Photocopy toner stability

Ann Jordan and I recently had an inquiry from Sara Tuttle at the Bertand
Museum in Iowa.  The first question concerns the stability of toner in
Cannon black and white copiers.  Apparently Cannon now uses magnetite
(rather than carbon-based) pigment because it eliminates a charging step
in the copying process.  (I had thought all "xerographic" processes used
carbon-based black pigment.)  Is magnetite as resistant to oxidation as
carbon?  Is this a real-world concern for permanence?

Second, assuming a normal (imperfect) environment, is there any reason
not to use buffered paper labels inside sealed polyethylene bags used
for now dry archaeological glass?

Please reply to me, since Sara does not have Internet access.  Thanks.

    **** Moderator's comments:   Please send replies *both* to Karen and
    to consdist [at] lindy__stanford__edu as this is of general interest.

Karen Motylewski
Northeast Document Conservation Center

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                  Conservation DistList Instance 7:57
                 Distributed: Friday, February 4, 1994
                        Message Id: cdl-7-57-004
                                  ***