Fading blueprints

I have recently observed fading of an area of a blueprint. After
being kept in the dark for a few days, the colour was completely
restored. I would like to know if anyone has any information about
this. Does the age of the blueprint affect the fading
characteristics? Will the colour always be restored or will it
eventually remain faded? Is this a rare occurrence? Has anyone done
any research regarding the effect of light on blueprints? Finally, I
would like to read more about this effect and about blueprints in
general so any suggested resources would be appreciated. Thank you.

Belinda Fireman
Queen`s University

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                  Conservation DistList Instance 10:11
                  Distributed: Tuesday, July 16, 1996
                       Message Id: cdl-10-11-013
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