There’s a scene in Cinema Paradiso that I find utterly wrenching.
The projectionist, Alfredo, has just changed the position of the projector to show a film outside against a building, since the manager has closed the theater for the night. Salvatore watches in the square below. In an instant, the image bubbles and the reel catches fire. Alfredo tries in vain to put the fire out, and is severely injured in the process, losing his sight.
Why did the reel catch fire?
Films up until the 1950s were printed on nitrate, which is a highly flammable material. It can catch fire at extremely low temperatures, and once it catches fire, it’s extremely difficult to put that fire out.

Nitrate films are, in many cases, considered hazardous materials. They are also susceptible to other kinds of deterioration. They get brittle, emit noxious gas, and bubble–eventually losing their image forever.
This material was used for films up until the 1940s or 50s. In archives, reels are often kept in cold storage to prevent decay, but because films weren’t thought worthy of preservation for many years, we have lost so many early films. According to the National Film Preservation Foundation, only 20% of feature films from the 1910s-20s still exist in complete form.
These movies are part of our cultural heritage and in my opinion they should be taken care of both in their original formats (for as long as possible) and digitized so they can be enjoyed and taken care of for years to come.
Want to see a short film that shows the nitrate degradation process? Watch Walk,–You Walk! (1912) about a couple of gals outwitting some troublesome men, which was preserved by NFPF.
Do you have nitrate films at home? My guess is no. Unless you have feature film reels (35mm), you don’t have to worry about nitrate. If you do have feature film reels, you should probably take them to a conservator or specialist. You can also learn about how to identify nitrate film here. However, 16mm and 8mm films, which is what most amateur and home film makers used, were always made on safety film (acetate). While this film type also has preservation issues (it can shrink and give off a vinegar smell and also produce channels), it’s not going to spontaneously combust.