Identifying photocopy method

Joselle Merritt-Dennis <joey0615 [at] pacbell__net> writes

>I am currently doing an internship at the Graduate Theological Union
>in Berkeley.  I am an MLIS student at SJSU. I have found a folder of
>copies on a very strange paper.  The archivist here has never seen
>them before either. They appear to be copies of a journal by
>Phinneas Quimby (mid-1800's).
>
>The copies were probably made in the 1970's (?).  They are darkening
>evenly and appear to have a very thin layer of what looks like
>tin-foil in the center of the paper.  I can tell because when the
>corners bend or tear or the sheets are scraped the metal shows
>through.  On both sides of this metal layer is paper.  What is this
>copy paper that these copies been made on and what is the best way
>of preserving it.

I have seen an example of this copy type. The example was a copy of
an engineering drawing and had faded out to almost nothing. I am
unsure of the copy method--none of my extensive reading on this
subject has revealed any clues. A possibility is that it is a
thermal method and the foil layer acts as a sort of reflector.
Another possibility is that the copy method is electrostatic and
uses differential electrical charging (eg Electrofax or Xerox) and
that the foil somehow facilitates the copying process.

Whatever the answer, the copies are very fugitive and should be
copied as soon as possible.

    **** Moderator's comments: See also related query in this
    Instance.

Ian Batterham
Assistant Director, Preservation
National Archives of Australia
PO Box 7425,
Canberra Mail Centre
ACT  2610
Australia
+61 2 62123424
Fax: +61 2 62416772


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                  Conservation DistList Instance 16:4
                  Distributed: Wednesday, July 3, 2002
                        Message Id: cdl-16-4-004
                                  ***