Cellulose acetate

I have begun using Bainbridge Artcare buffered sleeves (1 and 2 ply)
for cold storage of deteriorating acetate sheet photographic film.
These contain zeolites and 3.5% calcium / magnesium buffer. While
(via IPI A-D strips) it appears quite effective at absorbing acetic
acid:

    a.  Does anybody know any established limits of this material to
        absorb acetic acid?

    b.  On the understanding that acetyl groups constitute perhaps
        40%-44% of various cellulose acetate films, does anyone have
        an informed opinion as to roughly how much of this acetic
        acid needs to be given off by a film before it may be
        regarded as photographically deceased? (or is there no point
        at which this may be regarded as having happened)

James Elwing
Archives Conservator
Powerhouse Museum, Sydney


                                  ***
                  Conservation DistList Instance 15:3
                  Distributed: Thursday, June 14, 2001
                        Message Id: cdl-15-3-023
                                  ***