In article <[log in to unmask]>,
"Carley R. Robison" <[log in to unmask]> wrote:

> I am dealing with some blueprints too and know enough to know nothing.
> What is the name of the photographic process?  They're not cyanotypes ---
> really? Are they?  I thought I'd try to describe the process because some
> of what we have are blueprints that aren't blue.

For more information on "blueprints", including the ones that are not
blue, check the following on Conservation Online (Stanford U.):

   http://palimpsest.stanford.edu/bytopic/repro/nadeau1.txt

This is mostly about office reprographic processes but much of it applies
to "blueprints"

They'd be best handled by a photo conservator, but basically, the real
blueprints (ferroprussiate process or ferric-ferrocyanide process) are
sensitive to an alkaline environment. You should avoid buffered envelopes,
etc.

Luis Nadeau

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Fredericton, New Brunswick, Canada
http://www.mi.net/dialin/awef6t/
http://www.primenet.com/~dbarto/lnadeau.html