Washing positive blueprints

I am currently treating a collection of architectural drawings and
reproductions that have been seriously damaged through long-term
improper storage.  In particular, there is a large-format positive
blueprint that is extremely brittle and acidic, badly torn along all
four edges (including areas of loss) and inconsistently faded
throughout.  In its' current condition it cannot be accessed by
researchers.  In order to make it accessible it will be necessary to
line the object.  To avoid staining, and to facilitate the lining
process, it will be necessary to wash the print.

Though Prussian Blue is insoluble in water, and somewhat resistant
to immersion, it is still standard practice to avoid washing
blueprints due to the possibility of fading.  I would be interested
in hearing from others who have washed positive blueprints in the
past and the long-term side effects it has had on the line image
itself.  Any advice would be most appreciated.

Andrea Reichert
Getty Intern in Paper Conservation
Centre Canadien d'Architecture
1920, rue Baile
Montreal, Quebec H3H 2S6
514-939-7000,  ext. 1204
Fax: 514-939-7020




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                  Conservation DistList Instance 16:33
                Distributed: Thursday, November 14, 2002
                       Message Id: cdl-16-33-021
                                  ***