In 1824, Mark Roget, who was also responsible for Roget’s Thesaurus, was in the basement of his home in Bloomsbury when a carriage passed by. He noticed a curious visual effect, caused by the spinning spokes of the carriage wheels and the Venetian blinds at his window. This led to a paper entitled The Persistence of Vision With Regard To Moving Objects, in which he describes how the eye’s persistence of vision causes an image to stay on the retina for a short time after the event.
During the 19th century various attempts were made to create the illusion of a moving image by exploiting this effect. Some of the most successful devices employed flick cards, a succession of cards containing slightly different drawn images, that were flicked rapidly in front of the viewer’s eyes. Numerous other devices were invented, although none were successful.
The real pioneer of moving pictures was Eadweard Muybridge. Between 1872 and 1877 he created sequences of still pictures at racetracks by stringing wires across the track, each coupled to the shutter of a separate camera. The developed pictures were then attached to a stroboscopic disk and shown using a magic lantern, producing an illusion of moving horses. By 1882, Etienne-Jules Marey had developed this idea into a special machine that replaced all of the individual cameras.
In 1888, W K L Dickson, working for Thomas Edison, tried to record photographs on wax cylinders. A year later, he was investigating the celluloid film produced by George Eastman: and by 1892 he was creating 15-second films using Edison’s Kinetograph camera. The pictures it produced could be viewed on a portable ‘peep’ machine known as the Kinetoscope. These devices used a film 35 mm wide containing a image of 25 mm by 19 mm, soon accepted as the standard type of cinema film.
This form of movie camera had two spools, containing sprocketed film that was ‘cranked’ through the device by hand. Although the film moved at a steady speed determined by the cameraman, it jerked through the film plane, or gate mechanism, on a frame-by-frame basis. This mechanism advanced the film by one frame, opened the shutter to expose the film to an image created by the camera’s lens and then closed it again, allowing the film to move on to the next frame.
Having exposed the film, it would be developed in a similar way to normal photographic material, except that the results would be transferred as a positive image onto another length of sprocketed film. In later years this was played back in a special film projector, containing a powerful lamp, a gate mechanism similar to that used in the camera and a projector lens.
The hand-cranking of early cameras wasn’t entirely satisfactory, especially since some camera operators turned the handle slowly to conserve film or were unable to maintain a steady speed. As a result, many older films seem to move fast or have a jerky action. However, with the introduction of electric motors and improved technology the motion-picture camera gave very good results.
Since Edison’s products weren’t patented in Europe they were developed further by Louis and Auguste Lumiere. The result was the Cinematographe, a portable camera that also worked as a printer and projector. On December 28, 1895, several films were shown to a paying audience in the basement of the Grand Café, Paris. By the end of the century, 35 mm film, running at 16 frames per second, was commonly employed, although most scenes only lasted for between 15 and 60 seconds.
And as early as 1902, in his film A Trip to the Moon, Georges Melies created special effects, usually by stopping the camera, changing the scene and starting it again. By 1905, the nickelodeon became popular in the USA, starting a major expansion of the industry between 1908 and 1918.
As early as the 1890’s, Thomas Edison had created talking kinetoscopes, films that were accompanied by sound recorded on cylinder phonographs. Unfortunately, the technology of the time was incapable of developing this idea to fill an entire auditorium with sound.
Inevitably, this meant that all early films were silent, requiring the cinema to provide suitable background music, often in the form of a musician playing a piano. Several further attempts were made to synchronise a film with a phonograph record, but with varying degrees of success. However, by 1926, Warner Brothers employed the Vitaphone system to add phonographic sound to a silent film. Late in 1927, they released The Jazz Singer, a part talkie, using several musical and talking sequences, followed in 1928 by Lights of New York, which incorporated a full sound track.
The big breakthrough, heralding the age of the talkies, came with the introduction of a sound track recorded on the film itself. This only became possible after Lee De Forest invented the Audion vacuum tube, also known as an electronic valve, allowing the electrical amplification of sound.
During the twenties, De Forest went on to develop the Phonofilm system, adopted by all major film makers by 1930. This employed an optical sound track, located between the picture frame and the sprocket holes. During recording, a pair of metal ribbons flexed in sympathy with the sound, changing the track’s exposure to light. Most 35 mm films used variable-area recording, in which the width of the track varied with sound intensity, although other films used variable-density recording.
During playback, a special sound lamp in the projector illuminated the sound track. The light passing through the film would then vary in sympathy with the original recording, being converted back into an electrical signal by means of a photocell. In order to give acceptable results such films ran at sound speed, a frame rate of 24 frm/s. However, in Europe and other areas that were supplied with a 50 Hz AC mains supply, an alternative speed of 25 frm/s was commonly used.
Sadly, the sound quality of optical recordings left a lot to be desired. Firstly, it was difficult to move the film past the optical sensor at a steady speed, especially as it was located in close proximity to the gate mechanism. Secondly, the adjacent sprockets could cause audible buzzing on the sound output. Worst of all, the optical sound tracks were very noisy at high frequencies, which led to the universal adoption of the Academy roll-off at all cinemas. In essence, this removed most of the upper end of the sound spectrum, resulting in a characteristic muffled sound.
After the fifties, magnetic sound tracks were used, especially on 70 mm film. This involved the application of iron oxide strips to the film after it had been developed. Unfortunately, the fixing of this magnetic material, similar to that used in a tape recorder, wasn’t always reliable. Up to six tracks could be used, as in Dolby Surround Sound, and exploited to create special effects and ambience.
The nineties saw the arrival of digital recording, usually in the form of Dolby SR-D, also known as Dolby Digital. This accommodates five channels of surround sound in the form of dots and dashes that are actually located between the film’s sprocket holes, allowing standard tracks to be provided as well. By using perceptual coding the data rate is kept to just 320 KB per second.
Quality and image size is determined by the width of film. Professionals have always used 35 mm or 70 mm film, semi-professionals have used 16 mm and amateurs once employed 8 mm. The frame rate, measured in frames per second (frm/s or fps), can also vary. For professional work, where sound is required and flicker can’t be tolerated, a standard rate of 24 frm/s has been adopted, although older semi-professional and amateur films run at a rather more economic 16 frm/s.
The aspect ratio (the relationship between picture width and height) of movies produced between 1895 and 1955 was set at
4:3, similar to that used for ‘landscape’ still pictures. This ratio was also employed in the original forms of analogue television broadcasting.
However, 1953 saw the introduction of Cinemascope, which used an anamorphic lens in the film camera, condensing a much wider image onto standard 35 mm film. The matching projector was fitted with a complementary lens that created an aspect ratio of
2.35:1. Other contemporary systems included Todd-AO, employing 70 mm film, and Cinerama, using three synchronised 35 mm cameras and matching projectors. Other wide screen formats, including the common aspect ratio of
16:9, often involve the use of 70 mm film. More recent systems include the IMAX and OMNIMAX family, as well as the 70 mm Disney 3D system.
Attempts to introduce three-dimensional (3D) films in the fifties were unsuccessful. The more recent Disney 3D system uses two synchronised cameras and projectors to create a stereo image, using a proprietary aspect ratio and format on 70 mm film. Unfortunately, both Disney 3D and IMAX 3D films can only be viewed in special theatres and require the use of polaroid goggles.
1997 Grolier Multimedia Encyclopedia, © 1997, Grolier Inc.
Daily Mail, July 11, 2002: Letter from Mimi Romilly
©Ray White 2004.