35mm film
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35 mm film (also called normal film ) is a film format in which the film strip is 35 mm wide. It was originally developed for the recording of moving images ( cinema films ), only later was it also used in still photography as 35mm film ( 35mm film , 135 ). In both areas it became the most widely used film format.
Since the end of the 20th century, the technology of photochemical films has been largely superseded by digital production methods, both in still photography and in motion pictures . In digital cameras, however, the 24 mm × 36 mm image format lives on from the 35 mm film format in the dimensions of the full-format sensors .
construction
Similar to roll film , the film strip is wound onto a plastic (formerly metal) spool, but then packed in a light-tight sheet metal cartridge. Up until the 1950s, it was quite common to assemble such film cartridges yourself from 35 mm yard goods. The film cartridge is inserted directly into the 35mm camera. With simple cameras, and in some cases with better ones until the 1980s, this insertion - especially the threading of the film tongue protruding from the cartridge onto the take-up reel - could demand a nerve-wracking amount of patience and skill from the non-professional, casual photographer. In 1967 the PL system (Pentacon loading) was introduced to Praktica cameras. When the 35mm cameras were largely equipped with motorized film transport, threading was usually done automatically.
Separate, interchangeable film magazines , as are common with medium format cameras , are only available in exceptional cases. However, some manufacturers offer so-called long film magazines for a few professional SLR cameras with a stock of 100 or even 250 images, which are attached instead of the normal camera back.
The film strip must be rewound into the cartridge after exposure so that it is not exposed to ambient light when it is removed from the film chamber; a film change in between is possible, but relatively time-consuming. To rewind, one or more release levers (usually on the underside of the housing) have to be activated so that the spiked roller, which is usually responsible for propulsion, disengages until the next exposure (on the new film).
When rewinding, the film tongue usually disappears completely into the cartridge for safety's sake, which is intended to prevent re-use of already exposed films, but also carries a higher risk of stray light falling into the cartridge, since the film no longer closes the cartridge mouth as tightly. For this reason, KB cartridges are always sold in an additional box by all manufacturers. An accidentally pulled in film tongue can be pulled out again with a film retractor or a suitably bent paper clip.
With some SLR cameras with automatic film transport, you can often specify within the framework of special user settings whether the film should be automatically rewound after the last exposure or whether the process should only be triggered manually by pressing a button when the end of the film is reached. In this context, you can usually also define whether the film tongue can generally be rewound into the cartridge or not, or whether this should only happen when rewinding is triggered manually. With some cameras, the rewind speed can also be preselected (and partly adjusted during the rewind process); Fast transport, if the readiness for re-use is in the foreground, slow, if the noise (e.g. in a church) must not be a nuisance.
Some modern cameras also have devices that prevent a film from being exposed by accidentally opening the back wall. Some compact cameras trigger an automatic rewind process when you try to open the back cover. Other cameras hide the rolled-up film under a protective flap, so that in the best case only three to four images are exposed when opening.
Even if nothing changes in this basic principle, some manufacturers offer special functions worth mentioning in this context. With some modern SLR cameras, for example, the film is forwarded to the last picture immediately after it has been inserted and then gradually pulled back into the cartridge after each shot. The advantage is that the length of the film is already determined exactly for the camera after it has been inserted (and, for example, enables a residual image to be displayed even without a DX code ), so that all already exposed images in the cartridge are safe from accidentally opening the back wall and that the unpleasant rewinding noise may unexpectedly disappear while taking a photo.
Other cameras offer a so-called mid-reload function , with which the film can be rewound into the cartridge at any time and, for example, rewound exactly to the old image position after a film change - with a positioning accuracy of better than one millimeter.
Even when using long film magazines, the procedure differs in part from the normal process outlined above, in that rewinding of the film is generally not required. For example, the film is reeled directly from a filled special cartridge into an identical empty cartridge, which can in principle also be removed individually, but can remain in a special double insert for an even faster film change, which can simply be exchanged for another prepared double insert while taking the picture .
Assembly
Cartridges with rewind
For daylight photography , 35mm film is available as black and white film , color negative film and slide film . In addition, there are artificial light film for special applications , which enables color-correct reproduction in artificial light with a lower color temperature, and infrared film for infrared photography , which is sensitized to the infrared components of the electromagnetic spectrum .
Commercially available configurations include 12, 24 and 36 images (approx. 1.6 m). With its own perforation (different from cinema film) and in film cartridges , Kodak introduced the designation 135 for the film type ( ISO 1007) in 1934 .
Some films with a thinner substrate (such as the Ilford HP5 or the Kodak Technical Pan) were sometimes also available with 72 images per cartridge. With many cameras, however, a few more pictures can be taken than stated on the film, but there is a risk that photos at the beginning of the film will be rendered unusable by light falling through the cartridge slot.
In addition, in the case of films which are developed in automatic machines, there is the risk that the last image becomes unusable as a result of the bonding of successive films. This effect occurs to a greater extent with particularly compact cameras such as Rollei 35 or Minox 35 .
Another possibility of error is that if the manual winding is too powerful at the end of the film, the transport teeth slip or the perforation is torn through and, if this is not noticed or further photography is not omitted, another exposure then takes place, overlapping with the correctly performed penultimate one, which naturally damages them.
Motion picture
A motion picture film is photographic film for moving pictures (motion pictures), further developed from roll film and provided with perforation . From the beginning up to the early 1950s it was mostly a matter of flammable nitrocellulose material , then increasingly a security film made of cellulose acetate and now more and more security film on polyester PETP .
By the meter
As a special form, 35mm film is available by the meter (e.g. 17 or 30.5 meters), which you can assemble yourself (reel into the film cartridge), for example for
- Surveillance cameras,
- SLR cameras with special long film magazines or
- for self-assembly in standard film cartridges for photographers who take a lot of photos and want to save money.
Agfa Rapid / SL system
Agfa Rapid was a system on normal 35mm film in a special cassette which was not compatible with the conventional 35mm film cartridge. The film in the camera was pulled from one film cartridge into the other.
Even with the SL system (rapid loading system) developed in the GDR , the film was drawn from one film cartridge inside the camera into a second cartridge. Rewind was not required. There were special cameras for the SL system. The SL system has not been available since the end of the GDR.
Like the Agfa Rapid system, the SL system is based on the Agfa Karat system from the pre-war period. The three formats are technically largely identical and may even be interchangeable in many cameras. Again they are based on the Ansco memo cartridge system.
Recording format
Cinema film format
When originally used for movies, the roll of film was exposed “across”. The material width of 35 mm cannot be fully used, as around 4 mm cannot be used due to the perforations on both sides. There is also a 1/10 inch (2.54 mm) wide strip for the sound track. About 24 mm remain for recording the image, so common recording formats for films were, for example, 22 mm × 18 mm, 22 mm × 16 mm or 23.66 mm × 17.78 mm.
Photo film format
The typical recording format (picture format) for still pictures on 35mm film, however, is 24 mm × 36 mm, but there are also some special forms:
- Half-frame cameras use 35 mm film that is 18 mm × 24 mm; this format corresponds to the 35 mm cinema film originally used (number of frames: 24, 48 or 72);
- the Revue Auto-Reflex, built by Konica for the Quelle mail order company , could be switched between half format and normal 35 mm format;
- many cameras from Robot as well as the Tenax I built by Zeiss Ikon exposed the film in a square of 24 mm × 24 mm;
- Panorama cameras use 35 mm film, for example, with the format 24 mm × 56 mm, or 24 mm × 58 mm (HORIZON 202 camera), or 24 mm × 65 mm (for example Hasselblad XPan, or “NOBLEX 135”);
- some Russian / Ukrainian 35mm SLR cameras use a slightly larger film format, probably 25mm x 36mm (as reflected, for example, in the existence of the Peleng Circular Fisheye, which illuminates a slightly larger image circle);
- Stereo cameras that take two pictures at once with slightly different perspectives sometimes use other formats such as 24 mm × 28 mm, 24 mm × 30 mm or 24 mm × 24 mm on 35mm film.
History and Development
The 35 mm wide film strip with double-sided perforation for film transport was introduced by William Dickson in 1893 . Since then, it has been the most widely used film format for cinema films.
At the beginning of the 20th century there were various attempts to construct photo cameras for the use of perforated cinema film with a width of 35 mm. In 1913, Oskar Barnack developed the first prototype of such a camera for Leitz (“Ur- Leica ”). The original purpose of the device was to wrap short film strips of the same raw film on the film set in a so-called "35mm cartridge" and to expose them independently of the large film camera in order to illuminate a scene that was to be shot the next day together with the material of the shot Day in the copier factory and thus be able to check before shooting. In addition, still photos could now be made in the same way.
The 35 mm format of 24 mm × 36 mm resulted from doubling the silent film cinema format (18 mm × 24 mm) by "laying the film sideways": In a film camera, the film runs vertically past the picture window , so the perforation is on the left and right; In a photo camera, on the other hand, the film material is guided horizontally, so the perforation is above and below. The small-format photography become popular, particularly in the field of photojournalism quickly. It allowed the use of new stylistic means. The photographer Paul Wolff was a pioneer in this field . The Leica quickly separated from the film set; this format made cameras compact enough to be easily taken anywhere; other manufacturers soon followed. Reportage photography received decisive impulses from the capacity of up to 36 photos per film.
As for plates, sheet or roll film in the format 6 cm × 9 cm × 4 cm, there were folding cameras from Voigtländer and Agfa in the 1950s and 1960s for 35mm film. They were particularly compact, but were cumbersome to use and technically vulnerable (folding mechanism, leakage on the bellows , lens standard that could not be precisely fixed ). With the Minox 35 as the smallest 35mm camera in the world, the principle of the folding camera, but without bellows, was still in production until 2002.
See also
- Kinetoscope
- Image format (paper image) - paper formats for 35mm photography
- Image resolution
- 35 millimeter adapter
literature
- John Belton: The Origins of 35mm Film as a Standard . In: SMPTE Journal . Vol. 99 August 1990, ISSN 0036-1682 , p. 652–661 (great caution is advised: legend to Figure 10 misleading, also errors to Dickson and Lauste (pp. 657f.)).
- Matthias A. Uhlig: Manual of the film camera technology. Camera Obscura Verlag Uhlig, Waschow 2007, ISBN 978-3-9807533-1-9 .
Web links
- Historical film formats (English)
Individual evidence
- ^ The History of Kodak Roll Films . Archived from the original on February 22, 2009. Retrieved February 8, 2009.
