Thanks Bill for these clarifications. I'll take a look at the article. Best, Andy
On Aug 23, 2008, at 7:20 PM, Bill Burns wrote: > 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 > _______________________________________________ > Phono-L mailing list > http://phono-l.oldcrank.org
