Film identification is essential for conservation professionals and archivists, as it provides vital information about the film’s format, origin, and potential degradation risks. Identifying a film’s format and emulsion type can guide preservation strategies, repair methods, and storage conditions.

This section discusses various common and obsolete film formats used in Australia, as well as the importance of identifying specific features such as perforations, edge markings, and camera keys.

Current formats

• Super 8: A popular format for home movies, introduced in 1965 by Eastman Kodak.
• 16mm: Widely used for both professional and amateur filmmaking. It is commonly used for documentaries, educational films, and television.
• 35mm: The most common professional format for motion picture production and distribution.

Obsolete formats

These formats are no longer commercially supported in Australia, although they may still be used in private hands or specialist venues.

• Standard 8: Originally introduced in 1932 as Regular 8, it became the precursor to Super 8.
• 9.5mm: Introduced by Pathé Frères in 1922, primarily used for home movies.
• 28mm: Popular in the early 20th century but eventually discontinued.
• 70mm: Used for large-scale productions but replaced by digital formats in many applications.

Some formats, such as 22mm and 17.5mm, experienced brief popularity before becoming rare in Australia (Brouard et al., 2021).

Notable film formats and their characteristics

35 mm film

35mm has been the dominant professional film format from the beginning of commercial motion pictures. It became the standard for both the Lumière brothers' Cinematograph and Thomas Edison's Kinetoscope.

In 1917, the Society of Motion Picture Engineers (SMPE) published the first widely adopted standard for 35mm film, specifying the width of the film and the position of the frames relative to the perforations (SMPE, 1917).

This format traditionally has 16 frames per foot (each frame is approximately 24.89mm × 18.67mm), and it is often referred to as the "full-frame" format. Over time, variations such as 3-perf pull-down have been introduced, typically used for specific applications, such as animation.

28 mm film

Introduced by the Pathé Film Company in 1912 under the name Pathé Kok, 28mm film was initially used for home movies and amateur filmmaking. It was unique in that it featured three perforations per frame, with variations in perforation design between the US and Europe.

The film stock was available in both nitrate and safety bases, with nitrate used for camera negatives and safety film for projection prints (Koszarski, 1994).

There are approximately 20 frames per foot on 28mm film, and it remains a significant part of early home cinema history.

16 mm film

First introduced by Eastman Kodak in 1923, 16mm was designed to provide a more affordable, non-flammable alternative to 35mm for amateur filmmakers.

Over time, it became widely used for educational, industrial, and documentary filmmaking. 16mm film was initially perforated on both sides of the film strip, but later versions were produced with single-sided perforations to accommodate soundtracks.

16mm is divided into two perforation geometries: A-wind and B-wind, referring to the position of perforations relative to the emulsion (Meyer et al., 2020). A-wind is used for projection, and B-wind is used for camera negatives.

9.5 mm film

Introduced in 1922 by Pathé Frères as part of their Pathé Baby system, 9.5mm film was designed as a more compact alternative to 16mm film for amateur filmmakers.

The film is perforated with a single central perforation between each frame, allowing for larger image sizes. Despite its initial popularity, it was eventually phased out in favour of other formats, such as 16mm.

Perforations and their role in film identification

Perforations serve as the primary means of transporting film through projectors, cameras, and other equipment. The shape and size of perforations, as well as their spacing (known as the pitch), are critical identifiers for film formats.

Each film manufacturer historically produced its unique perforation shape, but in 1917, the Bell and Howell perforation became the industry standard (Meyer et al., 2020).

There are several types of perforations used in motion picture films:

• Bell and Howell: Standardised in 1917 and used for most film formats until the introduction of new types like KS for positive prints.
• Pathé Perforations: Early Pathé films employed perforations similar to those of the Bell and Howell type, with slight variations in shape.
• Cinemascope Perforations: Adapted from the KS type to accommodate the wider image and soundtrack of the 35mm Cinemascope format.

Perforation Pitch refers to the distance between each perforation. The most common pitches are:

• Short pitch (4.74mm) used for laboratory stock and intermediate films.
• A long pitch (4.75mm) is used for standard projection prints (Kodak, 2021).

Emulsion types

Films are categorised by their emulsion type, which refers to the purpose for which the film was designed.

This classification helps in identifying the primary use of the film—whether for original photography, duplication, or distribution. These are the main categories.

Camera emulsions

These emulsions are used in camera negatives for original photography. They are designed to handle the demands of film exposure and high-quality image capture during shooting.

They include both single-perforation and double-perforation formats, depending on the camera system (e.g., single-perf for certain types of cameras and double-perf for professional cameras).

Examples include:

• Camera Negative (single perf)
• Camera Negative (double perf)
• Reversal (single perf).

Laboratory emulsions

These emulsions are primarily used for duplication processes. They are often employed for making duplicate negatives, intermediate positives, or fine-grain positives during the post-production process.

Examples include:

• Duplicate Negative
• Intermediate Positive (dupe pos/fine grain)
• Colour Reversal Intermediate (CRI).

Release prints

These are used to produce final copies of the film, intended for distribution to theatres or for home viewing. This category is highly specialised, often requiring emulsions that can endure long-term handling and multiple screenings.

Examples include:

• Composite Print (optical soundtrack)
• Sound Negative.

Reversal emulsions

Reversal emulsions are unique in that they enable the direct creation of positive images from negatives without requiring an intermediate step. These emulsions are widely used in home movies and speciality films for their simpler processing.

Examples include:

• Reversal (double perf)
• Reversal (magnetic sound).

Aspect ratios

The aspect ratio is the proportional relationship between the film's width and height. Early film was created with a full-frame ratio, typically around 1.33:1, due to the limitations of early film equipment.

The introduction of sound on film led to a shift in frame size to accommodate audio tracks, resulting in a 1.37:1 ratio (also known as the Academy aperture), which is slightly narrower than the original Frame.

• Full Frame (1.33:1): Early film format, with dimensions of 24.89mm x 18.67mm between the perforations.
• Academy Aperture (1.37:1): Slightly narrower than full Frame, used for sound films.

With the advent of television and the need for a more rectangular image, producers introduced wider aspect ratios, including 1.66:1 and 1.85:1. These formats allowed for a more cinematic viewing experience, mimicking the natural field of human vision.

Over the years, additional widescreen formats, such as anamorphic (2.35:1, 2.39:1), were developed to enhance the cinematic experience.

Comparison of widescreen ratios

Widescreen formats employ specialised anamorphic lenses, which compress the image horizontally during filming. When projected, the image is 'un-squeezed' through another lens, restoring the original proportions.

This technique is essential for formats like CinemaScope (2.35:1) and Vista Vision.

Edge markings and camera keys

Film manufacturers often add edge markings to identify key information about the film stock. These markings enable archivists and conservators to identify the film's manufacturing date, emulsion type, and other critical details essential for preservation and restoration.

Film manufacturers often printed identifying marks along the edge of the film. These markings could include:

• manufacturer's name
• emulsion type
• film stock information.

Kodak

Kodak has been a pioneer in edge marking systems, dating back to 1913, with stencil-style marks, such as 'EASTMAN', on their films.

By 1916, Kodak began using coded symbols after the word 'KODAK' to indicate the year of manufacture, a practice that continued for nitrate film.

For acetate films, the symbols are marked after 'SAFETY FILM'. These codes help to identify the production year and material used for the film base.

Date code edge marking

The following are the Kodak stock date edge codes for nitrate and acetate films:

• 1916: circle
• 1917: square
• 1918: triangle
• 1919: 2 circles
• 1936: circle
• 1937: square
• 1938: triangle
• 1939: 2 circles
• 1956: circle
• 1957: square
• 1958: triangle
• 1959: 2 circles.

These markings serve as a valuable tool for identifying film generation and the associated degradation potential, as they allow conservators to trace back the production year of specific prints.

Fujifilm

Fujifilm introduced a date coding system for their 35 mm and 16 mm films. Their code format consists of a 2-digit year followed by a quarter code indicating the three-month period in which the film was produced. For example, JM for January to March, JS for July to September.

A film produced between July and September 1919 would be coded as '19JS'.

Print-through

Print-through occurs when an image from one generation of film is transferred onto another, especially during duplication. This transfer happens when the entire width of the film is exposed to light.

Print-through can help identify the generation of the film. However, it can also be a source of confusion if it leads to the appearance of incorrect edge markings or multiple date codes from various generations.

For example, a nitrate print-through image may display 'NITRATE' text, which could mistakenly appear on a safety film or newer copy, resulting in misidentification.

Camera keys

Some cameras include identifying marks known as camera keys. These marks, often located near the aperture, indicate the type of camera used to shoot the original film. This information is crucial for establishing the provenance of the film and ensuring its historical context is preserved (Brouard et al., 2021).

Many manufacturers included a camera key to identify the specific type of camera used to shoot the original film. This small aperture or element on the aperture frame serves as an important tool for documenting the film's provenance.

The camera key is essential to understanding the film's origins, and it is crucial that it is preserved intact throughout the conservation process.

For example, a Kodak Cine B f3.5 camera was produced between 1926 and 1931. The camera key marking on the film identifies the specific camera used during filming and, when combined with other information like emulsion type and date code, provides a rich context for the film's historical value.

Comparison of full frame, Academy frame and anamorphic formats

Early films were shot in the full-frame format (approximately 1.33:1 aspect ratio), with a frame size of 24.89 mm × 18.67 mm. However, with the advent of sound-on-film, the frame size was reduced to accommodate the addition of optical soundtracks, resulting in the Academy frame (1.37:1 aspect ratio, with a frame size of 22 mm × 16 mm).

To accommodate widescreen formats, filmmakers began using anamorphic lenses that compress the image horizontally during filming, which is later 'un-squeezed' during projection. This allows for wider aspect ratios (such as 2.35:1 or 2.40:1) without requiring a larger film format.

Conclusion

Film identification is a crucial aspect of preserving film history, as it enables the accurate categorisation of films based on their format, type, and manufacturing details.

Through the careful examination of perforations, edge markings, camera keys, and aspect ratio, archivists can deduce essential information about a film's origins and condition.

As film technology continues to evolve, understanding these identification techniques remains vital for proper conservation and archiving.