Detecting performing arts organisations’ films and magnetic tapes affected by vinegar syndrome

In 2015-2016, Het Firmament and PACKED vzw made an inventory of the audiovisual archives in the performing arts sector. A number of these archives contained film content. We suspected that some of these materials had been affected by vinegar syndrome and were already deteriorating, so we used A-D strips to test the acidity levels. Around 72.6% of the material we checked had a pH value of 5 or lower, and so was clearly affected, meaning it had already deteriorated a certain amount. Fortunately, the acidity had only reached the autocatalytic point (pH value: 4.6) in 1.2% of the film stock, and was still in a good enough condition to be digitised. Vigilance and appropriate storage conditions are recommended to prevent further deterioration.

Status

• December 2015: Het Firmament and PACKED vzw use A-D strips to test the archives at Opera Ballet Vlaanderen;
• July - December 2016: Het Firmament and PACKED vzw use A-D strips to test at CAMPO, Damaged Goods, DE MAAN, Kunst/werk, Needcompany, Rosas, STUK, t,arsenaal and Ultima Vez;
• December 2016 - January 2017: Het Firmament and PACKED vzw find a small amount of new film stock at Opera Ballet Vlaanderen and prepare it for transfer to Cinematek;
• December 2016: Cinematek use A-D strips to test films from Kaaitheater.

Issue

In the spring of 2015, Het Firmament, Kunstenpunt and PACKED vzw took the initiative to make an inventory of the audiovisual and digital archives in the performing arts sector. We received useful information from 75 performing arts organisations.^[1] Together, these organisations represent a good cross-section of the performing arts sector currently (or recently) subsidised by the Flemish government. We found 31,047 carriers that could be considered for digitisation.

In 2016, VIAA agreed to digitise the inventoried materials.^[2] By the end of November 2016, 40 performing arts organisations had become VIAA content partners and signed up to have their audiovisual content digitised.^[3] A lot of them had even started registering their carriers in VIAA’s AMS system in preparation for digitisation. We suspected that some of the film content was affected by vinegar syndrome, so Het Firmament and PACKED vzw spent a year investigating the inventoried film content in more detail.

Vinegar syndrome is a deterioration process that can affect films, magnetic tapes and photographic negatives/slides with an acetate base. The decay is autocatalytic, which means that deterioration starts slowly (because there is still only a small amount of the acid that causes it), but quickly accelerates as the chemical reaction continues. The autocatalytic point is the moment when the reaction starts to accelerate exponentially. The base layer of the acetate film or magnetic tape acidifies, which emits an vinegar-like odour and the material becomes brittle and starts to shrink. High temperatures and a fluctuating but relatively high level of humidity in the storage environment speed this process up further. Films, magnetic tapes and photographic negatives/slides are mostly already in an advanced state of deterioration when the vinegar-like odour can be detected. The deterioration process starts much earlier, and can only be detected with e.g. A-D strips (see below) in its early stages.

It’s usually assumed that damage caused by vinegar syndrome cannot be reversed. It can only be slowed down by ensuring the affected materials are properly treated and stored in suitable conditions.^[4] Affected materials also need to be stored separately, to prevent other carriers with an acetate base from also being affected. It is recommended to copy the content stored on the affected material to a new carrier, or to digitise it, to ensure it does not become lost. This is why VIAA wants to prioritise materials affected by vinegar syndrome when digitising the inventoried film content.

CAMPO Azijnsyndroom

CAMPO Azijnsyndroom

Method

Identify the stock and investigate its condition

There are three different ways to detect vinegar syndrome.

1. Vinegar syndrome is named after the smell of acetic acid (in vinegar), which is created when the acetate base layer in films, magnetic tapes and photographic negatives/slides deteriorates. If you can smell vinegar in an archive, it’s very likely that one or more films, magnetic tapes or photographic negatives/slides have already started to decay.
2. Films and magnetic tapes affected by vinegar syndrome often display a series of visually identifiable symptoms:
   • shrinkage;
   • curling and warping (no longer flat);
   • loss of flexibility (no longer so evenly or tightly wound);
   • signs of cracking or warping on emulsion surface;
   • white powder near edges (as the binding layer decays).

3. A third way of finding out if films, magnetic tapes and photographic negatives/slides have been affected by vinegar syndrome is to test them with A-D strips. A-D strips are dye-coated paper strips which can be used to detect the presence of vinegar syndrome in collections, and assess how far advanced it is. The paper strips need to be placed in a sealed can, bag, box or locker together with the films, magnetic tapes or photographic negatives/slides, where they will change colour according to the acid gas produced by the decaying acetate base. The new colour represents a certain level of acidity (expressed in pH) which indicates a certain level of vinegar syndrome deterioration.

In order to confirm that the performing arts sector film content on the inventory had been affected by vinegar syndrome, Het Firmament and PACKED vzw employees visited ten performing arts organisations’ archives over the course of a year.

Het Firmament carried out tests at:

DE MAAN; Kunst/werk; t,arsenaal;

PACKED vzw carried out tests at:

CAMPO; Damaged Goods; Needcompany; Rosas; STUK; Ultima Vez.

Het Firmament and PACKED vzw also carried out tests together at Opera Ballet Vlaanderen. A first series of films from Opera Ballet Vlaanderen were deposited at Cinematek for further inspection in 2016. It appeared that some of this series could not be digitised because of a high degree of damage. The second series of films from Opera Ballet Vlaanderen is still awaiting further inspection.^[5] Cinematek have also tested several films from the Kaaitheater for PACKED vzw and VIAA in the past.

All film cans and boxes were opened for testing with A-D strips. Closer inspection showed that they didn’t just contain photographic film reels, however, but also sometimes associated magnetic audio tapes (sepmag). The film cans sometimes showed signs of rust, including on the inside. A number of film reels were not in film cans, but in plastic bags or cardboard boxes. We sometimes noticed a scent of vinegar, but visual signs of decay (e.g. curling and warping) were very rare. We couldn’t visually inspect the materials very thoroughly because the testing was carried out on site with no suitable equipment available. Cinematek will perform a thorough visual inspection when they register the materials in preparation for digitisation by VIAA at a later stage.

Het Firmament and PACKED vzw placed Danchek A-D strips in around 430 film cans, boxes and plastic bags, These cans, boxes and bags were then sealed again for at least 24 hours. When they were opened again, many of the paper strips had changed colour; some only slightly, but some a lot.

CAMPO Azijnsyndroom

CAMPO Azijnsyndroom

CAMPO Azijnsyndroom

Relocating the affected materials

It was clear from our visits to the performing arts organisations that the majority of the film content affected was being stored in less than optimal conditions. An important way to slow down decay caused by vinegar syndrome is better storage conditions, i.e. at a low (constant) temperature with low relative air humidity. Any film, magnetic tapes or photographic negatives/slides with an acetate base that have already been affected also need to be isolated to prevent the vinegar syndrome spreading.

Het Firmament, PACKED vzw and VIAA propose that the performing arts organisations deposit their photographic film content (and magnetic audio tapes) with Cinematek, a specialist in the storage of (affected) film content. VIAA will then work together with Cinematek to register the film content in preparation for digitisation. Cinematek will inspect and describe the materials further before sending them to the specialist digitisation laboratory.

Results

Significance of the value measured:

Cinematek considers materials with a pH value of 5 or lower to be affected. VIAA considers all materials with a pH value of 5 or lower to be a priority for digitisation. VIAA will start by digitising film content with a pH value between 4.2 and 5.0 before 2020. Film stock with a higher pH value will only be considered for digitisation after that.

Results per value measured:

This means that around 72.6% of the materials tested have a pH value of 5 or lower, and so are clearly affected by vinegar syndrome and in a certain state of deterioration. Fortunately, the acidity has only reached the autocatalytic point in 1.2% (5 items) of the content (pH value: 4.6).

Results per carrier:

Results per performing arts organisation:

Further explanation about the results:

Rosas:

There were often multiple copies per production, and it won’t always be necessary to digitise all these copies, so this was also checked per production:

• Elena’s Aria:
  • 16 mm (original master), b/w, 1 spool: pH 5.5 - 6
  • 16 mm (new master), b/w, 1 spool: pH 5.5 - 6
• Bartok Aantekeningen:
  • 16 mm, b/w, 1 spool: pH 5.5 - 6
• Achterland:
  • 16 mm, 1 spool: pH 5.5 - 6
• Tippeke:
  • super 16, without subtitles, colour, 1 spool: pH 4.8;
  • super 16 (reserve copy), without subtitles, colour, 1 spool: pH 5;
  • super 16, French subtitles, colour, 1 spool: pH 4.8;
  • super 16, English subtitles, colour, 1 spool: pH 4.8.
• Woud (bomen + auto’s):
  • super 16, colour, 1 spool: pH 4.8.
• Just before:
  • super 16, colour?, 1 spool: pH 4.8.
• Crash End:
  • 16 mm, colour?, 1 spool: pH 5.
• Education prescolaire en URSS:
  • 35 mm, colour, 1 spool: pH 5.

The film ‘Fase’ was not investigated because it’s already been digitised by Cinematek (as part of the digitisation of filmmaker Eric Pauwels’ work). A 35 mm copy of Achterland (ATDK film) still needs to be located in the Netherlands. The copy of Müller still needs to be tested.

STUK:

The film reel on the inventory was looked for but not found.^[17]

Ultima Vez:

Not all reels were clearly identified with a production, so classification is per carrier rather than per production:

• Super 8: 63 items pH 5;
• 16 mm: 2 items pH 4.6, 30 items pH 4.8, 45 items pH 5, 3 items pH 5.5;
• 16 mm rushes: 3 items pH 4.8 and 7 items pH 5;
• Super 16: 2 items pH 4.8;
• 8 mm magn: 23 items pH 4.8 and 10 items pH 5.5;
• 16 mm opt audio: 2 items pH 4.6;
• magn audio: 2 items pH 5;
• various: 50 items pH 6.

Author: Rony Vissers (PACKED vzw)