Several frame rates are used in these formats: films shot for silent projection (no sound-on-film) are usually photographed at 16 frames per second (fps), 18 fps, or 24 fps. Films shot for sound-on-film projection run at 18 fps, or, more commonly, 24 fps. Different cameras provide different combinations of shooting rates.
Regular 8mm commonly comes in 25' and 50' spools, as well as 100' spools
(although the Bolex regular 8mm is the only camera which takes the 100'
spools). Super 8mm comes in 50' and, less commonly, 200' cartridges. Most
cameras are only capable of accepting the 50' cartridge, though. Eastman
Kodak (tm) once produced super 8mm `sound' cartridges, which contained
film with pre-applied magnetic stripes along the edges, designed to be
recorded in camera. Production of new pre-striped super 8mm film was discontinued
in the fall of 1997, due to lack of demand.
regular 8mm film frame: super 8mm film frame: (note big perforations) (note small perforation) | | | | | -------------- O | | ---------------- | | | Small | | | | Larger | | | | Image | | | | Image |o| <--- Smaller | | Area | | | | Area | | Perforation | -------------- O | | ---------------- | | | | | |<------ 8mm ----->| |<------ 8mm ----->|
The film itself comes either wound tightly around a plastic `core,' for loading into a camera magazine (either in a darkroom, or a portable `changing bag'), or, for 100' and 200' lengths, mounted on small metal spools (like those for regular 8mm), which can be loaded into the camera in moderately bright daylight. Professionals usually use 400' and (rarely) 1200' lengths of the film. (The Panavision 16 is the only currently-available camera which will take the 1200' rolls; old newsreel cameras, such as the Auricon (which is still available on the used market), also can take this large size).
Films shot in 16mm almost always run at 24 frames per second (fps), with the exception of many silent home movies which are sometimes shot at 16 fps. European television films are photographed at 25 fps to match the frame rate of the PAL television standard. Occasionally, U.S. television films are shot at 29.97 fps or 23.976 fps to match or nearly match the TV standard, respectively.
As with super 8mm, magnetic-striped 16mm raw stock was once available for use in cameras with built-in recording heads, although pre-striped stock is no longer available. It was primarily used for TV newsfilm applications, until 3/4" videotape replaced 16mm for newsgathering in the late 1970's/early 1980's.
Some producers are shooting TV shows on super 16mm, with the intent
of re-transferring the negatives to videotape when and if high definition
television (HDTV) comes into widespread use. The wider aspect ratio is
very close to the proposed U.S. HDTV standard of 1.77:1 (16/9), and so
super 16mm films could be shown with little cropping, whereas a 1.37:1
picture would either have the top and bottom edges cropped, or the sides
masked inward to fit on an HDTV screen (yielding a very small picture).
Presumably, then, super 16mm is a way for producers worried about upcoming
technological changes in television to `future proof' a television show,
so that it can be presented in any form, with the highest quality images
allowed by the format chosen for future TV receivers.
16mm film frame: super 16mm film frame: | | | | | O--------------O | |-----------------O| | | Image | | Image area -->| Image || | | Area | | extends to | Area || | O--------------O | edge of |-----------------O| | | film. | | |<----- 16mm ----->| |<----- 16mm ----->|
During the `wide screen' craze of the late 1950's and early 1960's, anamorphic cinematography (a.k.a. `CinemaScope (tm) ,' and, later, `Panavision (tm) ') became commonplace. In order to advertise their films as being `wide screen' movies, many producers who had a large collection of yet-to-be-released 1.37:1 films just cropped off the top and bottom edges of the frame (including titles and other important elements), leaving a 1.66:1 or 1.85:1 ratio movie. Later, continuing through the present, non-anamorphic (`flat') films were composed to fit on a 1.85:1 screen. These films, however, are still photographed with an Academy camera frame, although the camera's viewfinder usually does not show the top and bottom edges. Occasionally, a 'hard matte' is used in the camera or printer, masking off the top and bottom edges of the frame. When films are shot `soft matte,' projection errors can cause undesired elements (such as boom microphones) to show up in the frame; sometimes, extra area above and below the intended framelines is visible in TV broadcasts of thse films, as well.
Nearly all 35mm film is shipped wound around plastic cores, and it comes in 200', 400', and 1000' lengths. Small 100' metal spools are also available, for use in small windup cameras like the Bell and Howell (tm) Eyemo.
Most 35mm sound films are shot at 24 fps, as the faster frame rate both improves the sound quality (with respect to the synchronization with the image-lower frame rates look strange with lip-sync sound). As with 16mm, though, some European television films are shot at 25 fps, to match the TV frame rate, and some US television films are shot at 29.97 or 23.976 fps, to match or nearly match the U.S. TV frame rate, respectively.
It should be noted that sound is never recorded directly on the 35mm film while shooting-filming is done in `double system' fashion, usually using a crystal-controlled camera motor which runs at an exact speed, along with a crystal-controlled 1/4" tape machine (usually a Nagra 4.2) or DAT machine.
The disadvantage to shooting in anamorphic is usually that the lenses used introduce weird types of distortion and lack the depth of field (front to rear sharpness) of standard `spherical' lenses. For example, a night scene in a film might contain out-of-focus points of light in the background; if they were filmed with spherical lenses, the lights would appear to be circular, but would appear to be vertical ellipses if they were filmed with anamorphic lenses.
Anamorphic cinematography is still in common usage for major theatrical films, and is often indicated by the phrase `filmed in Panavision (tm) ' (if the lenses/cameras were made by Panavision (tm) ), which has displaced `CinemaScope (tm) ' as the usual term for this process, although many people still refer to anamorphic films as `scope' films. It is worth noting, though, that companies other than Panavision (tm) manufacture, rent, and sell anamorphic camera lenses. Also, the phrase `filmed with Panavision (tm) cameras and lenses' indicates that Panavision (tm) gear was used, but the film is not in anamorphic (they rent spherical [non-anamorphic] lenses, too).
The actual prints made from this format (at the time when it was common for features) were intended to be projected in a variety of aspect ratios. Common ones include: 1.66:1, 1.85:1, and 2:1. Other aspect ratios were used for projection as well, but never gained wide acceptance.
Super 35mm is also used by some directors and cinematographers because they feel that it allows for a less problematic full-screen television version of the film. Because super 35mm negatives carry more picture than will eventually be projected, a nicer-looking TV version of the film can be created. This works by manipulating the area of the film which is displayed on the television screen, using the extra picture at the top and bottom of the frame to `fill in' areas which would ordinarily lack a portion of the image, when the TV frame must center on a specific area at the edge of the theatrical frame.
Super 35mm prints can be 'extracted' from various portions of the negative. A `top-extraction' or `common headroom' extraction is made such that the very top frameline of the super 35mm negative corresponds to the very top frameline of the print. A `symmetrical' or `center- extraction' print is made such that equal top and bottom areas are cropped off of the super 35mm negative. The viewfinder markings are adjusted to match the chosen format.
Interestingly, super 35mm is nearly identical to the `Superscope 235'
process used in by RKO Pictures. The first film to use this format was
Run
for the Sun in 1956. This was photographed using almost the same frame
area as Super 35mm, and then optically printed onto CinemaScope (tm) release
prints, leaving extra image area at the top and bottom of the frame for
TV prints.
35mm film frame: 35mm film frame: (Academy ratio) (1.85:1 ratio) (note inefficient use of negative space, which is photographed in the camera, but not projected) | | | | |O -------------------O| |O (unused space) O| | | | | | ------------------- | |O | Image |O| |O | Image |O| | | | | | | Area | | |O | Area |O| |O | |O| | | | | | ------------------- | |O -------------------O| |O (unused space) O| | | | | |<-------- 35mm -------->| |<-------- 35mm -------->| super 35mm/silent film frame: 35mm anamorphic film frame: | | | | |O----------------------O| |O -------------------O| | | | | | | | | |O| Larger |O| |O | 'Squeezed' |O| | | Image | | | | Image | | |O| Area |O| |O | Area |O| | | | | | | | | |O----------------------O| |O -------------------O| | | | | |<-------- 35mm -------->| |<-------- 35mm -------->|
Vista Vision film frame:
-------------------------- ---
O O O O O O
O O /|\
|--------------------|
|
| Very Large
| |
|
| 35mm
| Image Area
| |
|--------------------|
|
O O O O O O
O O \|/
-------------------------- ---
NOTE: The blank space to the left of the image area in the above diagrams (except for Vista Vision and super 35mm) is reserved for a soundtrack which is printed on release prints.
It is hoped that the new digital sound formats will eliminate the magnetic striping used in the past for soundtracks, which contributed greatly to the cost of this format. Also, the potential exhibition market for this format is larger than it has been in the past, since many of the recently-built multiplex theaters have at least one screen which is capable of showing 70mm, which was often originally installed in order to show blowup prints of 35mm with the six-track stereo sound which only the 70m print could provide (prior to the advent of digital). The DTS digital format was successfully used for the 1996 70mm restoration prints of Vertigo (photographed in VistaVision). In 1997, several 70mm blowup prints of Titanic were struck from the super 35mm negative, also employing the DTS system.
There is a similar process to IMAX (tm) , known as IMAX-HD (tm) , which uses the same setup, running at 48 frames per second, in order to achieve a more life-like, better-looking picture.
It is worth noting that none of the formats yet designed by the Canadian IMAX (tm) company carries a soundtrack on the print. In older setups, the sound is reproduced from a 35mm 6-track magnetic film which is run on a dubber-type device, interlocked to the speed of the projector (and if the power fluctuates significantly during a show, sync is lost). Newer installations also have the capability of running the sound off of a CD-ROM disk (as with DTS (tm) ), driven by a tachometer output from the projector or a timecode on the film; even when the sound is reproduced from CD, magnetic film is often still run as a backup. A few films (such as Grand Canyon) used soundtracks reproduced from 1/2" audio tape, using an 8-track recorder synched to the projector.
regular 8mm release print frame: super 8mm release print frame: (note big perforations) (note small perforation) | | | | |s-------------- O | |s---------------- | |o| Small | | | |o| Larger | | |u| Image | | | |u| Image |o| <--- Smaller |n| Area | | | |n| Area | | Perforation |d-------------- O | |d---------------- | | | | | |<------ 8mm ----->| |<------ 8mm ----->|
Unlike camera films, 16mm release prints are almost always single- perforated-i.e. the film has perforations on only one side of the image. The other side is reserved for a soundtrack. The only exception to this are lab workprints from double-perf camera stock, which are also printed on double-perf stock, mostly for convenience in splicing with a `guillotine'-style tape splicer, commonly used by editors.
16mm release print frame: | | |sO--------------O | |o| Image | | |u| Area | | |nO--------------O | |d | |<----- 16mm ----->|
There are several commonly used formats which use this principle, of which the most common currently is the U.S. standard of aspect ratio 1.85:1, used on almost all `flat' prints currently in circulation. One of the major disadvantages of this format, however, is its terrific inefficiency of negative space. Although the camera and projector both move the film four perforations at a time (the height of the Academy frame), the actual projected image only takes up 2.5 frames. Thus, images are grainier and less sharp than those of Academy films projected on the same height screen.
The proposed 2.5-perf and 3-perf formats (described elsewhere in this FAQ) do not change the area of the 1.85:1 frame, but simply move the film a shorter distance (2.5 or 3, rather than 4 perforations) between frames, using less film per unit of running time. As proposed now, these are strictly release-print formats; 35mm cameras will continue to move the film 4 perforations per frame (although 3-perf is gaining acceptance as an cheaper alternative for TV work).
A few films made in the 1950's were made to be projected in the 1.75:1 aspect ratio; while this is no longer a common projection ratio, it is interesting now, because it corresponds very closely to the 1.77:1 proposed U.S. High Definition Television (HDTV) standard, designed as a compromise in order to fit both 1.37:1 television material and wide screen feature films onto the same size screen.
The standard frame ratio in Europe is still 1.66:1, the same as the super 16mm standard. These films are almost never shown properly in the U.S., however; most are simply cropped to fit onto screens masked for 1.85:1.
The first CinemaScope (tm) (anamorphic) feature was The Robe, released by Fox in 1953. These prints were made with tiny `Fox hole' perforations, and contained four tracks of magnetic sound (quite impressive, particularly in a time when most movie-goers had not even heard regular stereo!). Due to the narrow perforations, an aspect ratio of 2.55:1 was achieved for early Cinemascope (tm) pictures, including The Robe, the first Cinemascope (tm) production.
In 1956, the 'scope ratio was narrowed to 2.35:1 in order to accommodate both magnetic and optical tracks on the same print (so that it could be shown in theaters not yet equipped with magnetic sound equipment). This ratio was retained until 1971, when the height was reduced slightly, resulting in a 2.39:1 aspect ratio, in order to better hide lab splices.
In 1994, the height and width were reduced proportionally, retaining the 2.39:1 aspect ratio, which is the current standard.
---------------------------------------- c) | | | | | | | | (c u) | | | | | | | | (u r) | | | | Movie | | | | (r t) | | | | Screen | | | | (t a) | | | | | | | | (a i) | | | | | | | | (i n) ---------------------------------------- (n ^ ^ ^ ^ ^ ^ ^ ^ | | | |----- 1.37:1 -----| | | | | | |-------- 1.66:1 --------| | | | |------------ 1.85:1 ------------| | |----------------2.39:1 ---------------|It should be noted that having separate lenses and masks for each format is highly idealistic, and is not standard practice, except at a few conscientious art houses, which must show prints from all time periods and all countries. Most U.S. theaters are only equipped to properly show 1.85 and 2.39:1 ratios, lacking the appropriate lenses/masks and ability to move the curtains to other ratios. Thus, when prints intended for other formats are shown, some of the image is usually cropped. Some theaters show everything at 2:1 (eliminating the need for changing the screen masking), cropping some from all formats. In any event, there is a wide degree of variance in image cropping, depending upon the equipment in place in each venue.
35mm release print frame: (1.85:1 ratio) (usually, picture is visible above and below 1.85:1 framelines, but it is 35mm release print frame: masked off, and does not show up on (Academy ratio) the screen) | | | | |O -------------------O| |O (unused space) O| | s | | | | s ------------------- | |O o | Image |O| |O o | Image |O| | u | | | | u | Area | | |O n | Area |O| |O n | |O| | d | | | | d ------------------- | |O -------------------O| |O (unused space) O| | | | | |<-------- 35mm -------->| |<-------- 35mm -------->|
Much of the expense of making 70mm prints in the past has been the magnetic striping which is necessary for the soundtrack, as there is no such thing as 70mm optical sound. With the possibility of printing a DTS (tm) timecode on the 70mm print, and providing the actual soundtrack on DTS (tm) CD-ROM disks (like with 35mm DTS (tm) ), this may no longer be necessary, possibly paving the way for a 70mm revival. This remains to be seen, however, although it was done successfully for the 70mm release of Hitchcock's Vertigo in October, 1996; the prints had no analog tracks and entire soundtrack was reproduced from a DTS (tm) disk (most theaters used two disk readers with identical disks in them for redundancy), driven by DTS (tm) timecode printed on the outside edge of the perforations on the left-hand side (relative to how the film runs in the projector) of the image.
In addition to the conventional sprocket holes, all 70mm prints also have a small `registration hole' punched every 5 perforations. Theoretically, this is supposed to line up with the frameline, but, in practice, this is ignored, and it just occurs at a random point. The primary purpose served by the registration hole is for use as a splicing reference, so that splices can always be made at the frameline, even in the middle of a fadeout or a dark scene.
70mm standard release print frame:
(courtesy David Richards \texttt{daverich@netcom.com})
|XXoX|____________________________________|XoXX|
|XX X| |X XX| 'o' = sprocket hole
|XXoX| |XoXX|
|XX X| |X XX| 'X' = mag. track area
|XXoX| |XoXX|
|XX X| |X XX| (registration hole not
|XXoX| |XoXX| shown in this diagram)
|XX X| |X XX|
|XXoX|____________________________________|XoXX|
|XX X| |X XX|
|<---------------- 69.95mm ------------------->|
|<---------------- 2.754in ------------------->|
The primary disadvantage to this system of recording sound in the camera is that it makes good editing extremely difficult. Super 8mm is usually shot with reversal film (see below), meaning that the camera original is edited and then projected. In this case, after every splice, there will be a delay of about one second between when the picture edit shows up on the screen, and when the sound edit is heard; this is a result of the sync offset of the soundtrack. For this reason, professional films (except old television news films) almost never record sound within the camera, but rather use a `double-system' method, in which the sound and picture are kept on separate strips of film through the editing process, until the final release prints are made. Home movies, though, rarely undergo substantial editing; thus, `single-system' sound recorded in camera is useful and convenient.
Sound quality is not particularly good, but has been improved in recent years by various methods, including the printing of two identical tracks which are adjacent to each other. This method allows the two tracks to cancel out each other's flaws or at least to cover them up (in theory). Whether or not this actually improves sounds quality is a topic of debate. Thus, Although it is technically possible to produce a stereo optical track in 16mm, no one has yet exploited this potential on a wide-scale basis, as there is no commonly available equipment to shoot a stereo track, or to reproduce it. A few test prints were made in this format, however.
By now (1998), 16mm magnetic is almost a dead format for new prints, having been replaced with 35mm blowups of 16mm-originated material or by double-system digital systems (usually with a DAT machine synched to the movie projector).
Eventually, in the 1970's, the standard monophonic track was modified to permit stereo reproduction. This allowed optical tracks to offer competition to the four-track magnetic systems in use at the time. The reproduction of stereo tracks required modification of the projector's soundhead to accept a stereo solar cell. The optical stereo approach was not used commercially, however, due to background noise and hiss issues. In the mid-1970's, Dolby (tm) Laboratories developed methods of `matrixing' the SVA (stereo variable area) track in order to encode four tracks worth of information within the twin stereo tracks. This allowed for the additions of a center (dialogue) track and a rear `surround' track to the usual left and right stereo tracks. In addition, Dolby (tm) type `A' noise reduction was used to reduce background noise.
This `Dolby Stereo (tm) ' system soon became standard, and nearly all commercially released films since about 1980 have been encoded with it. Of course, one must use a Dolby (tm) Cinema Processor (or a clone thereof [e.g. `Ultra Stereo']) in order to decode and reproduce all four tracks; otherwise, it just reproduces as two-track stereo. `DTS Stereo (tm) ' uses the same principles as Dolby Stereo (tm) and is decoded with the same equipment, but the term applies to optical tracks produced by DTS (tm) , without the use of Dolby (tm) equipment (Dolby (tm) encoding equipment is usually rented out for higher rates). Note that `DTS Stereo (tm) ' is distinct from the DTS (tm) digital sound system described below.
In the late 1980's Dolby Stereo (tm) was improved upon by `Dolby SR (tm) .' The `SR' stands for `spectral recording,' which incorporated better channel separation and noise reduction than standard Dolby Stereo (tm) , but which supposedly retained compatibility with Dolby (tm) type `A' processors, although this is debatable. A Dolby (tm) `A' processor can be upgraded to support SR prints, if desired. Type `A' prints do not reproduce well when played back through a processor set up for `SR' mode (all modern processors also contain the `A' NR mode as well).
Incidentally, Dolby (tm) `A' noise reduction is one of several noise reduction schemes developed by Dolby (tm) Laboratories. It (and SR) are capable of reducing noise across the entire audible frequency range. Dolby (tm) also developed type `B' noise reduction, which reduces the high- frequency noise common to audio cassette tapes, and type `C' noise reduction which is also used for cassettes, as well as the Beta SP videotape format.
This idea worked reasonably well, and was used for a number of years (through the early 1970's) on 35mm prints of all formats (only 'scope prints required the Fox holes, though), and the sound quality was excellent, even by today's standards, provided that the magnetic tracks were in good condition. The problem of this scheme was that, unlike optical sound, the information recorded on magnetic tracks was not a permanent part of the film, and could be intentionally or accidentally erased, simply by being placed too close to magnetic fields, like those found in electric motors (such as those used on rewind benches). Even reels and cans can become magnetized, sometimes erasing all or part of the magnetic track, requiring that it be re-dubbed, at great expense. Further, the magnetic sound heads required frequent cleaning in order to keep them sounding good.
With the invention of Dolby (tm) `A' noise reduction and the application of this technology to optical tracks, magnetic sound lost some of its quality advantage over optical, and it has always been substantially more expensive than optical to print (as prints had to be dubbed in real time, whereas optical could be printed at the same time and speed as the picture). Thus, magnetic sound fell into disuse, and is no longer commonly used, although, before digital sound became workable, special prints were made with magnetic tracks for showing in select theaters for `special engagements' and the like.
As mentioned above, in the late 1970's (beginning with Star Wars) through the late 1980's, it was common for distributors to produce 70mm blowup prints of films shot on 35mm in order to improve sound reproduction in the movie theater. With the introduction of digital systems, which are capable of reproducing higher quality sound at a lower cost than a complete 70mm projection system and 70mm print rental, exhibitors no longer saw much reason to show blowup prints, except for special `one-time' shows. In the future, magnetic striping (a major cost of making 70mm prints) may be eliminated, in favor of a digital soundtrack (currently, DTS (tm) has been used for 70mm prints). This may encourage the printing (and 65mm original cinematography) of more films for 70mm exhibition.
Unlike other formats, where the soundtrack runs ahead of the picture, with 70mm, the sound runs behind the picture, as the magnetic sound heads are placed before the picture head. Thus, the 70mm print runs through the magnetic soundhead, picture head, then around the 35mm optical soundhead, then to the takeup reel or platter. When 35mm films are run in a combination projector, they are simply loaded through the 70mm magnetic soundhead, without difficulty.
Despite the differences among the various digital sound formats, most people cannot tell a difference in quality, as they all sound excellent. Perceived differences among the formats are usually a result of a different sound mix for each format (such as an 8-channel SDDS (tm) mix versus a six-channel Dolby (tm) Digital mix).
DTS (tm) uses a timecode printed on the film between the picture area and the optical track. The timecode, which looks like a dot-dash pattern (resembling Morse code) is read by an optical reader placed in the film path, between the platter or reel and the projector's picture head. This timecode information is fed to a specialized, souped-up 386 or 486 computer which in turn reads compressed soundtracks from a CD-ROM disk; the compression factor, though, is the least of the three digital systems. The current systems have three separate CD-ROM drives: one holds a `trailer' disk which is sent to theaters periodically, and contains the soundtracks to all of the trailers currently showing, including trailers from studios which do not use DTS (tm) for their films; the other two contain disks for the feature. Shorter movies require only one disk; others require two. Slightly over four hours of digital sound can be accommodated for a two-disk feature. There is no provision for mid-show disk changes.
As with all digital sound systems, the film reader can be placed a variable number of frames ahead of the picture head. This is calibrated upon installation with a test film. The computer is capable of accommodating splices within the film, and adjusting the soundtrack to match. Further, because the soundtrack is not on the film, no `popping' noise is heard during splices and/or changeovers (unless the timecode reader cannot read a certain section of timecode, in which case it reverts back to the standard analog track).
As with all of the current 35mm digital systems, all prints (except 70mm DTS prints) contain a standard optical track (usually recorded in `DTS Stereo (tm) ,' a system which is compatible with Dolby (tm) -type processors) as a backup, should the timecode not be found, or be unreadable for more than 40 frames. The analog track is also used when the CD-ROM disk does not match with the movie being shown (at least in theory-there have been reports of theaters' showing one movie with another's soundtrack).
In SDDS (tm) , the sound is actually recorded on the film itself, along both edges of the print. SDDS (tm) uses a middle level of compression of the digital information of the three current digital systems. Like the other digital systems (except for Dolby), the reader (which uses an LED to shine through the track) is placed somewhere in the film path prior to the film's entrance into the picture head (the offset is variable, as convenience dictates, and is set up at installation). The reader reads the track, which is then decoded, decompressed, and processed in a separate processor unit, which contains custom electronics designed for this purpose. Just as with analog sound, splices are accommodated without difficulty.
SDDS (tm) is probably the most expensive of the three digital formats, although actual cost varies substantially among different theaters and chains. The expense is largely due to the fact that all of the electronics within the entire processing system are digital, whereas DTS (tm) and Dolby (tm) Digital are both designed to simply be plugged into existing analog Dolby (tm) (or similar) cinema processors. However, the extra cost may be somewhat justified by the extra tracks and the fact that the marketer of this system also owns companies which produce many films each year, almost ensuring that there will be material in this format for many years to come.
Although it is expensive, SDDS (tm) is very popular, particularly in the AMC, Sony, and United Artists theaters, where SDDS (tm) is or will be used in most of the theaters. Many technicians like it because it is the only system with electronic equalization, allowing the system to be properly set up very quickly.
The actual digital sound information is printed on the film in between the perforations, generally considered to be a safer location for the sound information than the edge of the film (where SDDS's (tm) track lives). Thus, Dolby (tm) Digital is potentially more reliable than SDDS (tm) , although it compresses the digital information to a lesser extent than SDDS (tm) does. Like SDDS (tm) , the track is read, and then decoded, decompressed, and processed by a separate unit. Splices can create small `pops,' (and will revert to analog if more than five perforations are obscured, but this is unlikely..
This format appears to be increasing in popularity at this time, both in terms of the number of theaters installing the system and the number of prints available in that format. It is also considered to be slightly more reliable than the other two digital formats, as the sound is printed directly onto the film in a relatively `protected' location. All prints still contain an analog optical track (usually recorded in Dolby (tm) SR), in case the digital system fails, or is unable to read five consecutive `blocks' (between perforations).
Technically, it is possible to, with minimal cost, print all three types of digital track (or, in the case of DTS (tm) , timecode), along with analog optical Dolby (tm) on a single print, and a few films have been printed this way. These multi-format prints are now quite common (containing at least two formats), especially on movie trailers. Similarly, it is possible to have a projection system which can accommodate all of these formats, without excessive difficulty.
As mentioned in the 70mm section, DTS (tm) timecode has been printed on 70mm prints (most notably the 1996 restoration prints of Vertigo), and used to drive a DTS (tm) CD-ROM disk, from which sound was reproduced as with the 35mm implemetation of DTS (tm) . A standard DTS (tm) setup is required for this type of system, as well as 70mm timecode readers (which are swapped in for the 35mm variety as needed), and, often, a second DTS (tm) CD unit, which holds a duplicate set of CDs and provides a backup should the first unit fail.
As of February, 1998, there is no indication as to whether Dolby (tm) or Sony (tm) were planning to adapt their 35mm digital systems for use with 70mm.
Larger theaters built from the 1960's through the 1980's may instead be using combination 35/70mm projectors, like the Norelco AA-II (known in Europe as the Philips DP-70), and Century JJ, although, with the decreased availability of 70mm features of late, most of these machines are either used exclusively for 35mm shows or are sitting idle.
Most modern theaters use xenon bulb lamphouses of between 2 and 4 kilowatts. This provides a picture of adequate brightness on the medium-sized screen common in multi-screen cinemas. A larger lamphouse of up to 5-7 kilowatts is needed for a very large screen, such as that of a drive-in theater; larger lamphouses offer little increased benefit for 35mm. Older theaters often still use carbon-arc lamps, which require more attention on the part of the projectionist than xenon, but some feel that they offer a light of better color temperature (i.e. not as cold-looking) than xenon. The general rule of thumb for xenon lamphouse size is roughly 1kw of power for every ten feet of screen width; thus a 30-foot screen should require about a 3kw lamphouse.
As for the film handling system itself, automated cinemas usually use film `platters,' in which the entire print is loaded onto a large plate-like device (with the film from the individual shipping reels spliced together into one continuous roll), permitting one projectionist to operate the projection equipment for many auditoria. Smaller theaters and older theaters often use two projectors with small reels, each holding either 2000' each (just like the shipping reels) or 4000-6000' each (with the contents of two or three shipping reels spliced together). Between the reels, the projectionist operates a changeover mechanism, simultaneously switching over machines and soundtracks. He then rewinds the next reel, reloads it on the idle projector and prepares for the next changeover.
Typical Multi-Track Dolby (tm) Stereo/Dolby (tm) Digital/DTS setup: (This is the same setup used for Dolby (tm) Stereo, DTS (tm) , and Dolby (tm) Digital setups, although the digital systems have separate L and R surround channels, as well as a channel for a subwoofer [which is located behind the screen]. Complete SDDS systems and 70mm also have Left Center [LC] and Right Center [RC] loudspeakers, not indicated here)
Left Stereo (L) -- behind left side of screen Right Stereo (R) -- behind right side of screen Center/Dialogue (C) -- behind center of screen Surround (S) -- in rear of auditorium (separate L/R in digital) Subwoofer (sub) -- behind screen (separate channel for digital)
/----------------------------------------------------------\ | * L * * C * * R * | | * spkr * (sub) * spkr * * spkr * | | ------------------- screen ------------------- | | | | (front of auditorium) | | | | UUUUUUU UUUUUUUUUUUUUUUUUUUUUUUU UUUUUUU | | UUUUUUU UUUUUUU audience UUUUUUU UUUUUUU | | UUUUUUU UUUUU seating area UUUUU UUUUUUU | | UUUUUUU UUUUUUUUUUUUUUUUUUUUUUUU UUUUUUU | | UUUUUUU UUUUUUUUUUUUUUUUUUUUUUUU UUUUUUU | \ \ / / \ \ |* S * UUUUUUU UUUUUUUUUUUUUUUUUUUUUUUU UUUUUUU * S *| |*spkr* UUUUUUU UUUUUUUUUUUUUUUUUUUUUUUU UUUUUUU *spkr*| | UUUUUUU UUUUUUUUUUUUUUUUUUUUUUUU UUUUUUU | | UUUUUUU UUUUUUUUUUUUUUUUUUUUUUUU UUUUUUU | |* S * UUUUUUU UUUUUUUUUUUUUUUUUUUUUUUU UUUUUUU * S *| |*spkr* *spkr*| | * S * * S * | | *spkr* (rear of auditorium) *spkr* | \----------------------------------------------------------/Digital sound systems use similar loudspeaker arrangements as Dolby Stereo (tm) setups, possibly with additional loudspeakers to support SDDS (tm) eight-channel mixes. The sound is read by specialized readers placed between the reels/platters and the projector head; this contrasts with the placement of the analog soundhead, which is located between the projector head and the take-up reel/platter.
Older installations may use or have once used carbon-arc lamphouses; in these setups, high electrical current is passed between two carbon rods (one positive and one negative), creating an electrical arc and a very bright flame in the gap between the two rods. In order to operate such a lamphouse, the projectionist inserts the rods into their steel holders, closes the lamphouse, switches on the power, and, watching through a shielded piece of glass, carefully brings the rods together (using positioning knobs on the side of the lamphouse), causing them to touch. At this point, the arc will strike, and he can bring the rods apart and allow the current to stabilize. As the carbon burns down during the show, a motor brings the rods together, maintaining a constant distance between the tips of the rods, which must be tweaked by the projectionist as the show goes on, in order to maintian consistant on-screen light. Every 30 minutes to an hour of use, the rods will burn down and must be replaced.
Separate rods are used for `positive' and `negative' poles; a longer, thinner one is placed in the positive holder, and a shorter, fatter one is used for the negative holder. These designations should be marked on the box of carbon rods. Fumes from carbon-arc lamphouses are highly noxious, and should be well ventilated.
Note that both xenon and carbon-arc lamphouses require DC power, provided either by DC mains or by a rectifier circuit (which converts standard AC power to DC). Older theaters may use motor-generator sets to generate DC power.
At some undetermined time, new prints are likely to be shipped on the so-called Extended Length Reel (ELR), which is capable of holding 6800' of standard triacetate film or 8000' of the thinner polyester stock. Trials of this began in Summer 1997, with prints of Addicted to Love and Batman and Robin. These prints were also available on 2000' reels for theaters which requested them. This is expected to reduce the amount of time needed to build up a print on platters, and possibly reduce the damage done in the buildup/breakdown process. This standard is supported primarily by the exhibitors (who will save in labor costs) and film laboratories (although some will need to buy new equipment to handle the larger reel sizes). Presumably, at least for a certain amount of time, 2000' reel sizes will also be distributed for these films, in order to accommodate theaters which do not have platters or 6000' reel arms, and must instead run the films with 2000' reels. Eventually, these houses may have to convert to 6000' changeover or platters or cut up the ELR prints themselves.
It should be noted, also, that nitrate prints have sometimes been shipped on 1000' reels, due to fire-hazard concerns. This configuration presents less of a danger, should one reel catch fire, as there is less film to burn. These nitrate films also are usually stored on metal shelving, in asbestos-insulated fire-proof rooms. Modern triacetate or polyester films, of course, do not require these precautions.
When the film arrives at a changeover house, the head projectionist rewinds the film onto cast-iron house reels, inspecting the print for damage and splices, as well as (hopefully) ensuring that the changeover cue marks are properly positioned: 4 frames "motor" cue, then 10 ft. 8 frames, then 4 frames "changeover cue" then 20 more frames.
The second reel has, hopefully been loaded up properly in the second machine, with the framelines lined up with the top and bottom edges of the gate (if this is not done, the film will probably appear out of frame, and the projectionist will have to manually adjust the projector's `framing' knob in order to position the picture correctly on the screen. Two types of leader are currently found on release prints. New SMPTE Universal Leader is marked off in seconds of time (considered to be more useful for television stations), and counts down from `8' to `2'. This is used on nearly all new prints. Older Academy Leader is marked off in feet of film, counting from `11' to `3,' and is common on older prints. The projectionist simply remembers which frame of each type of leader needs to be loaded into the projector in order to give the correct `run-up' time between cue marks. If the leader is not complete and the projectionist is not able or willing to replace it, he must wait after the first cue mark (before starting the motor on the second machine) until roughly where the next reel was loaded.
Once the second projector is going, the projectionist waits for a second dot, located 20 frames from the end of the first reel. Within a half-second or so after seeing this, he hits another button, which switches over the soundtrack, and simultaneously opens (on the machine holding the second reel) and closes (on the machine holding the first reel) a metal `changeover' blade, which allows the passage of light through the film and, of course, onto the screen. The first reel is either stored in the film's metal shipping case, or rewound back onto a house reel on a rewind bench. The process is repeated for every reel change.
So-called `endless loop platters' also exist, and work similarly, although they omit the donut, and instead require that the head and tail be spliced together, allowing the same film to be run multiple times with no interruptions. Unfortunately, though, these systems discourage the cleaning of the projector gate, and, as dust and dirt accumulate there (an inevitable result of showing films), can lead to print scratches and other damage.
After building up a print on a platter, it is good practice for the projectionist to run it once in order to preview the print for any problems which may have been introduced in print buildup (like bad splices) and other defects, which may have been introduced elsewhere (like deep scratches, or lousy lab work). Splices used to build up prints on platters are usually made with `zebra' tape, which has yellow markings which help the projectionist to locate the splices when breaking down the print onto the shipping reels.
This is occasionally done in multiple-screen theaters; the projectors which are going to be interlocked need to be adjacent to each other (or at least reasonably close), and must be fitted with synchronous motors, whose speed is controlled by the 60hz (in the U.S.; 50hz in many other countries) AC line frequency. The film is loaded from a platter through the first projector (as usual), and then passes over several rollers, mounted on a wall or ceiling, across the booth to the second projector, into which it is then also loaded normally. Somewhere between the two machines, there is usually a bit of slack in the film, where a weighted roller is placed in order to keep the film running smoothly if there happens to be a small speed variation during the show.
Both projectors must be started at exactly the same time in order to maintain the proper amount of slack between them. This is done either by two projectionists, or by an automation system capable of handling this function.
It should be noted that the term `interlocked' is also commonly used in the context of a sound mix facility, where several magnetic dubbers, and, usually, a projector, must be mechanically or electronically interlocked together in order to ensure that the multiple soundtracks being mixed are in perfect sync with each other and with the workprint being projected.
These comments apply to the Century projector. There are two significant differences between a 35/70 projector and a standard 35mm projector. First of all, it must acommodate two gauges (widths) of film. This mainly impacts the gate. Typically, the gate is easily removable. Whereas the 35mm projector is restricted to accepting a 35mm gate, the 35/70 projector comes with two gates, one for each gauge of film. These gates are precision machined to slide onto dovetails on the frame, and should not be interchanged between projectors. The gates are stamped with the frame serial number to prevent mix-ups.
The second difference is the frame pitch. Standard frame pitch for 35mm film is 4 perforations, or .748". 70mm film uses the same perforation pitch, but 5 perfs per frame, or .935". Both must advance at 24 frames per sec. There are two possible ways to accomodate the faster linear speed of 70mm. One would be to simply turn the sprockets faster, with gearing for example. But this would not work with the existing geneva movement, and would also throw the shutter timing off. The way it is actually ac- complished is by using dual sprockets. There are 3 critical sprockets: the upper feed sprocket, which pulls film off the reel or platter at a constant speed, the intermittent sprocket, which advances the film at the gate, and the lower sprocket, which smooths out the pulsations from the intermittent sprocket once again. There are additional sprockets in the area of the sound head, but they do not need to be used for 70mm, as there is a separate magnetic sound reader for that.
Typically, these sprockets have 16 teeth for 35mm film. Since one frame is 4 perfs, exactly 4 frames could be wrapped around each sprocket. Another way of saying this is that each sprocket turns 90 degrees per frame. Since 70mm film requires a 5-perf advance, we can simply increase the number of sprocket teeth by 5/4, to 20 teeth, and the speed and intermittent advance distance are increased exactly the right amount, without changing the Geneva movement, motor, or anything else. By a happy coincidence, the 70mm film requires both a larger diameter sprocket, and one with the two sets of teeth further apart to accommodate the greater width. So, by using stepped sprockets, both may co-reside on the same shaft. The 35mm film rides in-between the larger 70mm sprocket flanges.
The only thing remaining is the pads that hold the film against the sprocket. Since there are two different sprocket diameters, there are two different places the pads must stop. This is accomplished on the Century with two different diameter pad rollers, which rotate individually, the assembly of both of them revolves on a common shaft with a knob. By turning the knob one way, the 35mm pad roller comes against the film. By turning the knob the other way, the 70mm pad roller comes against the film. With 35mm film threaded on the machine, turning the knob the wrong way does no damage, however, the film will not be held securely against the sprocket. With 70mm film threaded, care must be taken, because turning the knob the wrong way will damage the print.
This combination 35/70 idea, while good in theory, has some drawbacks in practice. Even with everything set correctly for 70mm, it is sometimes possible for the base side of the film to touch the 35mm pad rollers. This can cause base side scratches, which show up as dark lines about 1/4 of the picture width from each side. Those "in the know" will remove the 35mm pad rollers when showing a 70mm print, and replace them with spare 70mm rollers. This allows them to turn the knob either way without creasing the print, and at the same time eliminates the risk of base-side scratches.
As a footnote, the lamphouse generally must be readjusted for 70mm as well, to cover the larger frame area.
The severity of this and other problems varies substantially among films manufactured by different companies. Further, the resistance to breakage is the primary reason why polyester is not used on camera films, as the risk of damage is much greater when the film is run through expensive camera equipment. (Polyester camera film is manufactured and used for high-speed cameras used to capture slow-motion images for scientific and engineering work, as the mechanisms of these cameras run so quickly that they would be severely damaged if the film were to break while the camera was running).
Polyester stock is also thinner and lighter than acetate stock (one can identify it as polyester by holding a reel up to a light source in a sideways position (such that it appears round from the viewer's point of view); if one can see light through it, then it is polyester). This can reduce the number of shipping reels, and the shipping cost, but may require adjustment of gate pressure in the projector in order for the film to run properly. Also, the stock is more sensitive to low humidity than triacetate, as it tends to pick up static electrical charge, sometimes preventing it from running smoothly on a platter system. The most often recommended solution to this ailment is to ensure that the platters are properly grounded, and that a humidifier is present in the projection booth. This will also help to avert unnecessary dust accumulation on the print.
The texture of polyester stock is substantially different from that of triacetate stock, and cement splices are not useful on polyester films (either tape or ultrasonic splices must be used). Thus, projectionists usually use the more-visible tape splices to join film together.
The static and strength problems were particularly acute with many prints of American President, one of the first major features to have 35mm prints distributed on polyester stock. Commonly, when run on platters, the film layers would `stick' together, jamming the feed mechanism, and, usually, causing the whole projector to stop (by means of `failsafe' assemblies which stop the motor when there is excessive tension on the guide rollers).
It should also be noted that the IMAX (tm) format requires that polyester-based film be used, due to the relatively high linear speed at which the film moves through the projector (about three times that of 35mm), and the potential damage to the projector should there be a film break in the middle of a show. However, IMAX (tm) equipment was designed for polyester film, and has several safeguards not present in most 35mm projection equipment in order to avert potential disasters in the projection booth.
Perhaps the most important task prior to running a nitrate print is to determine whether it is permitted by local laws to do so. Many com- munities have outlawed the projection or storage of nitrate film material due to the grave safety concerns associated with its use. Assuming that projection of this film is legal in the local area, and that the booth in question meets all necessary specifications (metal plates which can be dropped down to cover portholes in case of accident, fireproof construction, metal door, outside ventilation, etc.), then one would most likely want to snip off a piece of head or tail leader of the film and ignite it in order to determine its flammability, as this varies widely as film goes through various stages of decomposition. The print should be thoroughly inspected to ensure that it is not damaged in such a way that it may jam in the gate and ignite (more likely if the print has shrunk significantly or has lousy splices). The print should then be run in an attended booth off of 2000' or 1000' reels, and certainly on a platter or on large reels, in order to minimize the outcome of any possible disaster. In between shows, the reels should be stored in metal containers away from high heat sources.
A more thorough inspection would involve running the film through a sync block to ensure that no out-of-frame splices had been made, as well as possibly running the film through some type of cleaning device in order to remove any dust or dirt which may have accumulated on the print.
------------------------------------------------------------------ 'A roll' | <----scene 1----> | <----black leader----> | <----scene 3----> | ------------------------------------------------------------------ ------------------------------------------------------------------ 'B roll' | <--black leader-> | <-------scene 2------> | <--black leader-> | ------------------------------------------------------------------The print film is then run through the printer (at the lab.) thrice, first exposing it to the `A roll,' then rewinding, then exposing it to the `B roll,' then rewinding, then exposing it to the soundtrack. The completed print (if printed properly) contains all scenes in order without visible splices in between, as well as an in-sync soundtrack. If white titles are needed, then the print film is run through again, this time being exposed to a `C roll,' containing main or subtitles. Fades and dissolves (cross-fades between scenes) are made at this time too, using either a punched paper tape or notches in the edges of the negatives as cues.
This A & B roll method is not always necessary for 35mm, as enough of the area around the frameline is masked off in projection to permit splicing the film negatives into a single strand which can be printed in one pass through the printer, instead of two. The A & B rolls are necessary, though, for dissolves between scenes, and for superimposed images.
When working with black-and-white films, only one set of points is used, as there is no color balance to worry about. In this case, the `timer' simply manipulates the exposure of the image. Incidentally, the term `timer' comes from the days before automated printers when the `timer' actually had to determine how long certain portions of the print should be allowed to sit in the developer. Of course, this is no longer necessary, and all print films are processed in the same manner.
Each scene is timed, and the printer's points for each scene are encoded onto a punched paper tape (or, in older arrangements, as notches in the edges of the negatives to indicate the changes, which would be manually set by the printer operator, just like fades/dissolves). The printer then reads these cues and electronically adjusts its lights and filtration to match the cues. Other methods for cuing the timing changes have been employed, although the paper tape appears to be the most common at this time.
Note that prints made from internegatives must be run through the printer only once, as the internegative contains all of the elements (A/B/C rolls, optical track) necessary for the print, whereas original- negative prints must be run through the printer at least three times. Thus, prints made from internegatives are about 1/3 less expensive than original- negative prints.
There is not much that has been written on this subject in years, so the following suggestions are based only on my personal experimentation. If anyone who has experience with this sort of thing would care to make suggestions on how I could improve or refine this process, or would like to ask any questions, feel free to e-mail me.
HOME B&W MOVIE/SLIDE PROCESSING:
The only home movie processing tank still sold that I am aware of is
the G-3 Daylight Processor sold by Doran Enterprises in Milwaukee, Wisconsin,
USA. Their phone number, if you wish to order one is 414-645-0109.
The tank is not ideal--the good news is that it only takes one liter (or one quart) to process up to 200 ft. of Super 8 or 16mm film (or about 1.5 liters for 35mm film). The bad news is that it is kind of tedious to use.
Since it is a "rewind" tank, the operator must continuously wind the film back and forth from one reel to another. At recommended winding speed of 2 turns per second, a complete wind of one 50-ft. Super 8 film would be about 45 seconds from one end to another. For 100-ft spool of 16mm (or two Super 8 films stapled together) the time would be one minute. At 200 ft., time would be 90 seconds.
IMPORTANT:
1. Emulsion should be face out.
2. Unless Prebath PB-3 is used when film is first submerged, tilt the
tank and pour in enough water so that the reel with no film is wet and
reel with film is dry. Then wind dry film onto wet reel so that emulsion
is uniformly made wet.
PROCESSING STEPS:
I do not have recommendations for developing Ektachrome film but for
developing B&W films like Tri-X Reversal 7278 or Plus-X Reversal 7276,
use the following processing steps:
SOLUTION and suggested NUMBER OF WINDS AT 68F (20C):
FIRST DEVELOPER: 12 (Or 8 at 80F--This is the most critical step. Decrease
number if fully processed films are consistently too light; increase if
too dark.)
RINSE: 4 (change water each time)
BLEACH: 10 (8 at 80F)
CLEARING BATH: 8 (6 at 80F)
Now remove cover of tank, add water, and re-expose film under a bright 200 to 500 watt light or in sunlight for two to three complete winds. Cover tank and continue:
SECOND DEVELOPER: 8 (6 at 80F)
You may now rinse film (5 winds running water) and dry, OR if you want to harden emulsion and make film less prone to scratches (recommended if the film is expectd to have heavy usage) add the following steps:
RAPID FIXER: 2
RINSE: 2
HYPO CLEARING AGENT: 2
RINSE: 5 (running water)
PHOTO-FLO (optional):2
To dry film, string a line across the room and loop film over and over the line, emulsion side up, for uniform drying. Spool onto projector reel emulsion side out.
SUGGESTED SOLUTION FORMULAS:
FIRST DEVELOPER: Add 9.5 grams of sodium thiosulfate to 1 liter of Kodak D-19 developer regular strength.
BLEACH: To one liter of water add 9.5 grams of Potassium Dichromate and 12 ml of concentrated Sulfuric Acid.
CLEARING BATH: To one liter of water add 90 grams of Sodium Sulfite.
SECOND DEVELOPER: Use standard paper developer like Dektol or Polymax T regular strength.
FIXER: Use Kodak Rapid Fixer or similar.
HYPO CLEARING AGENT: Use Kodak Hypo Clearing Agent, or similar.
PHOTO-FLO: Use Kodak Photo-Flo or similar.
These solutions can also be used to make B&W slides from almost any 35mm B&W film. The recommended starting point times for a standard (non-rewind) tank at 20C (68F) is:
FIRST DEVELOPER: 6 min.
RINSE: 2-5 min. (change water frequently)
BLEACH: 1-2 min.
CLEARING BATH: 2 min.
RINSE/RE-EXPOSE (You can't overexpose at this point)
SECOND DEVELOPER: 5 min.
RINSE/FIX/DRY normally.
As a general rule, just remember:
If too dark, increase time or temp. of first developer.
If too light, decrease time or temp. of first developer.
TO ORDER HARD-TO-FIND CHEMICALS call Photographer's Formulary toll free at 1-800-922-5255. (Note: They only sell sulfuric acid in a 48 percent solution so you will need to use 25ml for a liter of bleach instead of the 12ml you would use of concentrated solution.) If you want to get really fancy, try some of their many toners, intensifiers, or reducers on your films or transparencies--experiment first with unwanted films since you don't want to risk ruining your good films.
DISCLAIMER: Potassium Dichromate and Sulfuric Acid are hazardous chemicals which should be treated with extreme care and handled as hazardous waste. If in question, the bleach formula should be made by a qualified chemist. Also, bleach does not keep as well as the other solutions when mixed. For best keeping, you may want to add the potassium dichromate to one-half liter of water to make BLEACH PART A and the sulfuric to a separate half-liter of water to make BLEACH PART B. The two then are mixed together in equal amounts just prior to usage.
ADDITIONAL TIPS:
1. By adding an optional rinse between the bleach and the clearing
bath, you can probably extend the useful life of the clearing bath. But
for most consistent results always use fresh chemistry.
2. If highlights appear to be not fully reversed (I.E. gray image where
there should be white) the bleach is exhausted or you need to increase
bleach time.
3. If yellow stain appears anywhere in film, clearing bath is exhausted
or you need to extend clearing bath time.
4. If fixer erases part of the final image, you did not fully re-expose
or redevelop the film or your redeveloper is exhausted.
5. To use the G-3 tank for negative processing, use regular D-19, then
fix, wash and dry normally.
6. For high contrast applications (such as titles or line work) use
Kodalith developer in both the first and second development stages, or
as a negative developer.
Best of luck--let me know how you come out.
Ed Inman -- E-mail -- edinman@teclink.net
Both PAL and SECAM (another television standard, used mostly in Eastern Bloc nations) use 625 scan lines, running at 50 fields per second. These standards are able to provide higher-quality images than the U.S. standard described below.
It should be noted that the original U.S. television standard for black-and-white transmissions provided for 30 frames/60 fields per second, but had to be revised to allow for color. When black-and-white shows are broadcast by a color station, the TV station can either broadcast at 30 fps, or broadcast a color burst signal at 29.97 fps. In practice, though, this standard is now ignored.
Early broadcast setups were designed to simply repeat every fourth film frame when a film was to be shown on television. This method comes very close to showing the film at the proper speed (it makes the film about 5% longer (with respect to running time) when it is shown on television, because this method assumes that television runs at 30 fps, rather than the actual 29.97). This results in the following frame relationships:
Television Film Frames # Frame # 1 1 2 2 3 3 4 4 5 4 6 5 7 6 ... ...Modern film-broadcast setups work by making each film frame reproduce alternately on two or three consecutive fields. This scheme provides more-accurate representation of motion, and leaves fewer motion `artifacts' of the film on the television display. This results in the following frame relationships (with fields designated by half-frames).
Television Film Frames # Frame # 1 1 1.5 1 2 1 2.5 2 3 2 3.5 3 4 3 4.5 3 5 4 5.5 4 6 5 6.5 5 7 5 ... ...
Because of its high quality and sophisticated electronics, as well as its ability to easily and gently shuttle film back and forth, it is suitable for production work, and, when used with additional electronic equipment, allows for a huge degree of latitude in color and exposure `correction' (much more so than is afforded a lab's color timer), and allows for much additional creative use, as is often seen in television commercials and music videos. Further, it is capable of producing a transfer of camera negative to which sound may later by synced (from an original sync 1/4" or timecoded DAT tape). Sound synching may also be done during the film transfer.
The original film negatives, after processing, are transferred to videotape, with the film's keycode (barcodes printed on the edge of the film negative by the manufacturer, and containing the same information as the visible `edge numbers') encoded on the tape, often in the Vertical Interval Time Code (VITC) region of the tape. Non-drop-frame timecode is recorded as well. Visible timecode/keycode are `burned in' to the picture as well. The tape is synched with the production sound and is then ready for editing. For non-linear editing, the pictures and sound from the tape are digitized along with the timecode and keycode information.
After editing, the an EDL (edit decision list) is created, with the video non-drop-frmae timecode numbers, along with a keycode number list. Each cut is then verified and the list is sent along with a videotape of the edited version and the negatives to the negative cutter, who then verifies everything again, and produces a cut negative to match the video version.
Of course, theatrical films which are edited in the conventional manner (using a Steenbeck (tm) or Moviola (tm) or similar editing machine, and manually cutting and splicing workprint and magnetic film) do not even need to use videotape formats at all, unless the film will be released to the television or home-video markets, in which case a low- contrast print (or interpositive can be run through a flying-spot scanner with minimal color/exposure correction (this will have been done in the color timing stage of production).
The more complicated method (which is substantially more expensive), is available from companies such as 4MC (tm) (formerly Image Transform (tm) ) in the Los Angeles, California area. They (and others) have developed sophisticated equipment which increases the effective number of lines of resolution in a particular television image, making the film version look somewhat clearer than the TV original. In this system, each of the three primary colors of the image (red, green, and blue) are recorded separately onto separate pieces of film, which are then printed successively onto an interpositive in order to produce a full-color image. The soundtrack is usually recorded from the original videotape onto timecoded DAT or 1/4" tape, which can then be used directly to cut an optical track for the print. This process has been used for several widely distributed films, most notably Hoop Dreams, and, considering the low quality of television images, makes reasonably good-looking films.
This type of system can be improvised, using an ordinary projector, by mounting a `sync block' after the second projector sprocket, and by mounting a magnetic head on the sync block. The picture film is then loaded into the projector, and passed through the sync block, and the magnetic film is on reels, mounted on manual rewinds, and passed through the sync block. Since the film and magnetic film are both in the same sync block, they are guaranteed to stay in sync throughout the reel. Of course, the projectionist must crank the takeup rewind throughout the show, in order to take up the magnetic stock.
Subject: Vinegar Syndrome
There is no known cure for vinegar syndrome. There are many "wive's tales" out there, but none of them has had any scientific backing as of yet.
What causes vinegar syndrome? Well, there are many. The most common cause is improper storage in overly humid environments. Other causes are poor processing and some types of scratch rejuvenation.
So what are molecular sieves? They are small packets which are placed in the cans of deteriorating film. They absorb most of the acetic acid vapors which are being released from the film base. These vapors (which smell like vinegar) are what attack the emulsion as well as the plastic acetate base support. If the sieves are used in tandem with proper cold storage (below 50 degrees F and 40% relative humidity) then this will slow the deterioration down to a crawl.
[snip]
Cleaning your film with commercial film cleaners should be limited to those which do not have any oils in them, if you're cleaning films with vinegar syndrome. Trichloroethane based cleaners, or just straight trichloroethane, is very good. Ecco brand and J&R Film cleaner are good. Vitafilm and Surfaset have silicons & oils in them. Oils tend to trap in the acetic acid vapors, which will hasten the deterioration. Make sure you use a clean velvet or Webril Wipe when doing a cleaning. Unless the print is dirty, however, it's best to leave well enough alone. Passing a film through a cloth can potentially cause scratches. Be very careful to stop periodically and shake out the rag in case dirt builds up in it.
Jim Harwood
jharw91601@aol.com
What is a good method for long term storage of film negatives?
The National Film Board of Canada has begun tests on freezing monopack
color negs, but beyond that I couldn't tell you the long-term effects of
freezing your negative. Some members of the AMIA-L (Assoc. of Moving
Image Archivists) listserv expressed concern that if the proceedure was
not carried-out with great control, then the base, emulsion or both could
be fractured by the excessive moisture content of the emulsion, due to
expansion of the freezing water. There were other issues as well,
but I don't remember them off-hand.
At the present time, I believe the consensus is that the optimal storage temperature is near, but not below, freezing with a relative humidity of 30 - 40%.
Will dessicants in the film cans dry out the film too much?
In a word, yes. Unless you are storing the film in a very humid
place, I would not put sillica gel in the cans. If you are storing
the film in a humid environment and cannot control the atmosphere in any
other way than using sillica gel; store the film in an oversized
can, on cores and laying flat (you should always store film on cores and
laying on-edge - never store on reels and in the upright position). I would
suggest you attach the gel canister to the can lid with pop rivets (or
other non-chemical based method to avoid harmful adhesive fumes) over the
center of the core. If you lay the packet in on top of the roll,
you may cause the film to dry-out in the area direcly beneath the gel and
cause dimensional problems in the future. Check the canister and gel every
two-weeks and turn the roll over to equalize the absorption across the
web of the film. I really don't know how you would monitor the relative
humidity of the can, but a stable atmosphere is critical. Cycles
of humidity and extreme dryness can cause severe stress on the emulsion;
causing fractures, across the web shrinkage and maybe even vinegar syndrome.
Who knows?
Also, don't store film in tight-fitting cans; let it breathe. Safety has a tendency to go vinegar if sealed-up in a can (not so much if the temp is low), so keep the film in loose-fitting, oversized cans.
If you can afford it, throw in a few molecular sieves per can; it can't hurt (at least as far as we know!).
If the ideal condition is below 50 degrees at 40% relative humididy,
would it be a good idea to devote a refrigerator to storing my original
negative for my films?
I think so. The greater volume of air would be easier to stabilize
and maintain a good relative humidity level. A fairly inexpensive
weather station (indoor/outdoor type) could be mounted on the door to keep
a check on the interior without opening the door. I would NOT suggest
you use a "frost-free" type of refrigerator, as they remove humidity to
keep-out frost and could freeze-dry your film. If the fridge tends
to keep a dry atmosphere; put a few damp rags in a film can, punch
a few holes in the top and place it in the bottom of the refrigerator.
If too damp, use sillica gel cansiters to lower the RH. You will
have to experiment to find a method of regulation, but it should not be
too hard.
Is freezing it worse than refrigerating it? Will the wrong
temperature or humidity wreak havoc (sp?) on glue splices?
At the present time, I would say cold storage, but don't freeze just
yet. Until more testing is conducted, try a method that has had some
success in the past.
As for the splices; they would be my least worry. A cement splice can be remade without too much fuss; and without losing a frame. I would worry about fungus, mold, air pollution, solvents and other nasties attacking the emulsion; along with the natural tendency of dyes to fade over time.
The biggest problems in preservation of color negative are:
1. Dye fading - solution: copy when dyes start
to fade. That's about all you can do. Forget digitizing; the
storage medium won't last as long as the original negative and "Who the
heck can afford it anyway ?".
2. Shrinkage of base - solution: maintiain proper
humidity and temp. Make new dupe preservation neg when approaching 0.5%
linear shrinkage of the film. Shrinkage should be measured over the
length of one-foot of film and expressed as a percentage of the total original
distance on a fresh piece of properly-pitched stock (get the right pitch,
it matters!). We use shrinkage-gauges built by Mauer in the 50's;
I don't know what to suggest for a homebrew measuring device. You
start having printing problems (movement and breathing in the printer gate)
at about 0.6 % on "standard" printers. When you exceede that amount,
you have to have it printed on a modified printer; one with the sprocket
teeth cut-down and movement is almost assured when you print that way.
3. Emulsion damage - don't handle the film excessively,
but do exercise the roll at least once a year by rewinding. Some
claim you should store the film emulsion-in (contrary to lab practice!),
but we at the LOC store all our originals emulsion-out. Why? I guess
it's just easier to handle when printing when would emulsion-out.
4. Environmental damage - Solvents, ozone, gases, etc.
attack the base, emulsion or both. Keep storage areas clean and free
from volatile chemicals and or liquids.
S. Frank Wylie
fwylie@infinet.com
Cinerama (tm) is arguably the most-discussed film format here on rec.arts. movies.tech. It was the first of a series of film formats developed in the 1950's and 1960's in an attempt to bring the audience a larger, more-realistic, better-sounding film experience. The system consited of a six-perf film format, run from three separate strips of film (shot and projected with three cameras or projectors simultaneously), photographed with wide-angle lenses and intended to be projected on a large, curved screen, made up of several hundred individual strips of screen material. Cinerama (tm) sound was reproduced from a separate seven-track magnetic sound reproducer running magnetic film (much like a standard film dubber). Cinerama (tm) equipment utilized standard 35mm-width film, but the three strips combined to feature an image area far larger than even 70mm prints today. This format persisted through the early 1960's, before it was deemed by the producers and distributors as a clunky format, which could easily be replaced with such later (and inferior) formats as CinemaScope (tm) and 70mm/Todd-AO. Nonetheless, many theaters were designed with Cinerama (tm) presentations in mind, and featured the name `Super Cinerama (tm) .'
The following features were shot in Cinerama (tm) :
(courtesy Ralph Daniel 104574.2404@compuserve.com)
CINERAMA MOTION PICTURES
There are three schools of thought regarding Cinerama motion pictures. The first insists that only productions using three interlocked films in both filming and projection qualify as "true" Cinerama. The second believes that anything shown on a Cinerama screen qualifies.
This third school is a list of features conforming to the following criteria: Each was INTENDED BY ITS PRODUCERS to be shown on a deeply-curved Cinerama screen, regardless of the filming technique used.
YEAR STUDIO TITLE
NEGATIVE CINEMATOGRAPH
1951 C'rama This Is Cinerama
3x35mm Cinerama
1955 C'rama Cinerama Holiday
3x35mm Cinerama
1956 C'rama 7 Wonders of
the World
3x35mm Cinerama
1957 C'rama Search for Paradise
3x35mm Cinerama
1958 C'rama South Seas Adv.
3x35mm Cinerama
1958 C'miracle Windjammer
3x35mm Cinemiracle
1960 C'rama Renault Dauphin
(ad)
3x35mm Cinerama
1962 MGM
Wond World Bro's Grimm
3x35mm Cinerama
1963 MGM
How the West Was Won
3x35mm Cinerama
1963 UA
It's Mad (4) World
65mm U.P. 70
1964 C'rama Best of Cinerama
3x35mm Cinerama
1964 BMP
Circus World
35mm(h) S.T. 70
1965 R-S
Mediterranean Holiday
? ?
1965 UA
Greatest Story Ever Told
65mm U.P. 70
1965 UA
Hallelujah Trail
65mm U.P. 70
1965 WB
Battle of the Bulge
65mm U.P. 70
1965 C'rama1 Golden Head
35mm(h) S.T. 70
1966 C'rama2 Russian Adventure
3x35mm 70mm composite
1966 UA
Khartoum
65mm U.P. 70
1966 MGM
Grand Prix
65mm S.P. 70
1968 Security Custer of the West
35mm(h) S.T. 70
1968 MGM
2001: A Space Odyssey
65mm S.P. 70
1968 MGM
Ice Station Zebra
65mm S.P. 70
1969 ABC
Krakatoa - East Java
65mm S.P. 70
1970 ABC
Song of Norway
65mm S.P. 70
1972 MGM
Great Waltz
65mm S.P. 70
1973 C'rama This Is Cinerama
(reissue) 3x35mm
70mm composite
19?? C'rama (untitled--military
nuclear test) 3x35mm Cinerama
codes:
MGM = Metro-Goldwyn-Mayer
UA = United Artists
ABC = American Broadcasting Company Productions
R-S = Reade-Sterling
BMP = Bronston-Midway-Paramount
C'rama1 = Cinerama-Hungarofilm
C'rama2 = Cinerama & Mosfilm (Soviet Kinopanorama)
3x35mm = three 35mm films run simultaneously
35mm(h) = 35mm film run horizontally (VistaVision)
U.P. = Ultra Panavision
S.P. = Super Panavision
S.T. = Super Technirama
And this interesting tidbit:
M.Holiday was shot in 65mm in a process called MCS-70 (that was either Modern Camera Systems or Modern Cinema Systems). The exhibitor/distributor Walter Reade brought the rights to the film, and converted it to a really bizarre 35mm process called ARC-120 (renamed Wonderama), and it played at least one theatre in North Jersey, but I can't remember which. It flopped. They revived the 70mm print and ran it at the Manhattan Warner advertised "in Cinerama." I've been debating with myself for years whether it should be included in a list of Cinerama70 films since it was not filmed with Cinerama70 projection in mind.
Some more stuff about Med Holiday. In Dan Sherlock's most recent
listing of errors in the Hayes/Carr book, he writes: "The first showing
of Mediterranean Holiday using the Wonderama name was March 5, 1964 (not
1965) at the Strand Theatre in Plainfield, NJ on a screen 61 feet wide
and 21 feet high."
Vince
veyoung@aol.com
Most of the standards relate to the proper positioning of the loud- speakers, screen brightness, presence or absence of sound-absorbing material (e.g. seat coverings) in the auditorium, and such. The standards are different for auditoria of differing sizes. A theater which wishes to advertise its THX (tm) certification must not only meet these standards, but also pay a yearly fee to Lucasfilm. THX (tm) theaters receive promo- tional materials and trailers to promote their establishment.
Plenty of these machines (most commonly, Bell & Howell, Graflex, or RCA (tm) ) can be found from schools and industrial users who have switched over to videotape equipment for presenting instructional/promotional materials. They are also available, usually with warranties, from various dealers in used motion picture equipment. New machines are available from the Japanese manufacturer Eiki, but they cost in excess of $1200, and are sold by audiovisual dealers.
For those who want screen images larger and brighter than a tungsten bulb will allow, Bell & Howell and Graflex both made 300-watt portable MARC projectors, which use an external power supply to drive a small metal-arc bulb (much like modern HMI lamps). The power supplies are no longer made, and are difficult to find; if broken, they may be difficult to repair. These machines generally go for $300-500.
When buying a projector, make sure that it is capable of holding at least 1600' reels (a two-hour feature usually comes on 3 1600' reels), as some older models do not hold this size. New projectors take reels up to 2300'. Be sure to get several take-up reels of the largest size the projector will hold. If a big images is desired from a short `throw,' then a shorter length lens is needed (most projectors come with a 2" lens; 5/8", 1", and 1.5" are also available and give bigger pictures). If possible, try to get an extra set of belts (motor drive, front feed arm, rear take-up arm) for the projector to have on hand in case one breaks. 'Scope lenses are available for showing anamorphic prints.
It's always good to have a splicer on hand, and there are several models which are commonly used. The Bolex cement splicer, guillotine-style tape splicer, and Maier-Hancock hot splicers are all commonly available, and usually go for $50-150.
For 35mm, most people like the guillotine-style tape splicer (which is what editors use), which usually goes for $150. These can be acquired from dealers or from editing supply houses.
On the internet for purchasing used prints for home use, one should
check out the following URL, with for sale bulletin boards updated regularly
from:
http://www.film-tech.com
Prints for public performance showings can be rented from several companies,
all of which have catalogs of their films, most notably:
Swank Motion Pictures, Inc.
350 Vanderbilt Motor Parkway
Hauppauge, N.Y. 11787-4305
(800)-876-3344
http://www.swank.com/
Coming soon - information on two- and three-strip Technicolor, Eastmancolor, and a whole bunch of other processes. In the meantime see http://www.simplecom.net/widefilm/ for some information on early color film processes.
16mm - 40 35mm - 16 70mm - 12.8
/------------------------------------------------------------------\ | Time | Reg. 8mm | Sup. 8mm | 16mm | 35mm | |----------|-------------|-------------|-------------|-------------| | 1 sec. | 24 frames | 24 frames | 24 frames | 24 frames | | | 3.6 inches | 4 inches | 7.2 inches | 18 inches | |----------|-------------|-------------|-------------|-------------| | 10 sec. | 3 feet | 3 1/3 feet | 6 feet | 15 feet | |----------|-------------|-------------|-------------|-------------| | 30 sec. | 9 feet | 10 feet | 18 feet | 45 feet | |----------|-------------|-------------|-------------|-------------| | 1 min. | 18 feet | 20 feet | 36 feet | 90 feet | |----------|-------------|-------------|-------------|-------------| | 3 min. | 54 feet | 60 feet | 108 feet | 270 feet | |----------|-------------|-------------|-------------|-------------| | 5 min. | 90 feet | 100 feet | 180 feet | 450 feet | |----------|-------------|-------------|-------------|-------------| | 10 min. | 180 feet | 200 feet | 360 feet | 900 feet | |----------|-------------|-------------|-------------|-------------| | 20 min. | 360 feet | 400 feet | 720 feet | 1800 feet | |----------|-------------|-------------|-------------|-------------| | 30 min. | 540 feet | 600 feet | 1080 feet | 2700 feet | \------------------------------------------------------------------/
Lens | <---------- Distance in Feet From Screen to Film -----------> | Focal | | Length | 8' | 10' | 12' | 15' | 20' | 25' | 30' | 35' | --------|-------|-------|-------|-------|-------|-------|-------|-------| | 4'9" | 5'11" | 7'2" | 9'0" | 12'0" | Width of Picture | .64" | 3'6" | 4'5" | 5'4" | 6'8" | 8'11" | Height of Picture | --------|-------|-------|-------|-------|-------|-------|-------|-------| | 3'11" | 4'11" | 5'11" | 7'6" | 9'11" | 12'6" | - | - | .75" | 2'11" | 3'8" | 4'5" | 5'7" | 7'5" | 9'3" | - | - | --------|-------|-------|-------|-------|-------|-------|-------|-------| | 2'11" | 3'8" | 4'5" | 5'7" | 7'5" | 9'4" | 11'3" | 13'1" | 1" | 2'2" | 2'9" | 3'4" | 4'2" | 5'7" | 6'11" | 8'4" | 9'9" | --------|-------|-------|-------|-------|-------|-------|-------|-------| | 1'11" | 2'5" | 2'11" | 3'8" | 4'11" | 6'2" | 7'6" | 8'9" | 1.5" | 1'5" | 1'10" | 2'2" | 2'9" | 3'8" | 4'7" | 5'7" | 6'6" | --------|-------|-------|-------|-------|-------|-------|-------|-------| | - | 1'10" | 2'2" | 2'9" | 3'8" | 4'8" | 5'7" | 6'6" | 2" | - | 1'4" | 1'8" | 2'1" | 2'9" | 3'5" | 4'2" | 4'10" | --------|-------|-------|-------|-------|-------|-------|-------|-------| | - | 1'5" | 1'9" | 2'2" | 2'11" | 3'8" | 4'5" | 5'3" | 2.5" | - | 1'1" | 1'3" | 1'8" | 2'2" | 2'9" | 3'4" | 3'11" | --------|-------|-------|-------|-------|-------|-------|-------|-------| | - | - | - | - | - | 3'1" | 3'8" | 4'4" | 3" | - | - | - | - | - | 2'3" | 2'9" | 3'3" | --------|-------|-------|-------|-------|-------|-------|-------|-------| | - | - | - | - | - | 2'7" | 3'2" | 3'8" | 3.5" | - | - | - | - | - | 1'11" | 2'4" | 2'9" | --------|-------|-------|-------|-------|-------|-------|-------|-------| | - | - | - | - | - | 2'3" | 2'9" | 3'3" | 4" | - | - | - | - | - | 1'8" | 2'1" | 2'5" | ------------------------------------------------------------------------| Lens | <---------- Distance in Feet From Screen to Film -----------> | Focal | | Length | 40' | 45' | 50' | 60' | 75' | 100' | 125' | 150' | --------|-------|-------|-------|-------|-------|-------|-------|-------| | 10'0" | 11'3" | 12'6" | - | - | Width of Picture | 1.5" | 7'5" | 8'4" | 9'4" | - | - | Height of Picture | --------|-------|-------|-------|-------|-------|-------|-------|-------| | 7'5" | 8'5" | 9'4" | 11'3" | 14'0" | 18'9" | 23'5" | 28'2" | 2" | 5'7" | 6'3" | 6'11" | 8'4" | 10'5" | 13'11"| 17'6" | 21'0" | --------|-------|-------|-------|-------|-------|-------|-------|-------| | 5'11" | 6'8" | 7'5" | 9'0" | 11'3" | 15'0" | 18'9" | 22'6" | 2.5" | 4'5" | 5'0" | 5'7" | 6'8" | 8'4" | 11'2" | 13'11"| 16'9" | --------|-------|-------|-------|-------|-------|-------|-------|-------| | 4'11" | 5'7" | 6'2" | 7'5" | 9'4" | 12'6" | 15'7" | 18'9" | 3" | 3'8" | 4'2" | 4'7" | 5'7" | 6'11" | 9'3" | 11'7" | 14'0" | --------|-------|-------|-------|-------|-------|-------|-------|-------| | 4'3" | 4'9" | 5'4" | 6'5" | 8'0" | 10'8" | 13'4" | 16'1" | 3.5" | 3'2" | 3'7" | 3'11" | 4'9" | 5'11" | 7'11" | 9'11" | 12'0" | --------|-------|-------|-------|-------|-------|-------|-------|-------| | 3'8" | 4'2" | 4'8" | 5'7" | 7'0" | 9'4" | 11'8" | 14'0" | 4" | 2'9" | 3'1" | 3'5" | 4'2" | 5'2" | 6'11" | 8'8" | 10'5" | ------------------------------------------------------------------------|
Copyright © 1993, 1994, 1995, 1996, 1997, Nikos Drakos, Computer Based Learning Unit, University of Leeds.
The command line arguments were:
latex2html faq2.tex.