危険なフィルムの特性
Hello everyone, SCIENSPOT is a podcast that shines a spotlight on the latest scientific technology
from Japan. Your host is REN from SCIEN-TALK. Today I'll talk about the dark chemistry of early
motion pictures, exploring why the initial film stock was so dangerous and how a massive
Japanese industry effort rescued audiences and their film history itself. The base materials
for early film was commonly called celluloid, but its precise chemical name is cellulose nitrate.
This is why the film was known as nitrate film, and it was a very source of extreme danger.
Why was this chosen? Early filmmakers prioritized performance. Nitrate film offered
a superior durability and flexibility compared to early alternatives, making it ideal for the
high-speed movement required by projectors, but this performance came with a lethal trade-off.
The projectionists were not just handling visuals, they were handling what was essentially a
flammable explosive. Friction, static electricity, or even a small machine jam
in a high-temperature booth could lead instantly to a fatal fire or explosion.
Cellulose nitrate's chemistry reveals why it was so volatile. This substance has a history
of being used as a propellant or explosive. Firstly, the film was highly sensitive to heat
and friction, and a shock or friction common during high-speed projection could trigger an
explosion. Secondly, nitrate film chemically degrades over time. This degradation destabilizes
the material, giving it the potential to spontaneously ignite without an external heat
source. Film balls were accurately regarded as gunpowder magazines.
Finally, the chemical structure of nitrate film contains its own oxygen supply. Unlike common
映画上映の危険性
fires, you cannot suffocate a nitrate fire. The prescribed method required large volumes of water.
Furthermore, when burning, it releases deadly nitrogen oxides and other toxic fumes. This means
that projectionists and audiences faced not just fire but lethal gas poisoning.
These chemical realities led to tragedies such as in 1897, a fire in Paris where
screening resulted in the deaths of over 100 people. To protect audiences,
projection booths were designed as isolated, small sealed rooms. The projectionist's job
was critical. This served as a last defense responsible for containing the chemical chaos
if fire broke out. The widespread danger demanded an industrial water solution.
The shift from flammable nitrates to non-flammable safety film was a pivotal technological revolution.
In Japan, this transition was spearheaded by Fujifilm. The company received strong support
from the Japanese government, including subsidies from the Ministry of International Trade and
Industry. Fujifilm focused on mass-producing film using cellulose triacetate. Despite
major technical hurdles, the mass production technology for this material base was established
in 1952. This national effort led to the complete conversion of all films based to
cellulose triacetate base by 1958. In conclusion, RE cinema was built on the highly dangerous and
explosive chemistry of cellulose nitrate. Projectionists risked their lives daily due
to the threats of explosion, spontaneous combustion, and toxic gas release. The end
of this dangerous era was secured by a major technological effort, particularly by Fujifilm
映画産業の安全革命
in Japan, backed by the government, which successfully transitioned the industry
to safe material. The safety we now take granted in theatres is the legacy of this chemical safety
revolution, ensuring that the magic of cinema no longer comes at the cost of human life.
That's all for today's SciencePod. This podcast is broadcast in both Japanese and English.
I'd love for you to listen to the podcast and post your thoughts with the hashtag
SciencePod. Thank you for listening and see you next time.
