter.

The way the film is fed from the platter to the projector is not unlike an eight-track audio cartridge. Film is unwound from the center of the platter through a mechanism called a payout unit which controls the speed of the platter's rotation so that it matches the speed of the film as it is fed to the projector. The film winds through a series of rollers from the platter stack to the projector, through the projector, through another series of rollers back to the platter stack, and then onto the platter serving as the take-up reel.

This system makes it possible to project a film multiple times without needing to rewind it. As the projectionist threads the projector for each showing, the payout unit is transferred from the empty platter to the full platter and the film then plays back onto the platter it came from. In the case of a double feature, each film plays from a full platter onto an empty platter, swapping positions on the platter stack throughout the day.

Nonrewind
nonrewind in Royal - Malmö, Sweden.

The advantage of a platter is that the film need not be rewound after each show, which can save labor. Rewinding risks rubbing the film against itself, which can cause scratching of the film and smearing of the emulsion which carries the pictures. The disadvantages of the platter system are that the film can acquire diagonal scratches on it if proper care is not taken while threading film from platter to projector, and the film has more opportunity to collect dust and dirt as long lengths of film are exposed to the air. A clean projection booth kept at the proper humidity is of great importance, as are cleaning devices that can remove dirt from the film print as it plays.

The single reel system can allow for the complete automation of the projection booth operations, given the proper auxiliary equipment. Since films are still transported in multiple reels they must be joined together when placed on the projector reel and taken apart when the film is to be returned to the distributor. It is the complete automation of projection that has enabled the modern "multiplex" cinema - a single site typically containing from 8 to 24 theaters with only a few projection and sound technicians, rather than a platoon of projectionists. The multiplex also offers a great amount of flexibility to a theater operator, enabling theaters to exhibit the same popular production in more than one auditorium with staggered starting times. It is also possible, with the proper equipment installed, to "interlock", i.e. thread a single length of film through multiple projectors. This is very useful when dealing with the mass crowds that an extremely popular film may generate in the first few days of showing, as it allows for a single print to serve more patrons.

Feed and extraction sprockets

Smooth wheels with triangular pins called sprockets engage perforations punched into one or both edges of the film stock. These serve to set the pace of film movement through the projector and any associated sound playback system.

Film loop

As with motion picture cameras, the intermittent motion of the gate requires that there be loops above and below the gate in order to serve as a buffer between the constant speed enforced by the sprockets above and below the gate and the intermittent motion enforced at the gate. Some projectors also have a sensitive trip pin above the gate to guard against the upper loop becoming too big. If the loop hits the pin, it will close the dousers and stop the motor to prevent an excessively large loop from jamming the projector.

Film gate pressure plate

A spring-loaded pressure plate functions to align the film in a consistent image plane, both flat and perpendicular to the optical axis. It also provides sufficient drag to prevent film motion during the frame display, while still allowing free motion under control of the intermittent mechanism. The plate also has spring-loaded runners to help hold film while in place and advance it during motion.

Intermittent mechanism

The intermittent mechanism can be constructed in different ways. For smaller gauge projectors (8 mm and 16 mm), a pawl mechanism engages the film's sprocket hole one side, or holes on each side. This pawl advances only when the film is to be moved to the next image. As the pawl retreats for the next cycle it is drawn back and does not engage the film. This is similar to the claw mechanism in a motion picture camera.

In 35 mm and 70 mm projectors, there usually is a special sprocket immediately underneath the pressure plate, known as the intermittent sprocket. Unlike all the other sprockets in the projector, which run continuously, the intermittent sprocket operates in tandem with the shutter, and only moves while the shutter is blocking the lamp, so that the motion of the film cannot be seen. It also moves in a discrete amount at a time, equal to the number of perforations that make up a frame (4 for 35 mm, 5 for 70 mm). The intermittent movement in these projectors is usually provided by a Geneva drive, also known as the Maltese Cross mechanism.

IMAX projectors use what is known as the rolling loop method, in which each frame is sucked into the gate by a vacuum, and positioned by registration pins in the perforations corresponding to that frame.

Types

Projectors are classified by the size of the film used, i.e. the film format. Typical film sizes:

8 mm

Long used for home movies before the video camera, this uses double sprocketed 16 mm film, which is run through the camera, exposing one side, then removed from the camera, the takeup and feed reels are switched, and the film run through a second time, exposing the other side. The 16 mm film is then split lengthwise into two 8 mm pieces that are spliced to make a single projectable film with sprockets holes on one side.

Super 8

Developed by Kodak, this film stock uses very small sprocket holes close to the edge that allow more of the film stock to be used for the images. This increases the quality of the image. The unexposed film is supplied in the 8 mm width, not split during processing as is the earlier 8 mm. Magnetic stripes could be added to carry encoded sound to be added after film development. Film could also be pre-striped for direct sound recording in suitably equipped cameras for later projection.

9.5 mm

Film format introduced by Pathé Frères in 1922 as part of the Pathé Baby amateur film system. It was conceived initially as an inexpensive format to provide copies of commercially made films to home users. The format uses a single, central perforation (sprocket hole) between each pair of frames, as opposed to 8 mm film which has perforations along one edge, and most other film formats which have perforations on each side of the image. It became very popular in Europe over the next few decades and is still used by a small number of enthusiasts today. Over 300,000 projectors were produced and sold mainly in France and England, and many commercial features were available in the format. In the sixties the last projectors of this format were being produced. The gauge is still alive today. 16mm projectors are converted to 9,5mm and it is still possible to buy film stock (from the French Color City company).

16 mm

This was a popular format for audio-visual use in schools and as a high-end home entertainment system before the advent of broadcast television. In broadcast television news, 16mm film was used before the advent of electronic news-gathering. The most popular home content were comedic shorts (typically less than 20 minutes in length in the original release) and bundles of cartoons previously seen in movie theaters. 16 mm enjoys widespread use today as a format for short films, independent features and music videos, being a relatively economical alternative to 35mm. 16mm film was a popular format used for the production of TV shows well into the HDTV era.

35 mm

The most common film size for theatrical productions during the 20th century. In fact, the common 35 mm camera, developed by Leica, was designed to use this film stock and was originally intended to be used for test shots by movie directors and cinematographers.

VistaVision 8 perf 35 mm film
A diagram of the VistaVision format

35 mm film is typically run vertically through the camera and projector. In the mid-1950s the VistaVision[7] system presented wide screen movies in which the film moved horizontally, allowing much more film to be used for the image as this avoided the anamorphic reduction of the image to fit the frame width. As this required specific projectors it was largely unsuccessful as a presentation method while remaining attractive as filming, intermediate, and source for production printing and as an intermediate step in special effects to avoid film granularity, although the latter is now supplanted by digital methods.

70 mm

35mm film audio macro
A photo of a 35 mm film print featuring all four audio formats (or "quad track")- from left to right: SDDS (blue area to the left of the sprocket holes), Dolby Digital (grey area between the sprocket holes labelled with the Dolby "Double-D" logo in the middle), analog optical sound (the two white lines to the right of the sprocket holes), and the DTS time code (the dashed line to the far right.)

High-end movie productions were often produced in this film gauge in the 1950s and 1960s and many very large screen theaters are still capable of projecting it in the 21st century. It is often referred to as 65/70, as the camera uses film 65 mm wide, but the projection prints are 70 mm wide. The extra five millimeters of film accommodated the soundtrack, usually a six track magnetic stripe. The most common theater installation would use dual gauge 35/70mm projectors.

70 mm film is also used in both the flat and domed IMAX projection system. In IMAX the film is transported horizontally in the film gate, similar to VistaVision. Some productions intended for 35 mm anamorphic release were also released using 70 mm film stock. A 70 mm print made from a 35 mm negative is significantly better in appearance than an all-35 mm process, and allowed for a release with 6 track magnetic audio.

The advent of 35 mm prints with digital soundtracks in the 1990s largely supplanted the widespread release of the more expensive 70 mm prints.

Sound

Regardless of the sound format, any sound represented on the film image itself will not be the sound for the particular frame it occupies. In the gate of the projector head, there is no space for a reader, and the film is not travelling smoothly at the gate position. Consequently, all optical sound formats must be offset from the image because the sound reader is usually located above (for magnetic readers and most digital optical readers) or below (for analog optical readers and a few digital optical) the projector head.

See the 35 mm film article for more information on both digital and analog methods.

Analog optical sound

Optical sound constitutes the recording and reading of amplitude based on the amount of light that is projected through a soundtrack area on a film using an illuminating light or laser and a photocell or photodiode. As the photocell picks up the light in varying intensities, the electricity produced is intensified by an amplifier, which in turn powers a loudspeaker, where the electrical impulses are turned into air vibrations and thus, sound waves. In 16 mm, this optical soundtrack is a single mono track placed on the right side of the projected image, and the sound head is 26 frames after the gate. In 35 mm, this can be mono or stereo, on the left side of the projected image, with the sound head 21 frames after the gate.[8]

The first form of optical sound was represented by horizontal bands of clear (white) and solid (black) area. The space between solid points represented amplitude and was picked up by the photo-electric cell on the other side of a steady, thin beam of light being shined through it. This variable density form of sound was eventually phased out because of its incompatibility with color stocks. The alternative and ultimately the successor of variable density has been the variable area track, in which a clear, vertical waveform against black represents the sound, and the width of the waveform is equivalent to the amplitude. Variable area does have slightly less frequency response than variable density, but because of the grain and variable infrared absorption of various film stocks, variable density has a lower signal-to-noise ratio.

Optical stereo is recorded and read through a bilateral variable area track. Dolby MP matrix encoding is used to add extra channels beyond the stereo pair. Left, center, right and surround channels are matrix-encoded into the two optical tracks, and decoded using licensed equipment.

In the 1970s and early 1980s, optical sound Super-8 mm copies were produced mainly for airline in-flight movies. Even though this technology was soon made obsolete by video equipment, the majority of small-gauge films used magnetic sound rather than optical sound for a higher frequency range.

Magnetic sound

Magnetic sound is no longer used in commercial cinema, but between 1952 and the early 1990s (when optical digital movie sound rendered it obsolete) it provided the highest fidelity sound from film because of its wider frequency range and superior signal to noise ratio compared to optical sound. There are two forms of magnetic sound in conjunction with projection: double-head and striped.

The first form of magnetic sound was the double-head system, in which the movie projector was interlocked with a dubber playing a 35 mm reel of a full-coat, or film completely coated with magnetic iron-oxide. This was introduced in 1952 with Cinerama, holding six tracks of stereophonic sound. Stereophonic releases throughout 1953 also used an interlocked full-coat for three-channel stereophonic sound.

In interlock, since the sound is on a separate reel, it does not need to be offset from the image. Today, this system is usually used only for very low-budget or student productions, or for screening rough cuts of films before the creation of a final married print. Sync between the two reels is checked with SMPTE leader, also known as countdown leader. If the two reels are synced, there should be one frame of "beep" sound exactly on the "2" frame of the countdown - 2 seconds or 48 frames before the picture start.

Striped magnetic film is motion picture film in which 'stripes' of magnetic oxide are placed on the film between the sprocket holes and the edge of the film, and sometimes also between the sprocket holes and the image. Each of these stripes has one channel of the audio recorded on it. This technique was first introduced in September, 1953 by Hazard E. Reeves for Cinemascope. Four tracks are present on the film: Left, Center, Right and Surround. This 35mm four-track magnetic sound format was used from 1954 through 1982 for "roadshow" screenings of big-budget feature films.

70 mm, which had no optical sound, used the 5 millimeters gained between the 65 mm negative and the final release print to place three magnetic tracks outside of the perforations on each side of the film for a total of six tracks. Until the introduction of digital sound, it was fairly common for 35 mm films to be blown up to 70 mm often just to take advantage of the greater number of sound tracks and the fidelity of the audio.

Although magnetic audio was of excellent quality it also had significant disadvantages. Magnetic sound prints were expensive, 35mm magnetic prints cost roughly twice as much as optical sound prints, whilst 70mm prints could cost up to 15 times as much as 35mm prints. Furthermore, the oxide layer wore out faster than the film itself, and magnetic tracks were prone to damage and accidental erasure. Because of the high cost of installing magnetic sound reproduction equipment only a minority of movie theaters ever installed it and the magnetic soundheads needed considerable maintenance to keep their performance up to standard. As a consequence the use of the Cinemascope 35mm four-track magnetic sound format decreased significantly during the course of the 1960s and received stiff competition from the Dolby SVA optical encoding format. However, 70mm film continued to be used for prestigious "roadshow" screenings until the introduction of digital sound on 35mm film in the early 1990s removed one of the major justifications for using this expensive format.

On certain stocks of Super 8 and 16 mm an iron-oxide sound recording strip was added for the direct synchronous recording of sound which could then be played by projectors with a magnetic sound head. It has since been discontinued by Kodak on both gauges.

Digital

Modern theatrical systems use optical representations of digitally encoded multi-channel sound. An advantage of digital systems is that the offset between the sound and picture heads can be varied and then set with the digital processors. Digital sound heads are usually above the gate. All digital sound systems currently in use have the ability to instantly and gracefully fall back to the analog optical sound system should the digital data be corrupt or the whole system fail.

Cinema Digital Sound (CDS)

Created by Kodak and ORC (Optical Radiation Corporation), Cinema Digital Sound was the first attempt to bring multi-channel digital sound to first-run theaters. CDS was available on both 35 mm and 70 mm films. Film prints equipped with CDS did not have the conventional analog optical or magnetic soundtracks to serve as a back-up in case the digital sound was unreadable. Another disadvantage of not having an analog back-up track is that CDS required extra film prints be made for the theaters equipped to play CDS. The three formats that followed, Dolby Digital, DTS and SDDS, can co-exist with each other and the analog optical soundtrack on a single version of the film print. This means that a film print carrying all three of these formats (and the analog optical format, usually Dolby SR) can be played in whichever format the theater is equipped to handle. CDS did not achieve widespread use and ultimately failed. It premiered with the film Dick Tracy and was used with several other films, such as Days of Thunder and Terminator 2: Judgement Day.

Sony Dynamic Digital Sound (SDDS)

SDDS runs on the outside of 35 mm film, between the perforations and the edges, on both edges of the film. It was the first digital system that could handle up to eight channels of sound. The additional two tracks are for an extra pair of screen channels (Left Center and Right Center) located between the 3 regular screen channels (Left, Center and Right). A pair of CCDs located in a unit above the projector reads the two SDDS tracks. The information is decoded and decompressed before being passed along to the cinema sound processor. By default, SDDS units use an onboard Sony Cinema Sound Processor, and when the system is set up in this manner, the theatre's entire sound system can be equalized in the digital domain. The audio data in an SDDS track is compressed in the 20-bit ATRAC2 compression scheme at a ratio of about 4.5:1. SDDS premiered with the film Last Action Hero. SDDS was the least commercially successful of the three competing digital sound systems for 35mm film. Sony ceased the sale of SDDS processors in 2001-2002.

Dolby Digital

Dolby Digital data is printed in the spaces between the perforations on the soundtrack side of the film, 26 frames before the picture. Release prints with Dolby Digital always include an analog Dolby Stereo soundtrack with Dolby SR noise reduction, thus these prints are known as Dolby SR-D prints. Dolby Digital produces 6 discrete channels. In a variant called SR-D EX, the left and right surround channels can be dematrixed into left, right, and back surround, using a matrix system similar to Dolby Pro Logic. The audio data in a Dolby Digital track is compressed in the 16-bit AC-3 compression scheme at a ratio of about 12:1. The images between each perforation are read by a CCD located either above the projector or in the regular analog sound head below the film gate, a digital delay within the processor allowing correct lip-sync to be achieved regardless of the position of the reader relative to the picture gate. The information is then decoded, decompressed and converted to analog; this can happen either in a separate Dolby Digital processor that feeds signals to the cinema sound processor, or digital decoding can be built into the cinema processor.One disadvantage of this system is if the digital printing is not entirely within the space between the sprocket holes; if the track was off a bit on either the top or the bottom, the sound track would be unplayable, and a replacement reel would have to be ordered.

In 2006, Dolby discontinued the sale of their external SR-D processor (the DA20), but included Dolby Digital decoding in their CP500 and later CP650 cinema processors.

A consumer version of Dolby Digital is also used on most DVDs, often at higher data rates than the original film. A bit for bit version is used on Blu-ray Discs and HD DVDs called Dolby TrueHD. Dolby Digital officially premiered with the film Batman Returns, but it was earlier tested at some screenings of Star Trek VI: The Undiscovered Country.

Digital Theater Systems (DTS)

DTS actually stores the sound information on separate CD-ROMs supplied with the film. The CDs are fed into a special, modified computer which syncs up with the film through the use of DTS time code, decompresses the sound, and passes it through to a standard cinema processor. The time code is placed between the optical sound tracks and the actual picture, and is read by an optical LED ahead of the gate. The time code is actually the only sound system which is not offset within the film from the picture, but still needs to be physically set offset ahead of the gate in order to maintain continuous motion. Each disc can hold slightly over 90 minutes of sound, so longer films require a second disc. Three types of DTS sound exist: DTS-ES (Extended Surround), an 8 channel digital system; DTS-6, a 6 track digital system, and a now-obsolete 4 channel system. DTS-ES derives a back surround channel from the left surround and right surround channels using Dolby Pro Logic. The audio data in a DTS track is compressed in the 20-bit APTX-100 compression scheme at a ratio of 4:1.

Of the three digital formats currently in use, DTS is the only one that has been used with 70 mm presentations. DTS was premiered on Jurassic Park. Datasat Digital Entertainment, purchaser of DTS's cinema division in May 2008, now distributes Datasat Digital Sound to professional cinemas worldwide. A consumer version of DTS is available on some DVDs, and was used to broadcast stereo TV prior to DTV. A bit for bit version of the DTS soundtrack is on Blu-ray Discs and HD DVDs called DTS-HD MA (DTS-HD Master Audio).

Leaders

Academy leader is placed at the head of release prints containing information for the projectionist and featuring numbers which are black on a clear background, counting from 11 to 3 at 16 frame intervals (16 frames in 35 mm film = 1 ft). At -12 feet there is a START frame.

SMPTE leader is placed at the head of release prints or video masters containing information for the projectionist or video playback tech. The numbers count down in seconds from 8 to 2 at 24 frame intervals ending at the first frame of the "2" followed by 47 frames of black.

Usually there's an audio POP that play 48 frames (2 seconds at 24 frame per second) before first frame of action (FFOA) that helps to sync audio and video during printing processes or postproduction.

Types of lenses and screens

Spherical

Most motion picture lenses are of the spherical variety. Spherical lenses do not distort the image intentionally. Used alone for standard and cropped wide screen projection, and in conjunction with an anamorphic adapter for anamorphic wide screen projection, the spherical lens is the most common and versatile projection lens type.

Anamorphic

WpNonAnamorphed1.96
Simulated wide screen image with 1.96 to 1 ratio as it would be seen in a camera viewfinder or on a theater screen
WpAnamorphedTo1.33
Simulated anamorphed image with 1.33 to 1 ratio (4:3) as it would appear on a frame of film

Anamorphic filming uses only special lenses, and requires no other modifications to the camera, projector and intermediate gear. The intended wide screen image is compressed optically, using additional cylindrical elements within the lens so that when the compressed image strikes the film, it matches the standard frame size of the camera. At the projector a corresponding lens restores the wide aspect ratio to be seen on the screen. The anamorphic element can be an attachment to existing spherical lenses.

Some anamorphic formats utilized a more squarish aspect ratio (1.18:1, vs. the Academy 1.375:1 ratio) on-film in order to accommodate more magnetic and/or optical tracks. Various anamorphic implementations have been marketed under several brand names, including CinemaScope, Panavision and Superscope, with Technirama implementing a slightly different anamorphic technique using vertical expansion to the film rather than horizontal compression. Large format anamorphic processes included Ultra Panavision and MGM Camera 65 (which was renamed Ultra Panavision 70 in the early 60s). Anamorphic is sometimes called "scope" in theater projection parlance, presumably in reference to CinemaScope.

Fish eye with dome

The IMAX dome projection method (called "OMNIMAX") uses 70 mm film running sideways through the projector to maximize the image area and extreme wide angle lenses to obtain an almost hemispherical image. The field of view is tilted, as is the projection hemisphere, so one may view a portion of the ground in the foreground. Owing to the great area covered by the picture it is not as bright as seen with flat screen projection, but the immersive qualities are quite convincing. While there are not many theaters capable of displaying this format there are regular productions in the fields of nature, travel, science, and history, and productions may be viewed in most large urban regions. These dome theaters are mostly located in large and prosperous science and technology museums.

Wide and deep flat screen

The IMAX flat screen system uses large format film, a wide and deep screen, and close and quite steep "stadium" seating. The effect is to fill the visual field to a greater degree than is possible with conventional wide screen systems. Like the IMAX dome, this is found in major urban areas, but unlike the dome system it is practical to reformat existing movie releases to this method. Also, the geometry of the theater and screen are more amenable to inclusion within a newly constructed but otherwise conventional multiple theater complex than is the dome style theater.

Multiple cameras and projectors

One wide screen development during the 1950s used non-anamorphic projection, but used three side by side synchronised projectors. Called Cinerama, the images were projected onto an extremely wide, curved screen. Some seams were said to be visible between the images but the almost complete filling of the visual field made up for this. This showed some commercial success as a limited location (only in major cities) exhibition of the technology in This is Cinerama, but the only memorable story-telling film made for this technology was How the West Was Won, widely seen only in its Cinemascope re-release.

While neither a technical nor a commercial success, the business model survives as implemented by the documentary production, limited release locations, and long running exhibitions of IMAX dome movies.

Three-dimensional

For techniques used to display pictures with a three-dimensional appearance, see the 3-D film article for some movie history and the stereoscopy article for technical information.

See also

References

  1. ^ "Motion Picture Pioneer: Eadweard Muybridge and the Zoopraxiscope". Retrieved 2012-12-17.
  2. ^ Louis Lumière, The Lumière Cinematograph. In:Fielding, Raymond (1979). A technological history of motion pictures and television: an anthology from the pages of the Journal of the Society of Motion Picture and Television Engineers. University of California Press. pp. 49–51. ISBN 0-520-03981-5.
  3. ^ Cinematograph, Louis Lumière. “1936 the Lumière Cinematograph.” SMPTE Journal 105, no. 10 (October 1, 1996): 608–611.
  4. ^ McCarthy, Todd (25 June 1999). "Digital cinema is the future … or is it?". variety.com.
  5. ^ "Tarantino, Nolan, Apatow, Abrams Join Together to Save 35mm Film". firstshowing.net.
  6. ^ "DOUBLE-BLADED SHUTTER, CRITICAL FLICKER FREQUENCY/FIGURE_01_08". cinemathequefroncaise.com.
  7. ^ Nowell-Smith, Geoffrey (ed.) The Oxford History of World Cinema, pp. 446–449. Oxford University Press: Oxford, 1996.
  8. ^ Kodak Film Notes Issue # H-50-03: Projection practices and techniques - see Manuals at http://www.film-tech.com/

External links

Backscatter (photography)

In photography, backscatter (also called near-camera reflection) is an optical phenomenon resulting in typically circular artifacts on an image, due to the camera's flash being reflected from unfocused motes of dust, water droplets, or other particles in the air or water. It is especially common with modern compact and ultra-compact digital cameras.

Caused by the backscatter of light by unfocused particles, these artifacts are also sometimes called orbs, referring to a common paranormal claim. Some appear with trails, suggesting motion.

Bioscop

The Bioscop is a movie projector developed in 1895 by German inventors and filmmakers Max Skladanowsky and his brother Emil Skladanowsky (1866–1945).

Blackout (fabric)

Blackout refers to a foam-backed, opaque fabric used to black out light. Blackout fabrics are most commonly found in hotel rooms as curtain linings or drapery fabrics, blocking much of the light that would otherwise enter through a window when the curtains are closed. For travelers, third shift workers, and parents of babies, blackout is an essential element in the bedroom. Besides window coverings, other uses for blackout fabrics include wallpaper, movie projector screens and planetarium domes.

Film projector (disambiguation)

A film projector or movie projector is a device used for projection of moving images from film.

Film projector may also refer to:

Slide projector for projection of still images from film

Film session

A film session involves the use of a 35 mm movie projector and/or VCR/DVD/DVR player to project images portrayed of a sporting event. The visual analysis of an upcoming game or previous game by the coaching staff with or without players.

The term was coined by the NFL in reference to making a better defense or offense while preparing for the next Sunday opponent by choreographing the weaknesses shown by the game tape thus opening up the chances for more opportunities of success.

Film Session is also the name of an NFL Network television program exploring the depths of the massive NFL Films library showcasing many of its classic, modern and historical specials and documentaries chronicling the history of the American sport of football in the National football league.

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.

Max Skladanowsky

Max Skladanowsky (30 April 1863 – 30 November 1939) was a German inventor and early filmmaker. Along with his brother Emil, he invented the Bioscop, an early movie projector the Skladanowsky brothers used to display the first moving picture show to a paying audience on 1 November 1895, shortly before the public debut of the Lumière Brothers' Cinématographe in Paris on 28 December 1895.

Movie camera

The movie camera, film camera or cine-camera is a type of photographic camera which takes a rapid sequence of photographs on an image sensor or on a film. In contrast to a still camera, which captures a single snapshot at a time, the movie camera takes a series of images; each image constitutes a "frame". This is accomplished through an intermittent mechanism. The frames are later played back in a movie projector at a specific speed, called the frame rate (number of frames per second). While viewing at a particular frame rate, a person's eyes and brain merge the separate pictures to create the illusion of motion.Since the 2000s, film-based movie cameras have been largely (but not completely) replaced by digital movie cameras.

Open matte

Open matte is a filming technique that involves matting out the top and bottom of the film frame in the movie projector (known as a soft matte) for the widescreen theatrical release and then scanning the film without a matte (at Academy ratio) for a full screen home video release.

Usually, non-anamorphic 4-perf films are filmed directly on the entire full frame silent aperture gate (1.33:1). When a married print is created, this frame is slightly re-cropped by the frame line and optical soundtrack down to Academy ratio (1.37:1). The movie projector then uses an aperture mask to soft matte the Academy frame to the intended aspect ratio (1.85:1 or 1.66:1). When the 4:3 full-screen video master is created, many filmmakers may prefer to use the full Academy frame ("open matte") instead of creating a pan and scan version from within the 1.85 framing. Because the framing is increased vertically in the open matte process, the decision to use it needs to be made prior to shooting, so that the camera operator can frame for 1.85:1 and "protect" for 4:3; otherwise unintended objects such as boom microphones, cables, and light stands may appear in the open matte frame, thus requiring some amount of pan and scan in some or all scenes. Additionally, the un-matted 4:3 version will often throw off an otherwise tightly-framed shot and add an inordinate amount of headroom above actors (particularly with 1.85:1).

Open-matte doesn't happen as often with films presented in 2.20:1 or 2.39:1. Instead those employ pan and scan. Many films over the years have used this technique, the most prominent of which include Schindler's List, Titanic, and Top Gun. Stanley Kubrick also used this technique for his last five films (A Clockwork Orange (1971), Barry Lyndon (1975), The Shining (1980), Full Metal Jacket (1987) and Eyes Wide Shut (1999).) James Cameron's Terminator 2: Judgment Day (1991) is also an example of open-matte.

Outdoor cinema

An outdoor cinema consists of a digital or analog movie projector, scaffolded construction or inflatable movie screen, and sound system.

Outdoor cinemas first began at around 1916 in Berlin, Germany.Viewers usually sit on camping chairs or blankets. Some Hollywood world premieres were screened in outdoor cinemas – sometimes with the stars in attendance. Most screenings are free with some raising money for charities.

As projector prices have decreased, guerrilla style outdoor cinemas have become more common. These are run on a very small budget by groups of amateurs. It is common for the events to be organised online, participants then meet in parks, empty parking lots or other public places. Guerrilla outdoor cinemas are very basic, often needing to be completely set up and dismantled in a single night. Sheets, portable screens or existing walls are used as a screen for the projected image. Power is obtained from generators or car batteries.

These kind of cinemas are very popular in Greece during the summer period with at least 90 operating in Athens, as of 2015.In the Sixties, the city used to host more than 600 outdoor cinemas.

Projector

A projector or image projector is an optical device that projects an image (or moving images) onto a surface, commonly a projection screen. Most projectors create an image by shining a light through a small transparent lens, but some newer types of projectors can project the image directly, by using lasers. A virtual retinal display, or retinal projector, is a projector that projects an image directly on the retina instead of using an external projection screen.

The most common type of projector used today is called a video projector. Video projectors are digital replacements for earlier types of projectors such as slide projectors and overhead projectors. These earlier types of projectors were mostly replaced with digital video projectors throughout the 1990s and early 2000s, but old analog projectors are still used at some places. The newest types of projectors are handheld projectors that use lasers or LEDs to project images. Their projections are hard to see if there is too much ambient light.

Movie theaters used a type of projector called a movie projector, nowadays mostly replaced with digital cinema video projectors.

Refresh rate

The refresh rate (most commonly the "vertical refresh rate", "vertical scan rate" for cathode ray tubes) is the number of times in a second that a display hardware updates its buffer. This is distinct from the measure of frame rate. The refresh rate includes the repeated drawing of identical frames, while frame rate measures how often a video source can feed an entire frame of new data to a display.

For example, most movie projectors advance from one frame to the next one 24 times each second. But each frame is illuminated two or three times before the next frame is projected using a shutter in front of its lamp. As a result, the movie projector runs at 24 frames per second, but has a 48 or 72 Hz refresh rate.

On cathode ray tube (CRT) displays, increasing the refresh rate decreases flickering, thereby reducing eye strain. However, if a refresh rate is specified that is beyond what is recommended for the display, damage to the display can occur.For computer programs or telemetry, the term is also applied to how frequently a datum is updated with a new external value from another source (for example; a shared public spreadsheet or hardware feed).

Richard Hollingshead

Richard Milton Hollingshead, Jr. (February 25, 1900 - May 13, 1975) was the inventor of the drive-in theater.

In the early 1930s, he was working as a sales manager in his father's auto parts company, Whiz Auto Products. According to one story, his mother was a large woman who was uncomfortable sitting in a regular movie theater. So he began experimenting at his home in Camden, New Jersey, using his car, a 1928 Kodak movie projector, and two sheets nailed between two trees for a screen. Eventually, he came up with a ramp in each parking space, so that patrons could elevate the front of their cars to see the screen without being blocked by other vehicles. He applied for a patent on August 6, 1932 and was granted number 1,909,537 on May 16, 1933.

With three investors, his cousin John Smith, Edward Ellies, and Oliver Willets, he formed a company called Park-It Theatres, Inc. Their 400-acre (1.6 km2) "Automobile Movie Theatre" opened on Admiral Wilson Boulevard in Camden on June 6, 1933. RCA Victor provided three six foot (1.8 m) by six foot speakers to go with the 40 foot (12 m) by 50 foot (15 m) screen. The first movie shown was Wives Beware, starring Adolphe Menjou. The charge was $0.25 per person and $0.25 per automobile, with a maximum cost of $1. Hollingshead sold the theatre in 1935 and opened another one.

Park-It Theatres licensed the concept to Loews Drive-In Theatres, Inc., but had trouble collecting royalties in 1937. Eventually, after Loews was taken to court, Hollingshead's patent was ruled invalid in 1950.

Shutter (photography)

In photography, a shutter is a device that allows light to pass for a determined period, exposing photographic film or a photosensitive digital sensor to light in order to capture a permanent image of a scene. A shutter can also be used to allow pulses of light to pass outwards, as seen in a movie projector or a signal lamp. A shutter of variable speed is used to control exposure time of the film. The shutter is constructed so that it automatically closes after a certain required time interval. The speed of the shutter is controlled by a ring outside the camera, on which various timings are marked.

Sound-on-disc

Sound-on-disc is a class of sound film processes using a phonograph or other disc to record or play back sound in sync with a motion picture. Early sound-on-disc systems used a mechanical interlock with the movie projector, while more recent systems use timecode.

Static interpretation of time

The static interpretation of time is a view of time which arose in the early years of the 20th century from Einstein's special relativity and Hermann Minkowski's extension of special relativity in which time and space were famously united in physicists' thinking as spacetime.

Essentially the universe is regarded as akin to a reel of film – which is a wholly static physical object – but which when played through a movie projector conjures a world of movement, color, light and change. In the static view our whole universe – our past, present, and future are fixed parts of that reel of film, and the projector is our consciousness. But the 'happenings' of our consciousness have no objective significance – the objective universe does not happen, it simply exists in its entirety, albeit perceived from within as a world of changes.

The alternative, and commonly assumed view, is that the world unfolds in existence, that our present has some wider physical significance, because the universe evolves in step with it.

The static view is the simpler in that all that is held to exist is the physical ordering of the universe. All that there is at every time simply exists. The unfolding view requires an additional quality to the universe – that besides the physical ordering there is some quality of coming into and out of existence.

One can argue that the onus is therefore upon those who propose it, that the world unfolds, and that this additional quality they hold to (absent from special relativity) is indeed a physical feature of the world. There is however as yet no proof, experiment, or measurement, to show that our conscious experience of an unfolding present has any objective physical significance, or that the universe is anything other than static.

The static view is however commonly rejected for psychological, not scientific reasons, because it leads to a fatalistic or "fixed" conclusion about human existence – our 'past', 'present', and 'future' being what they are – there is no contingency in the world and no possibility of 'altering' or creating the future through some act of will – the future exists. It is simply that our consciousness has not yet reached it.

Steenbeck

Steenbeck is a company that manufactures flatbed editors. Steenbeck is brand name that has become synonymous with a type of flatbed film editing suite which is usable with both 16 mm and 35 mm optical sound and magnetic sound film.The Steenbeck company was founded in 1931 by Wilhelm Steenbeck in Hamburg, Germany. Since then, Steenbeck editing tables have become ubiquitous in the film editing community and have seen significant use in television production, including at the BBC's Ealing-based Film Department . In total, more than 25,000 machines are in operation around the world. The company relocated to Venray (The Netherlands) in September 2003, where it still manufactures editing tables.

Despite the move away from physical film stock – much editing is now based on digital media – devices such as the Lightworks non-linear film editing controller and archives still use the Steenbeck physical layout for controlling the process. The Steenbeck's lower light levels and controllable speed make it a preferred piece of equipment for film archives (such as the Library of Congress' motion picture collection) and restoration facilities as prints can be quickly and easily inspected with less risk of damage compared to a movie projector. Because there is no intermittent movement, the image is created through a rotating prism which scans the frames. Steenbeck machines were known to be exceptionally easy on film stock, due to their use of soft-edged nylon rollers.

Wobbies World

Wobbies World was an amusement park which operated from about 1970 to the late 1990s in the Melbourne suburb of Vermont South, Australia.

The park consisted of many custom-built attractions, most slow moving and aimed at very young children. The park had some characteristic modes of transport including a helicopter "Whirliebird" monorail circuit, mower motor driven 6 wheeler ATVs, a real Bell helicopter refurbished as a ground-mounted simulator, a "Splashdown" mini log ride, a mini-golf course, trampolines, a ball pit, several food and drink kiosks, a miniature train circuit, a miniature car circuit, four Melbourne W2 class trams and a large Vickers Viscount propeller plane fitted out as a movie-projector simulator. The plane now resides at the Australian National Aviation Museum, in Moorabbin, while the Bell helicopter is dismantled and currently sits in a paddock on Dandenong–Frankston Road at 38°03′57″S 145°12′02″E. One of the Whirliebird helicopters now resides in the front yard of a private residence [1]

Despite memorable television advertisements over the decades, the park slowly deteriorated in the mid to late 1990s and had closed down by the end of the decade. Its demise has been linked to the high entrance fee for the time ($36 for a family of four in 1994) and the charging of separate fees to use some of the attractions.

A plant nursery and the Saxon Wood town house estate occupied the Springvale Road site, but the entrance gate (without road), concrete castle, bridges, a train station, the Birthday Room and the miniature golf course from the former amusement park still remained within the nursery.

In September 2012, the state government announced that a new Forest Hill police station was to be built on the site. The plant nursery has now closed.

The site is now the location of the new Forest Hill Police Station.

Zoopraxiscope

The zoöpraxiscope (initially named zoographiscope and zoogyroscope) is an early device for displaying moving images and is considered an important predecessor of the movie projector. It was conceived by photographic pioneer Eadweard Muybridge in 1879 (and built for him by January 1880 to project his famous chronophotographic pictures in motion and thus prove that these were authentic). Muybridge used the projector in his public lectures from 1880 to 1895. The projector used 16" glass disks onto which Muybridge had an unidentified artist paint the sequences as silhouettes. This technique eliminated the backgrounds and enabled the creation of fanciful combinations and additional imaginary elements. Only one disk used photographic images, of a horse skeleton posed in different positions. A later series of 12" discs, made in 1892–1894, used outlines drawn by Erwin F. Faber that were printed onto the discs photographically, then colored by hand. These colored discs were probably never used in Muybridge's lectures. All images of the known 71 disks, including those of the photographic disk, were rendered in elongated form to compensate the distortion of the projection. The projector was related to other projecting phenakistiscopes and used some slotted metal shutter discs that were interchangeable for different picture disks or different effects on the screen. The machine was hand-cranked.The device appears to have been one of the primary inspirations for Thomas Edison and William Kennedy Dickson's Kinetoscope, the first commercial film exhibition system. Images from all of the known seventy-one surviving zoopraxiscope discs have been reproduced in the book Eadweard Muybridge: The Kingston Museum Bequest (The Projection Box, 2004).

...it is the first apparatus ever used, or constructed, for synthetically demonstrating movements analytically photographed from life, and in its resulting effects is the prototype of the various instruments which, under a variety of names, are used for a similar purpose at the present day.

As stipulated in Muybridge's will the original machine and disks in his possession were left to Kingston upon Thames, where they are still kept in the Kingston Museum Muybridge Bequest Collection (except for four discs that are in other collections, including those of the Cinémathèque française and the National Technical Museum in Prague).Muybridge also produced a series of 50 different paper 'Zoopraxiscope discs' (basically phenakistiscopes), again with pictures drawn by Erwin F. Faber. The discs were intended for sale at the 1893 World's Fair at Chicago, but seem to have sold very poorly and are quite rare. The discs were printed in black-and-white, with twelve different discs also produced as chromolithographed versions. Of the coloured versions only four different ones are known to still exist with a total of five or six extant copies.

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