A film can provides a high degree of physical protection to the film, enables safe handing during transport and provides a large amount of area to place identification information.
Film cans must be manufactured from photographically “safe” materials. The metal used is commonly steel or aluminium. Painted cans should not be used unless the type of paint is known to be safe for long term storage with photographic materials. Some film manufacturer’s film cans have an internal coating, this is acceptable. Plastic or polymer film cans should be made from polymers identified in the most current version of ISO 18902 Imaging Materials – Processed photographic films, plates and paper – Filing enclosures and storage containers.
There are two broad categories of film can design, vented and non-vented. There is some evidence that vented cans may retard the rate of decomposition in cellulose ester based films under some storage conditions. 1
1 M. Newnham, Vented Film Cans – Their Effect on the Diffusion of Decomposition By-products from Motion Picture Film, SMPTE Journal January 2002, pp29-33