Say, you just bought 10 rolls of film and plan to shoot them in the coming year. Or you have multiple printing papers that you use, some of which you use seldom. How do you store these properly and how do you keep them from developing undesired artifacts, such as a change in sensitivity (speed), contrast, color balance and fog level?
Browsing the online photography fora will bring you a plethora of opinions and experiences with regard to the proper storage of unexposed photographic material. Some people claim that film that had been stored in a freezer for 28 years shows no signs of degradation and can be used without any problems. Others don’t care about storage at all and only get concerned when unexposed film has passed the expiration date by at least 10 years. Without information on the storage conditions, such as packaging, temperature and relative humidity, such examples are useless. To get a more reliable reference, I browsed the technical information made available by the manufacturers and the scientific literature. While the manufacturers seem to be the only ones producing reference papers on storing unexposed material, it is the scientific community of archives that is naturally most concerned with the proper storage of exposed and developed material. The storage of exposed and developed material, I will keep for another day, and will focus in this article on unexposed film. Below I highlight my findings, by using three major references that in my opinion carry authority in the topic.
First of the three is documentation provided by a manufacturer. The Eastman KODAK Company has been producing light sensitive materials for over a century for photography, motion pictures, medical x-rays, and scientific purposes. Its customers need to be able to rely on its instructions for proper storage of the unexposed material. This is not just important for a few rolls of film, but especially more so when their customers buy kilometers of expensive motion picture film or 2500 rolls of Tri-X in bulk. For this reason KODAK’s Technical Reference, E-30 [1] is often quoted as a must-read. I highly recommend reading this reference if you are concerned with storing film for more than 6 months before use.
KODAK recommends that film be used before the ‘Develop Before’ date printed on the packaging, because cosmic radiation will increase the base fog independent of (realistic) storage conditions. To increase its lifetime, film should be stored at a relative humidity (RH) of 50% and the temperatures listed in Table 1.
| Storage Duration (months) | Maximum Temperature (°C) |
|---|---|
| 2 | 24 |
| 6 | 16 |
| 12 | 10 |
| > 12 | -18 to -23 |
As can be seen from the table, a storage temperature below 16 °C is required for storage longer than 6 months. As room temperature is typically around 18 – 21 °C, this implies storage in a refrigerator for the majority of us. KODAK goes on to add that it should be kept at a relative humidity of 50% or less.
I’d like to note here that black-and-white film is much simpler in lay-up than color film. According to Technical Reference E-30, the complex layering of color film makes it more susceptible to aging and degradation because each layer is affected differently or at a different rate. Therefore it is recommended to store color film at a temperature below 21 °C at all times.
The second reference I want to include here, is the 1993 book titled “The permanence and care of Color Photographs” [3] by Henry Wilhelm of Wilhelm Imaging Research. He has affiliations in the Photographic Materials Group of the American Institute for Conservation of Historic and Artistic Works, ISO WG-5 Task Group 3 (standardized accelerated test methods for stability of color photographs and digital print materials) and ANSI/ISO subcommittees for storage standards for black-and-white films and prints, and can be considered an expert in the topic. Although the book is a tough cookie to get through, he recommends storing film at -18 °C and a RH of 30%.
The last reference is the 1997 paper by Adelstein et al. that was published in the Journal of the American Institute of Conservation. The paper, titled the “Moisture Relationships of Photographic Film” [2], explores the way film absorbs moisture under a wide range of conditions. Based on their research, this group recommends that film should be frozen in a frost-free freezer to -16 °C. Before being frozen, it should be packaged in a vapor-tight package at room temperature and conditioned to a RH of 50% or less, although this is only a concern when the room RH is 60% or higher. Although refrigeration is not considered as beneficial as freezing, storage at a temperature of 2 °C to 5 °C is better than storage at room temperature. You may then wrap film in moisture protective packaging, such as cans or polyethylene bags, to prevent damage from high moisture levels that may occur during power outages or malfunctioning of commercial refrigerators.
In summary, we can conclude that even though the exact numbers differ, the scientific and industrial consensus is on refrigeration for short term storage (< 12 months) and freezing under low relative humidity for long term storage (> 12 months). This is in line with the general consensus and practice of most photographers, even though their experiences may vary. Especially now film manufacturers focus on their professional films and have taken many consumer films off the market, proper care and handling of film is increasingly more important. When KODAK filed for bankruptcy in 2012, people thought that was the end of film and bought tri-x by the shiploads. Fortunately, things were not that disastrous (KODAK film is now produced by KODAK Alaris, and Ilford is also still going strong), but there is no guarantee the future of film supply is secure. Knowing how to take care of your film stock is and will remain important.
References
[1] Kodak’s Technical Reference E-30, Retrieved on 29 December 2015 from http://www.kodak.com/global/en/consumer/products/techInfo/e30/e30.pdf
[2] P. Z. Adelstein, J.-L. Bigourdan and J. M. Reilly. “Moisture Relationships of Photographic Film.” Journal of the American Institute for Conservation 1997; 36(3), 193-206. DOI: 10.1179/019713697806124475
[3] H. W. and C. Brower, “The Permanent Preservation of Color Motion Pictures,” in The Permanence and Care of Color Photographs: Traditional and Digital Color Prints, Color Negatives, Slides and Motion Pictures, Grinnell, Iowa, USA: Preservation Publishing Company, 1993, pp. 299–344. Accessed on 29 December via http://www.wilhelm-research.com/pdf/HW_Book_09_of_20_HiRes_v1c.pdf