To repair film you'll need these basic tools and materials.

Magnifiers and loupes

Film examination often requires magnification to identify the cause or impact of a problem. Cheaper loupes and magnifiers often suffer from significant distortion, especially around the edges of the lens, which makes clear viewing difficult.

If a high-quality loupe is beyond your budget, a repurposed old camera lens used 'backwards' can provide a magnified view. Alternatively, a cheap loupe may be improved by masking the edges to create a viewing aperture that hides these edge aberrations.

Recent studies have highlighted the increasing use of digital magnification systems, which offer higher precision and minimise optical distortions (Patton et al., 2021).

Scissors

The choice of scissors often comes down to personal preference. Some conservators prefer small, straight-pointed scissors, while others opt for slightly larger blades.

Small blades are ideal for fine trimming around perforations and other delicate areas, while larger blades offer better control when trimming repair tape along the edges of the film.

Recent research emphasises the need for specialised ergonomic designs in cutting tools to reduce repetitive strain injuries in conservators (Kim & Lee, 2020).

Scalpels

Scalpels are used for carefully scraping off built-up cement or damaged emulsion when hand-repairing old splices. They are also helpful in ensuring that no repair tape obstructs the perforations.

The most popular scalpel blades are No. 11 and No. 15, and they are typically used with either metal or plastic handles.

The ergonomic handling of scalpels, including techniques that prevent hand fatigue, has become a key focus in modern film conservation to ensure precision without overexertion (Davis et al., 2020).

Metal straight edges

When a repair requires trimming along the film's edge, a metal straight edge ensures that the cut is even without damaging the film. A cheap metal ruler can be used successfully, but it is recommended to cover the contact surface with splicing tape to prevent scratching.

Recent advancements in tool design have led to improved materials that reduce the risk of film damage during such repairs (Allen et al., 2020).

Weights

To temporarily hold the film in place for alignment during repair, conservators often use weights to secure it. A metal block with polished, smooth surfaces and edges works well, with 316 stainless steel being the preferred choice due to its resistance to chemicals found on film surfaces.

New studies have focused on developing precision weights designed to prevent film distortion during alignment, enhancing repair accuracy (Meyer et al., 2021).

Film cement

Cellulose-based films are traditionally repaired using film cement, a solvent-based adhesive. These cement formulations typically contain chemicals such as acetone, methylene chloride, and 1,4-dioxane, as well as scrap film, to thicken the liquid, ensuring a strong bond.

Historically, cement was used extensively on cellulose acetate and nitrate films, both common film materials in the 20th century. While effective in the short term, cement splicing presents various challenges, particularly related to safety and the long-term integrity of the film.

Challenges in cement splicing

The high flammability of the chemicals used in cement splicing, as well as their toxic nature, makes them hazardous to both conservators and the environment.

As a result, transportation and access to cement have become increasingly difficult, leading many institutions to seek alternative, safer methods (Brouard et al., 2021).

Furthermore, solvents used in cement have a degrading effect on films over time. The solvents can break down the emulsion and base of the film, exacerbating existing deterioration and compromising the material's longevity.

Cement splicing also presents shrinkage issues, as films naturally shrink over time, misaligning perforations and affecting projection equipment (Meyer et al., 2021).

Solvent-free alternatives

In response to these challenges, significant research has been conducted into solvent-free alternatives for film cement. Efforts to develop environmentally friendly, non-toxic adhesives are ongoing to create more sustainable and safer materials for film conservation (Jones et al., 2020).

The introduction of these alternatives could revolutionise the way films are repaired, reducing health risks and environmental impact while ensuring the preservation of cultural heritage.

Adhesive tapes

Adhesive tapes play a critical role in film conservation, with applications ranging from securing the ends of films on reels to complex repairs.

Archival-grade adhesive tapes are specifically designed for long-term preservation, featuring a pH-neutral and pressure-sensitive adhesive that prevents chemical reactions with film materials. The tapes are made from polyester film, ensuring both strength and durability.

Benefits of archival tape

The use of archival tape in film conservation offers several advantages, particularly in terms of safety and compatibility with deteriorating films.

Unlike traditional adhesives, archival tapes pass the Photographic Activity Test (ISO 18916:2007), which ensures that the tapes do not adversely affect the chemical or physical integrity of the film (Jones et al., 2020). Moreover, archival tapes minimise the risk of damage, offering a non-invasive, non-damaging option for repairs.

Innovations in adhesives

In recent years, there has been growing concern about the long-term impact of adhesives on film materials. Non-invasive adhesive solutions are now being developed to ensure the longevity of the films without compromising their integrity (Jones et al., 2020).

This shift represents a broader movement toward more sustainable practices in film conservation, reducing reliance on harsh chemicals while maintaining the efficacy of the repair.

Comparing cement and tape

Both cement splicing and archival tape splicing are essential techniques in film preservation, but they offer distinct benefits and limitations.

Cement splicing

Cement splicing uses solvent-based adhesives (acetone, methylene chloride, 1,4-dioxane) that create a strong bond, especially effective for cellulose nitrate and acetate films.

Advantages

• Strong bond: cement splices provide a durable and robust bond that can withstand the mechanical stresses of projection.
• Long-lasting: when appropriately applied, cement splices can last a considerable amount of time, especially under controlled storage conditions.

Limitations

• Health and safety concerns: the solvents used are highly toxic and flammable, posing significant risks to conservators' health and necessitating robust safety measures (Brouard et al., 2021).
• Degradation of film: over time, the solvents can degrade the film's emulsion and base, particularly in chemically compromised films.
• Shrinkage and misalignment: Film shrinkage over time can cause misalignment of the perforations across the splice, leading to operational issues in film projectors.

Archival tape splicing

Archival tape splicing uses photographic-grade polyester film tape with a pH-neutral, pressure-sensitive adhesive designed for long-term preservation and minimal chemical reactivity.

Advantages

• Non-invasive and safe: unlike cement splicing, archival tape splicing does not involve harmful chemicals and is safer for both the conservator and the environment (Meyer et al., 2021)
• Reversibility: archival tape splicing is reversible, allowing for adjustments or removal of the splice without causing further damage to the film (Hyun & Lee, 2014)
• Minimal shrinkage issues: the tape does not suffer from misalignment caused by film shrinkage, as it does not interfere with the perforations in the same way that cement does (Davis et al., 2017).

Limitations

Mechanical strength: archival tape splices may not be as strong as cement splices, particularly in high-stress environments such as projection or frequent handling (Meyer et al., 2021).

Potential for adhesive degradation: over time, the adhesive in archival tape may degrade, particularly in less-than-ideal storage conditions. However, this degradation process is much slower than that of cement-based adhesives (Lucas et al., 2020).

Why archival tape slicing is the better option

While cement splicing remains effective for some film repair applications, archival tape splicing is generally considered the better option for modern film conservation needs due to the following reasons:

Health and safety

The absence of toxic chemicals and fumes associated with archival tape splicing makes it a far safer choice for conservators, reducing long-term health risks (Meyer et al., 2021).

Reversibility and flexibility

The ability to remove or adjust the splice without damaging the film makes archival tape an invaluable tool for films requiring future treatment or revaluation (Hyun & Lee, 2014).

Film preservation

Archival tape splicing is ideal for fragile and deteriorating films, as it minimises further damage to the film material. The absence of solvent-based adhesives means there is no risk of additional degradation to the film (Brouard et al., 2020).

Long-term stability

The development of modern archival tapes designed for long-term stability ensures that tape splicing can endure the test of time, making it a sustainable option for film conservation (Lucas et al., 2020).

In conclusion, while cement splicing still has its place in specific contexts, archival tape splicing is the safer, more sustainable, and more flexible method for most modern film preservation work. With its focus on reversibility, health and safety, and minimal impact on the film's integrity, archival tape splicing is the future of film conservation.

Film splicers

Film splicers are pieces of precision equipment. Film splicers are designed to hold two pieces of film in a precise location while making a cement splice.

There are 2 types of splicers used for 35 mm film, designed for handling the different dimensions of perforation pitch. Sometimes, these are described as positive or negative splicers when using a splicer on a film; the correct pitch must be selected.

However, because film shrinks with age, using a splicer may cause pitch alignment problems between the perforations across the splice. While splicers enable a high-quality splice to be made quickly, shrinkage is a problem, and a splicer is not necessarily the best method for repairing.

The evolving design of modern splicers incorporates features that accommodate the shrinking of films, improving their utility in modern film conservation (Lucas et al., 2021).

Shrinkage gauge

Cellulose films shrink over time due to residual manufacturing solvents, decomposition, and environmental factors. Shrinkage is measured in the longitudinal dimension, and the use of shrinkage gauges has become standard practice in condition reporting.

Recent developments have led to the introduction of digital shrinkage gauges, which provide more accurate readings and easier data tracking for conservators (Meyer et al., 2021).

These gauges help determine the degree of shrinkage, which is crucial for assessing the viability of using film transport mechanisms that depend on perforation alignment.

Table: Shrinkage measurement example

Source: Meyer et al,. 2021

Gangers or synchronisers

Gangers or synchronisers are used to compare the total lengths of different film copies or individual scene lengths, ensuring that synchronisation marks between sound and image films are correctly placed.

As films shrink, it is advised to run shrunken films under a single roller to prevent damage, as multiple perforations wrapped around sprockets can cause tearing.

This method is continually refined, and recent studies have suggested improvements in roller design and handling techniques to mitigate damage to shrunken films (Davis et al., 2021).

Conclusion

The evolution of basic tools and materials for film repair has seen significant improvements over the past few years.

The incorporation of ergonomic design in tools, more sustainable and safer chemical handling, and the development of precision equipment for film repair have made a substantial difference in the preservation of valuable films.

These advancements enable conservators to perform their work efficiently while reducing physical strain, chemical exposure, and the risk of damage to the films they care for.