What Happens When Film Gets Old?
For over 100 years, photographic film was the method for taking pictures. You couldn’t do it without film until digital arrived. While the technology of digital has surpassed film in some terms of quality, there is still a look with film that digital does not have. This is why so many people are going back to film, if not permanently, at least as a tool for disciplining their work and finding that “look” that they want.
We often get old film, and people ask “How old is too old to use film?” or “How do I know old film is good?” So, what actually happens when film gets old?
As film ages, it is effected by several factors that will accelerate its aging: heat, humidity, radiation, and chemicals in the air will all degrade the film. The worst by far are heat and radiation.
Heat. Heat affects film by making it more susceptible to damage from radiation. Excessive heat “bakes” the film so that it does not respond to light the way it was intended. Hot film is more sensitive to the normal background radiation that we are exposed to every day.
Radiation. Cosmic rays, old TVs and certain old electronic devices emit X-rays that will cause the film to be fogged. Fogging is where the whole film is slightly to greatly exposed so that when the image is exposed on the film, there is very little range left for the film to capture. All exposures are additive, so a little will be expected , but a lot may mean that nothing can come out since the fogging has used up all of the exposure range. Sometimes we process old film and it looks blank, but it is also very dark, since the fogging on the base was so great everything else was covered up.
Here are 2 control strips that we use to monitor our film processor. The one on the left was intentionally left in a car for quite a while this summer, in the heat, and it shows heat damage – fogging. The one on the right was kept in optimal cold storage and has no fogging. The patches running up the middle tell the tale. As you can see, the D-minimum area ( patch D to the left) is very dark on the left, and is not even visible as on the right hand control strip. The level of base fog makes the darkest areas on the left side grey, not black. So a portion of the range of details is gone. As the film gets more damaged, the number of patches will disappear and eventually all the details will be gone. In the mean time the colors will skew and loose their vibrancy and accuracy as the different layers are damaged. You can see this from D, C and B; but also look at A. This is the D-Maximum – this is the white areas. As the black areas are disappearing because the base fog is getting darker, the white areas are also getting exposure, so they too are darker and harder to get detail from.
What happens to Polaroid and Impossible films?
These films are unique in that they are completely self contained; they have both processing chemicals and a battery in the pack. This makes them that much more sensitive to external forces. The packs best kept cool, dry and dark. Excessive heat will fog the film, rendering the image more and more gray and the excessive exposure will eventually turning the whole picture white with excess fogging. (This is the opposite of negative film because these pack films make positive pictures, with no negative). Excessive heat can dry out the chemical pod and cause the battery to deplete earlier. Some airborne chemicals can effect how the film develops, but this is most likely not a home situation. Light may cause these packs of film to be exposed on the sides and corners if they are removed from the foil package and left out in the light.
What is the best way to store films? Cool, dry, dark.
Cool- between 45 and 55 degrees F is optimal. Freezing can and will damage the Impossible and Polaroid films, as well as increase the sensitivity of certain films like black and white film so it fogs faster.
Dry- excessive humidity in the air will cause the emulsion to stick to itself and damage the film, or not allow the pack films to eject.
Dark- because film is sensitive to light and radiation, any thing that keeps it dark will minimize the effects of stray light or even X-rays. Minimal, yes, but every little bit helps.