Humidification of blueprints, bluelines, brownline prints

In the process of studying color changes on whiteprints due to the
application of hinges on the reverse, I found that the dye-layer on most
"blueprint" type materials is highly water soluble.  This may extend to
the bleeding of dye from areas of blue to white under conditions of high
humidity.  This was not the subject of the study so I can not give a
definitive answer, but I can attest to the highly mobile nature of the
developed and undeveloped dye in the presence to liquid water.

Whiteprints have a white background with blue lines and solid areas.
Blueprints have blue background with white lines.  There are also
similar materials with magenta, red and black dyes.

Tim Vitale
158 Via Trinita
Aptos, CA 95003
408-684-2731
Fax: 684-1847

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                  Conservation DistList Instance 8:55
                Distributed: Wednesday, January 18, 1995
                        Message Id: cdl-8-55-002
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