[Phono-L] Kinetoscope film inquiry Value?

[Bill Burns]

ClockworkHome at aol.com wrote:

> Some of the films were on nitrate film stock rather than acetate 
> safety film. Any old film that has a smell of vinegar usually means
> that it is nitrate and becoming unstable.

This isn't quite right; it's *acetate* film that smells of vinegar.

Three bases have been used for film, in historical order:

Cellulose Nitrate: Highly flammable. On decomposition it produces nitric 
oxide, nitrogen dioxide, and other gases, which may be irritating to the 
eyes, nose, and throat.  Does *not* smell of vinegar.

Cellulose Acetate: Not particularly flammable, produces acetic acid as
it decomposes (hence the vinegar smell); the film base also shrinks and
wrinkles.

Polyester: The modern base, strong and stable.

This Wikpedia article gives much more detail:

http://en.wikipedia.org/wiki/Film_base

-- 
Bill Burns
Long Island   NY   USA
http://ftldesign.com