Chances are, you may not recognize the objects in the photograph below. It's highly unlikely that you know the story behind them, either. But I can almost guarantee that you will never forget either the images or the story after you read the next few paragraphs.
I've worked at the San Joaquin County Historical Museum for about three and one-half years. Shortly after I arrived, one of the maintenance workers took me on a tour that included some dark, hidden corners. There we came across several canisters of film sitting quietly on a steel shelf.
"Hmm," I said to myself, "these don't belong here." So I grasped the stack and lifted it, planning to place it in a more suitable place, alongside other reels of film. This action released a cloud of foul-smelling powder, so I quickly set the containers down. Masked and gloved, we returned to the shelf and carried the stack—at arm's length—outside the Museum.
It didn't take long for us to discover what had happened.
Early in the twentieth century, most motion picture film was based on nitrate, a substance also used to make gunpowder. Over time, this kind of film can decompose, discolor, get sticky, and blister. Eventually, gooey bubbles can appear and a brown froth form that turns into fine powder—which catches fire easily. In fact, film based on nitrate has been known to ignite spontaneously.
This was the powder we smelled—a stinky, highly acidic, flammable dust that in one of its forms had already eaten through the wall of one canister.
You don't want this to happen in an archives, library, or museum, but it could have been much worse. In December 1978, construction workers at a National Archives facility filled with nitrate film accidentally started a fire with electric power tools. The flames spread quickly, destroying almost thirteen million feet of film.
Whoever accepted our reels into the Museum sometime in the distant past apparently didn't understand these dangers. Nor did they appreciate the need to keep them in a controlled environment, monitor them, and replace them with safer copies, if necessary. But we certainly know now.
Our experience with these canisters has added an entire universe of new meaning to the term explosive films, and we have learned to be much more careful.