Vinegar syndrome (VS) is a breakdown of the triacetate film base causing the release of acetic acid vapours. VS can be almost stopped but cannot be reversed.
The acid is initially released inside the plastic and gradually diffuses to the surface, causing the vinegary smell.
Is It Dangerous
It is not dangerous to person or property.
The decay process follows goes through the following stages:
- Acetic acid is released during the initial acetate base deterioration, causing the vinegar odour.
- The plastic film base becomes brittle. This occurs in the advanced stages of deterioration, weakening the film and causing it to shatter with the slightest tension.
- Shrinkage also occurs during the process. In advanced stages the shrinkage can be as much as 10%.
- As the acetate base shrinks, the gelatin emulsion of the film does not shrink. The emulsion and film base separate causing buckling (referred to by archivists as "channeling").
- Crystalline deposits or liquid filled bubbles appear on the emulsion. This is evidence of plasticisers, additives to the plastic base, becoming incompatible with the film base and oozing out on the surface. This is a sign of advanced degradation.
Here's a rough idea of the stages of decay:
- No VS.
- Vinegar odour. Film still wound on reel without deformation. Slight cupping of the film from edge to edge. Shrinkage under 1%.
- Vinegar odour. Film still wound on reel with minor deformation. Dent in side of film caused by uneven shrinkage. Slight cupping of the film from edge to edge. Shrinkage 1%.
- Vinegar odour. Film still wound on reel with deformations. A number of dents in side of film caused by uneven shrinkage. Cupping of the film from edge to edge. Shrinkage more than 1%?
- Vinegar odour. Film still wound on reel with many deformations. Many dents in side of film caused by uneven shrinkage. Cupping of the film from edge to edge. Shrinkage closing in on 10%? Brittleness? Can no longer run through telecine.
It appears that all triacetate films will eventually succumb to VS. If the film is stored under ideal conditions it may take 50 years before it shows. If the film is stored in cold storage it make take 150 years.
VS can be identified by the strong vinegar odour. VS There are a number of stages that VS goes through:
- cool location
- dry location
- store in a archival can (breathable), not in an air tight can. Air tight cans accelerate the VS process!
- use a A-D strip and check film on a periodic basis for signs of VS
- separate VS inflicted film from non-VS film
Slowing Down VS
Molecular Sieve is a desiccant that can be used to slow down VS. This stuff is similar to those little packets found in many electronic packaging these days. These packets are commonly used to absorb moisture and prevent damage to the electronics. Placing Molecular sieves in film cans absorb the acetic acid and dry the air and film and almost stop the VS process. Using molecular sieve's may however dry the film and there is a debate with regards to where or not drying the film can cause damage. Some say that you simply need to remove the film from the molecular sieves for a period of time before projecting to allow moisture to get back into the film.
Cases of VS Affected Film
Here are two situations that involve VS films.
1) Customer has 5 1000 foot reels of 16mm film in a film shipping box. Each film is in a metal case. The films are of a Sep 7 1963 Lions vs Calgary game in Empire Stadium (Lions won). All the films and the case had a very strong odour of vinegar. I checked out the film and it is slightly shrunken, about 0.7-8% and slightly cupped from edge to edge. The film on the reels looks tightly wound and no "dents" or unevenness caused by excessive shrinking. Tested 100 feet on the Sniper and ran fine. In stage 2.
2) This customer has a 400 foot reel of film in a metal can. The film has a strong odour of vinegar. The film also has a "dent" in one spot of about 1" by .125" deep on the side of the film. The shrinkage is 1%. 50 feet of the film ran fine on the 16mm Sniper. In stage 3.
All the films have been air in the shed for about 3 to 4 weeks and the odour has significantly decreased. To slow down the VS afflicting the films I would recommend to the customers to use molecular sieves and store them in cool locations and not humid. The molecular sieves need to probably be checked on a regular basis. Also, do not store the VS afflicted films with good ones. An A-D strip is also recommended.
I am going to clean these films using the regular solution for case #1 and I may use Filmrenew for case #2.
Transferring VS Affected Film
Stages 1 through 3 can definitely still be transferred using the Sniper 16HD.
Stages and how to transfer:
- Regular cleaning and transfer.
- Regular cleaning and transfer.
- May need to clean using FilmRenew. FilmRenew will take several days to dry. Also, when winding film do a reverse wind to straighten the film. The reverse wind is winding from the top of the right reel (source) to the bottom of the take up reel. And leave it on the take up reel until the FilmRenew is dry. Then wind it back so the film is on the reel normally.
- Will need to use FilmRenew to clean and soak the film. Reverse wind the film and leave the film in FilmRenew for a week or so. Dry and clean the film and then reverse wind again. And leave it on the take up reel until the FilmRenew is dry. Then wind it back so the film is on the reel normally.
- Cannot transfer. Too shrunken.
Treating (sealing) film with plasticiser:
Info on VS and proper film storage, splicing, etc