3

The Filmmaking Industry

Throughout the 1890’s, a great many inventors officially presented systems and equipment capable of recording (filming) the movement of real images in a series of photographs taken one after the other and of mechanically recreating the image of these same real pictures before the viewer’s eyes. The reason why the industry developed out of one of these systems (and not precisely the first one) comprises a splendid example of the criteria, which the filmmaking industry has employed throughout its entire history with regard to selecting systems and equipment.

Stroboscopes & Cinématographe

The Kinetoscope

In August 1891, Thomas Edison registered the first patents on the Kinetoscope, a true filmmaking apparatus that he presented publicly two years later. But the Kinetoscope worked on the same stroboscope-related principle as the Zoetrope or other similar inventions, and only one viewer can view a strobe-type viewing system at a time or by a very small group of viewers.

In the Kinetoscope, the film is run in front of a light source (projecting lantern) moving at a constant speed in front of the eyes of the viewer, who views it solely through the peepholes made in a round disc (shutter) located between him and the film and which revolves in the opposite direction from the film, creating a flickered viewing process and therefore breaking the viewing down into viewing segments. By means of the mechanism of persistence of vision, the viewer retains each one of these segments in the form of a still shot, which is immediately replaced by another shot taken of the following image on the film and, on the image of one picture being replaced by that of the next one, both images blend together, giving the eye the sensation of continuous movement.

The Cinématographe

Motion picture filmmaking initially got under way with the adapting of a specially designed mechanical film-feeding system simultaneously on the part of several inventors but which was made popular and further developed by the Lumière Brothers. This system, which incorporated mechanical components originally designed and used for other purposes (i.e. in clocks and sewing machines), converted a circular-type motor impulse into a linear movement with alternating stop/start processes.

On February 13, 1895, the Lumière Brothers patented their Kinetoscope, this being a name, which they soon changed to that of the "Cinématographe". On March 22, the first screening, albeit of a private nature, was held, and on December 28, the Lumière Cinématographe was triumphantly presented at a public gathering in Paris.

The Lumière system implemented the alternating of stop/start processes into the movement of the film, this alternation being synchronized with the movement of a revolving shutter, which shut out, all light whenever the film was not perfectly still. In this system, the images which are shown to the viewer are actually still at the time of viewing, making use of the persistence of images on the retina to put a new image into place by momentarily shutting out all light, this new image blending with the next one in the mind’s eye of the viewer.

Filmmaking & Show Business

On affording the possibility of showing motion pictures to an entire audience at one time by mass-screening devices (additionally providing high quality), the still picture system enabled the motion picture industry to make a place for itself in the world of show business. The success of the Lumière Brothers’ endeavours and their pursuits undeniably having laid the "cornerstone" of a new industry occurred precisely as a result of the prospects, which their mass public screening system had to offer for becoming part of the show business industry.

It was on this basis of mass public screening of series of consecutive photographs, this being a screening which created the sensation of real images in the mind’s eye, that the motion picture industry and all motion pictures were built.

The Filmmaking System

After the Lumière and Edison systems had been combined, the mechanical screening of the image of actual shots was a fully well developed system, which, in practice, is identical to the system, which is still in use today.

A brief description of the design features of this system can be broken down into the following aspects:

A. - Motion pictures (films) were printed on two types of stock: the master film and the prints (the negative and release prints).

Each one of the two types of stock differs from the other with regard to its inherent properties and is processed and handled differently in a way all its own; yet they comprise a whole, the renting asunder of which (due to damage to or the loss of either of the these two types of stock) is damaging to the motion picture in question and even leads to preventing it from ever being seen on the screen again. Both of these types of stock are created and used in a system which can be considered to be symmetrical: camera / laboratory / projector, and, in fact, the first systems built by Lumière were used both as cameras and as projectors.

B. - The picture is comprised of a series of photographs capturing consecutive stages of the movement. These photographs are taken at a constant shutter speed and are screened at the same speed as they were filmed.

C. - The film per se is comprised of a transparent plastic film base and a photographic emulsion comprised of natural gelatins and light-sensitive substances adhered to the film base.

D. - The film moves by way of two types of movement, which, in most systems, are simultaneous and synchronized. The first type of movement is linear and alternating and the second, circular and continuous.

The film is made to move by means of hooks attached to belts or to sprockets wheels. Both of these mechanisms mesh into a number of holes made in the film base by means of which synchronization necessary between the frame and shutter gauge during filming, laboratory processing and screening is achieved.

The combined use of all of these materials, mechanisms and systems in conjunction with the organizational aspects of the show business industry would determine all of the motion picture industry’s both technical and linguistic prospects for future development and even its prospects for making its way through all the way up to the introduction of the electronic imaging systems.

FILM STOCK

STRUCTURE

Motion picture film can be described in physical terms as a "double-decker sandwich" comprised of two different layers of materials: the film base and the emulsion, of totally different physical/chemical properties, which is held together by a combination of substances in both layers which is referred to as the underlying binder base.

Although practically all films are of the same thickness throughout, the overall thickness of films can vary greatly, ranging from 120 to 145 microns (and even thicker and thinner). The film base and the emulsion can also differ greatly in thickness, variations in the relative thickness of both of these component parts ranging from 3% to 10% in the total thickness of the film having been found to exist. The triple-layer emulsions for colour are appreciably thicker than b/w emulsions.

An Unstable Structure

A double-decker sandwich is mechanically unstable, even when the two layers are made up of the same material. The stable "sandwich" materials are always used in an uneven number of layers (3, 5, 7) so that the symmetrically-opposite layers will offset the stress that the differences in humidity and temperature can make in one layer and the other.

In films, the main layer, that is, the film base is stiff and is much less likely to give off or absorb moisture. The thinner of the two layers, that is, the emulsion, is not as hard and gives off and absorbs moisture relatively easily. When the emulsion absorbs moisture, it swells unevenly, and if the way it has been wound on the reel does not allow for expansion, the rising pressure will crush it. On giving off moisture, the emulsion shrinks, lowering the pressure between the loops of film and "loosening" the wound loops of film, making it easier for the film to "lose shape".

This absorbing and giving off of moisture can be offset by means of corrective measures involved in storage, but once damage has been caused, it will be permanent.

FILM BASE DEVELOPMENT

During the early years, while films were still less than 50 meters in length, and there were no distribution channels or permanent screening establishments, each film projectionist (often also the producer of part of the films being shown) could adapt his apparatuses to take whatever films fell into his hands and could even sometimes adapt the films to his apparatuses by screening them optically (?) on the right film base.

The further advancement of filmmaking within the show business industry made it inevitable to accept and even to impose all that which might serve to promote any boost to the normal business in this industry, and the differences between the physical dimensions of the films proper could comprise a stumbling block with regard to their diffusion.

The industry found itself forced to undertake different processes for the standardization of the dimensions and fundamental operating features of its films.

The drafting of the necessary standards for the sizing of all that having to do with the feeding and running of film through cameras and equipment has been one of the processes to which most attention has been devoted and the greatest deal of success has been achieved.

Sprocket Holes

The sprocket holes are the basic factor involved in feeding films through cameras and projectors, as well as in almost all of the equipment and devices which are involved in the use thereof.

Current 35mm, 16mm, 8mm, 65mm and 70mm film standards stipulate the height and width of the sprocket holes and also the radius of the curves where they meet at the corners, the distances to the edge of the film and the tolerances regarding the uneven alignment between the parallel sprocket holes on both edges.

Sprocket Hole Standardization

The dimensions of the four sprocket holes on each edge of a 35mm frame took many years to become standardized and, even so, this standardization has not as yet been fully achieved, two different types of sprocket holes currently being used.

Throughout almost the entire silent screen era, the size and shape of these sprocket holes was decided upon by the individual manufacturers and even by the laboratories following the colouring of the prints.

The sprocket holes varied widely in size, were rectangular, round-cornered or straight-angled, or had short, semicircular sides or comprised of round segments.

35mm Film Sprocket Holes

For 35mm prints, Kodak presented the sprocket hole, which would finally be accepted as the standard, in 1923. This sprocket hole is known as the Kodak Standard (KS) or positive (P) sprocket hole. For negatives, the proposed by Bell & Howell, which was smaller and had rounded short sides, was accepted. This sprocket hole is known as the negative (N) or Bell & Howell (BH) sprocket hole.

On accepting two different sprocket holes for one single type of film base, the industry was attempting to provide for both sturdier screening prints (greater height, providing for easier catching on the rollers and having rounded corners reducing the risk of tears due to pulling) and the best possible stability in the positioning of negatives and dupes in cameras.

At conventions held in 1934 and 1936, an attempt was made to combine these two types, but the majority of the manufacturers opted to keep both. The Dubray-Howell (DH) sprocket hole, having the same height as that of the negative and straight sides like a print, was one of the most well-accepted in this endeavour, yet finally wound up falling into total disuse.

For the prints of the first motion pictures filmed in Cinemascope, a new, smaller sprocket hole was created which left enough room for the 4 tracks of the first "scope". The "S" sprocket hole (known as Fox Hole) is the same height at the negative and has a base of solely 1.98 mm.

Sprocket Holes Standardized for Other Film Size Formats

The exception made for 35mm films has never been made again in any other system, all the other film size formats use the same type of sprocket holes on prints and negatives.

On the 70mm stock and on the 65mm negatives, the (KS) print sprocket hole is used throughout. For the motion pictures filmed using this film size format, a single frame takes up a total of 5 sprocket holes, but spectacular screening systems which use this stock, such as the Omnimax system, can take up to as many as 15 sprocket holes per frame.

Originally, the 16mm stock used to be manufactured with a row of sprocket holes along each edge, but in order to make room for the optical soundtrack, the sprocket holes were taken off one of the edges. At present, film for negatives is being manufactured with one or two rows of sprocket holes, and the stock for prints with one single edge having sprocket holes.

The 8mm (Double 8) film employs the same type of sprocket holes as the 16mm stock, while a new, smaller (1.143 / 0.914 mm); sprocket hole was designed for S8mm films.

Pitch

The width of a film and the space between the inside edges of two consecutive sprocket holes (the edges on which the gate-side claws are placed on feeding a film through cameras and projectors) comprise the dimensions defining the film format size.

The space between sprocket holes (pitch) can vary from one film to another of the same size format depending upon the use for which they are intended.

Short & Long-Pitch Stock

When high-speed, continuous contact printers started being used, the widespread use of two different pitches (short & long) became necessary for professional film stock. In these machines, placing the master and the raw stock, with the emulsion sides together, on an indented roller equipped with a slot for the printing light to shine through prints the motion pictures. On revolving, the roller carries along both films, and the thickness of the master (approx. 140 microns) leads to the raw stock being positioned bending to a wider radius. If both films were of the same size, the raw stock would undergo minor slippage on the master on hooking both films at different heights on the feed roller teeth. When triacetate stock, which was much more stable in dimension than Celluloid stock, first began to be used, it became inevitable for the previously made suggestions of setting different perforation pitches for negatives and prints be accepted.

For stop/star printers, which fit the feed hooks over the sprocket holes before starting to move each frame, these differences in pitch are not necessary.

The pitch for 35mm and 70mm films is of 4.74mm (short pitch) and 4.75mm (long pitch).

For 16mm, the pitch is 7.605 and 7.620.

8mm (Double 8) stock is of one single pitch, that is, 3.810mm. And for the Super 8mm reversible format, the pitch is 4.234mm.

Special Perforations

Generally upon request, raw stock manufacturers will manufacture any type of material with any of the standard hole. 35mm and 33mm stock is also manufactured with perforations affording the possibility of simultaneously two 16mm or four 8mm prints.

35mm Size Format Stock

The joint efforts invested by W. Dickson and G. Eastman in inventing Edison’s Kinetoscope led to the invention of perforated motion picture film and, in practice, set some of the basic dimensions: films approximately 35mm in width with 4 sprocket holes on each side of the frame and 16 frames per foot (304.8mm) of film strip.

The Lumière Brothers also used 35mm film and the 16-frame/foot arrangement, but, in principle, they placed one single round hole at each one of the edges of the frame.

Although it was not until 1916 that international standards began to be set for the purpose of standardizing the basic dimensions of 35mm stock, this stock was that most used right from the start for filming and for making release prints.

Following their official approval by the U.S. film industry, films 35mm in width with four holes per frame would finally become the basic standard for the motion picture industry.

16mm & 9.5mm Size Format Stock

At almost exactly the same time in 1923, Kodak and Pathè presented two new film stock formats for use, in principle, for home movies. In both cases, a safety plastic, cellulose diacetate, was used and, due to its being inflammable, afforded advantages for private consumers. These two new film stock formats were the same right down to their using one sprocket hole per frame, with a 7.620mm pitch and 40 frames per foot of film. Basically, both of these sizes were marketed with reversible emulsions. The 16mm picture quality as well as how lightweight the 16mm equipment led to ready acceptance on the part of professional filmmakers, mainly for filming documentaries and news clips.

The 9.5mm films (also known as Pathè Baby) due to the smaller surface area of their frames and to the mechanical problems and preservation-related trouble stemming from their feeder system based on one single, centrally-located sprocket hole, never made it beyond the home movie environment and wound up practically being ousted from the market when 8mm videotapes came out.

70mm Size Format Stock

Almost from the very birth of motion pictures, 65mm-size stock or larger was used, but it would not be until the sixties when a 70mm printing system with 6 magnetic soundtracks would come into use. For filming, 75mm or 65mm formats were used. From these negatives, it is possible to make smaller-format copies in 35mm scope, and it is also a relatively frequent practice to make some 70mm copies from films shot in 35mm scope format.

The screening systems for curved or super-scope screens employ this type of stock. In some systems, the motion picture is filmed and projected horizontally, and the frame takes up to 15 perforations (71.25mm).

8mm Size Format Stock

In 1933, when 16mm stock started being used in professional filmmaking, Kodak launched a new type of film for home movies, that is, the 8mm (Double 8) film, which would be marketed worldwide and, in the fifties, would become the stock in trade for making home movies.

D-8 film is manufactured on 16mm stock punched with twice the number of sprocket holes on each edge and reversible emulsions. The strips of film are threaded into the camera, one after the other, through both ends; and after developing, the laboratory cuts the roll along its lengthwise axis, thus obtaining two 8mm strips, which are spliced together in, order one after the other.

Kodak and Fuji presented the Super 8 and Single 8 formats in 1965. Their main advantage lay in making use of the emulsion-coated surface for the image area, which almost doubled that of D8 films.

They brought in the "cartridge" or "cassette" concept incorporated to the raw stock. When home video cameras came out, the use of this type of film soon plummeted on the market.

Screening Speed - (1. Silent Screen Era)

Except to create special effects, the number of frames which are viewed within one single second of screening must match up with those recorded within one second of filming.

Visual Continuity & Light Perception

The organs providing humans with their sense of sight can form, transmit and analyse 10-12 images per second. At the same time, the vision centre in the brain retains each individual image for one fifteenth of a second. If the vision centre in the brain receives another image during this fifteenth of a second, the sight mechanisms will create the sensation of visual continuity. Any of the two basic speeds employed throughout filmmaking history (16 i/s and 24 i/s) can amply meet the requirements of viewing continuity.

In laboratory testing, it has been found that the human sense of sight can distinguish up to 48 flashes of light per second, the switching from light to dark not being detected when they take place at higher rates of speed. Therefore, for example, the flickering of lamps operating on alternating current at 50 cycles per second is not visible to the human eye. At slower rates of speeds (i.e. 16/24 times per second), the changes in brightness are perceived as flicker, which becomes more distracting the greater the greater the degree of brightness involved.

Feed & Shutter Synchronization

In the Maltese cross system, which is the system most used for screening, the wheel which transfers the impulse to the film feeder system (the crank disk) must make one full turn to move the Maltese cross once. The Cross is connected to a sprocket wheel, which revolves by one-quarter turns (four sprocket holes) feeding in one frame. Apart from this, the shutter, which is synchronized with the crank disk, shuts out the projector light while the Maltese cross gear roller is feeding the film through. The combination of these mechanisms, visual discontinuity and the persistence of vision afford the possibility of an on/off projection of fixed images being perceived as being shown on the screen with the continuity which is required to provide viewers with the sensation of viewing movement.

Silent Film Shutter & Screening Speeds

For purposes of viewing continuity, it would suffice for the shutter to open and close the aperture once per frame (single-blade shutter). At the speed of silent movies, this means that the screen is lit and goes dark 16 times per second. As the Lumière Brothers and others screening films must have discovered from the start, the picture on the screen flickers unbearably at this rate of speed. The implementation of dual-blade shutters doubled the number of interruptions and provided a somewhat less than full solution to the problem. But the building of permanent theatres equipped with large screens and high-powered arc lamps in the projectors made the shutter flicker unbearably worse, making it necessary to incorporate triple-blade shutters (one of the blades of which was to cover the 90º angle necessary to conceal the feeding of the film) or to step up the screening speed.

A triple-blade shutter shuts out a minimum of 54% of the projector light and also requires a greater deal of precision as regards the operation of the projector head. The need of making the projector arcs more powerful led to it being impossible throughout the entire silent screen era for any consensus of opinion to be reached with regard to filming and screening speeds.

Generally speaking, films were shot at a rate of 16 images per second and were screened however the person screening the film was so minded.

Although the rate of 24 i/s prevented flicker with double-bladed shutters, modern systems are equipped with three-bladed shutters to provide for better light continuity.