Object of the Month:
Historic Perutz Film Cans and the Acetic Acid Syndrome 

This month we are presenting three special 35mm film cans from the Perutz company that were found in our archive. These historic black and white films not only represent a piece of photographic history, but also illustrate the challenges of archiving and preserving old film material.

The Perutz company, founded in 1896, was a pioneer in the production of photographic films and plates. Perutz became particularly well known for its X-ray films and the high-contrast, double-sided X-ray films developed after the First World War. From 1927, Perutz brought special plates for reproduction photography onto the market and produced the panchromatic Rectepan film from 1932. After the Second World War, Perutz films were particularly important in the television sector, where they were used as standard film material for news and documentary films. The company was finally taken over by Agfa in 1964, although many films continued to be marketed under the Perutz name.

Incidentally, the green color of the film boxes was typical for Perutz and a kind of recognition feature. The company attributed the green color to the particularly high yellow-green sensitivity of the first panchromatic emulsions, a characteristic that was referred to as a green seal in the context of advertising strategy.

When inspecting the Perutz film cans, we immediately noticed a strong vinegar odor – a sure sign of acetic acid syndrome (also known as vinegar syndrome). This phenomenon occurs when older cellulose acetate films react with moist air. The acidic hydrolysis of the carrier material leads to the formation of acetic acid, which not only causes the typical odor, but also leads to the decomposition of the film. The emulsion layer becomes brittle and can detach from the carrier, which makes digitization and preservation of the material considerably more difficult or even impossible. In our case, too, it is no longer possible to reconstruct which images were originally visible on the films.

Cellulose acetate films, also known as safety films, were used from around 1925 to the present day and, unlike the highly flammable cellulose nitrate films, are flame retardant. Despite their safety, they are not protected against acetic acid syndrome, which occurs particularly when stored improperly in warm and humid environments. We can therefore assume that the film cans have not been stored in a cool and dry place as required.

Our three Perutz film cans are therefore more than just historical artifacts; they are also a testament to the challenges that archives and estate managers face in preserving film material. The smell of vinegar and the visible damage to the film material are a reminder of how important it is to store and care for these valuable historical documents properly. 

Pictures: © Peter Schulte, Hamburg