In honor of Preservation Week, I thought it was high time to do a post on our film preservation program.
Cellphone pictures of a few nitrate negatives from
the Lincoln Wade Barnes Photographic Negatives Collection
First off, what is film and why was it so ubiquitous for so long? The first 70 years of photography were dominated by images created on metal and glass (daguerreotypes, ambrotypes, tintypes, glass plate negatives). These technologies had some significant limitations – they were bulky, fragile and difficult to use. The advent of the first plastic film base in the 1880s was revolutionary. Nitrocellulose film, or nitrate film, was light, flexible, portable and could be produced on an industrial scale. Film allowed for an explosion in amateur photography and the invention of motion pictures. Nitrate film had the major disadvantage of being highly flammable and degrading in a relatively short time frame. Cellulose acetate film base (popularly known as “safety film” in the early years because it was not flammable) was under development beginning in the 1910s and was fully adopted by the early 1950s. Acetate film has only been superseded by digital photography in the past couple decades.
Why do we need to preserve film?
It is easy to understand the need to preserve nitrate film – no one wants a fire hazard in their collection and many nitrate negatives show clear signs of decay. Ultimately, very decayed nitrate negatives will turn either to dust or goo, completely destroying the image. Acetate film also decays, causing the film base to shrink, warp and become brittle with time. For photographic film, this can cause bubbling and channeling between the image or emulsion layer and the film base.
For motion picture film, the shrinkage of the film base can make it so that the sprocket holes in the film no longer match the holes in the projection equipment, causing the film to tear or break when projection is attempted. Advanced decay can cause curling, spoking (see below), warping and breakage.
In addition, color dyes used in photograph and motion picture film are very sensitive fading with time and detrimental environmental conditions. While it is often possible to recover the images from damaged acetate film, it is a very expensive and time consuming process that involves separating the emulsion layer from the film base and carefully adhering it to a new polyester film base. Unfortunately faded dyes can not be recovered.
What is Amherst doing to preserve our film?
Cold storage is hands down the best way to slow the chemical reactions that cause decay in nitrate and acetate film and color dyes. Storage below 30 degrees Fahrenheit extends the life of film by hundreds of years. (This calculator from the Image Permanence Institute allows you to explore the life span of acetate film under various environmental conditions.) With the generous support of the college, we’ve been able to install two freezers for storing our film materials. Our nitrate films are now all housed in a special flammable materials freezer and we are steadily moving our acetate film materials into a new walk-in freezer that will ultimately house all of our acetate film collections – negatives, slides and motion picture film.
Because neither of our freezers have humidity control, we bag each box of film that goes in the freezer in moisture proof packaging using the protocols designed by the National Park Service. The materials in each box are packed carefully to reduce motion (film is very brittle when frozen), and each box is packed in two layers of vapor barrier bags. Inside each bag is a humidity monitoring card that we use to make sure that seals on the bags have not failed during storage.
Olivia Gieger ’21 packaging film from the Amherst College Football Film collection
If researchers need to work with any of the frozen materials, we can remove them from the freezer and after a 24 hour equilibration period, they can be freely used.
Cold storage allows us to stabilize the condition of our film based materials so that they can be used for centuries to come. It also allows us to focus our digitization and preservation reformatting efforts on materials that have a more urgent need for attention, such as audio-visual materials on magnetic tape (look for a post on legacy AV media digitization in the coming months!)
This page created by the Image Permanence Institute has a lot of great information about identifying types of film and levels of deterioration and tools for cold storage planning.
The National Film Preservation Foundation is a key organization in the United States providing funding and information on motion picture film preservation. The Film Preservation Guide available as a free pdf on their website is a great introductory text for cultural heritage institutions.
This technical preservation guide from the National Film and Sound Archive of Australia includes a section on preservation at home for film, audio, video and still photographs.
This guide by the National Parks Service demonstrates the step by step procedures for implementing cold storage.