Expired film doesn't have to be unpredictable and problematic. Whilst some might prefer this, it is entirely possible to preserve out of date film to be as good as new.
Undeveloped film will change over time as a gradual chemical reaction occurs. Because of this most film is sold with a best before date (process before). If you were to buy one of these expired rolls of film off the shelf in a shop you could probably expect to see a loss in contrast and colour or a variety of unexpected results.
Regardless of the process before date there are some conditions that will actually speed up the chemical reaction in the film leading to a quicker of more severe expiration. High temperatures and humidity are the two biggest concerns.
Alternatively the opposite conditions can actually help preserve your film extending its life far beyond the process by date. Try the following:
- Dry storage – keeping the film moisture free will help prolong the life of the film as the chemical reaction is minimised.
- Low temperature – keeping the film in a fridge will slow the chemical reaction and means your expired film will five excellent images for years beyond the process by date.
- Freezing – freezing takes the low temperature storage to another level and will extend the life of your film potentially for decades. Better still it can be thawed and re-frozen with no ill effects.
It’s worth mentioning that nothing lasts forever though. Even when frozen, background radiation will eventually fog the film. Deterioration may occur within ten years for example so as a rule of thumb even frozen film is best used within ten years of the expiration date.
Of course the downside to preserving film beyond its quoted expiration date is that it will always perform like new. If in fact you like to experiment with expired film and the unexpected results on offer then steer clear of the fridge-freezer.