How to save a film

From disposable commodity to the first film archives

We have a fairly detailed idea of the number of 'lost' films through preserved inventory lists, reviews, and cinema advertisements.

A surprisingly large portion of those films were actively destroyed during the first half of the twentieth century, as film was considered a disposable commodity without cultural or historical value. Additionally, nitrate film was highly flammable, so films were sometimes burned accidentally or irreparably damaged.

The notion of attempting to preserve films took shape quite slowly. In 1919, the Dutch Central Film Archive was established, but it exclusively focused on films deemed to have 'historical value'. Internationally, significant attention was given to the subject in the 1930s, with the establishment of the British Film Institute and the Cinémathèque Française. The precursor to the Eye Filmmuseum, the Dutch Historical Film Archive, was founded in 1946.

Scratches and dust

Archives began to collaborate internationally to exchange knowledge because nearly every film that was brought into an archive had some form of damage.

In fact, virtually every analog film incurs damage through regular use: scratches and marks from frequent projection or splicing done with excessive glue or incorrect tape. Additionally, dust almost always finds its way into the image: particles from the air settle onto the film during projection and become pressed into the emulsion layer as it's wound up, where they adhere. During subsequent screenings, these particles become visible as specks in the image.

Decomposition

Even if a film remains entirely free from this kind of mechanical damage, aging makes the material susceptible to other forms of deterioration. Both nitrate and acetate films are semi-synthetic plastics that slowly decompose when stored at elevated temperatures. The progression cannot be reversed, only slowed down by ideal storage conditions.

During the decomposition of nitrate film, nitric acid is released, which accelerates the process: the film becomes tacky and eventually crumbles to pieces. As the decomposition advances, the film becomes even more flammable.

Vinegar syndrome

While acetate film is indeed not highly flammable, it might be even more susceptible to chemical degradation than nitrate film. However, this was not recognized for a long time: archives did observe that acetate films were beginning to deteriorate, but it took decades for the scale of the problem to be fully understood. This degradation of acetate film is referred to as vinegar syndrome: under warm or humid conditions, the base of the film starts to break down. This process releases acetic acid, which gives off a distinctive sharp acidic odor.

This process also accelerates itself, and affected films can "contaminate" relatively well-preserved films if stored together in inadequately ventilated spaces. Affected films warp, become brittle, and eventually turn sticky. Films that have undergone advanced stages of degradation often cannot be restored or digitized anymore.

Colour

Archives quickly discovered that black-and-white films tend to hold up better over time than colour films. Both nitrate and acetate films are complicated by the presence of colour. Silent films (almost always on nitrate film) were often coloured after shooting, and some of those colourants have compositions that degrade the film base or emulsion.

Colour plays a different kind of role with acetate film: by the time acetate became the standard for producing feature films, various types of colour capture had been developed. Systems like Technicolor, which used separate negatives for different colours that had to be later combined, offered a very stable colour system but were labour-intensive in terms of production.

As a result, another colour system gained prominence, involving the coating of the film with three layers of different colour-sensitive emulsion. Eastman Kodak and Agfa introduced this in the 1930s as a small-gauge film; from the 1950s, "Eastmancolor" began to dominate the feature film industry. However, these colour systems eventually proved susceptible to fading or discoloration over time.

Damp and dehydration

The semi-synthetic nature of nitrate and acetate film bases makes them susceptible not only to decomposition but also to mold and bacteria. As these microorganisms thrive in humid environments, it would make sense to store films as dry as possible.

However, films can also suffer from drying out, leading to shrinkage. This might not always be visible to the naked eye, but in order to play a film, it's necessary for the perforation holes on the film to align precisely with the sprockets of the equipment. Shrinkage could mean that a film that appears to be in good condition at first glance might no longer be compatible with standard equipment. Luckily there is special equipment to scan shrunken films - to a degree.

In a professional film archive, maintaining a controlled humidity level at a cool temperature is essential. Fortunately, this proves to be a sustainable solution for most films. However, even with these conditions, the deterioration process cannot be entirely halted.


Predicting which films will deteriorate the quickest is not always possible, and a decomposing film can potentially "contaminate" relatively unaffected films in its immediate vicinity. This is why all films are subject to periodic checks. Some films eventually undergo freezing. This practice is particularly employed with negatives, as negatives are considered the primary material of a film and are accessed the least frequently from storage.