Relative stability of architectural blueprints and transparencies

Emily K. Bell <ebell [at] wellesley__edu> writes writes

>These are often on very thin tracing paper, or as-yet-unidentified
>plastic films.  To me it seems that if the film is Mylar or another
>stable polyester or polyethylene film, then it will last very well,
>whereas if it is PVC or some other unstable film we might be better
>off focusing our efforts on preserving the blueprint copy instead.

You might want to keep in mind that even though polyester is a very
stable material, the media might well be very sensitive or unstable:

I once came across plastic films with a photosensitive image layer
(I don't know what type of materials exactly as there was no time
for any testing), where the emulsion showed severe signs of
deterioration after a heavy water damage; in areas where the items
were really wet, the photoreceptive coating started cockling, and
after drying, the image layer fell off in tiny flakes in these
areas, leaving a clear plastic film with no information at all...

There is an article dealing with the topic which might be useful for
you: "Permanency of reprographic images on polyester film" by Hanna
Szczepanowska, and Wayne Wilson published in AIC Vol 39 (2000) No 3,
available via

    <URL:http://cool.conservation-us.org/coolaic/jaic/articles/jaic39-03-005.html>

Anna Hoffmann
15B Clark Street
London E1 2HD


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                  Conservation DistList Instance 26:2
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