Discolored paper

We have a number of 16th and 17th century German and Spanish books,
and some 18th century American books, in which some of the linen-rag
paper has turned quite brown.  It varies from page to page, does not
have "flow" lines like water-staining, is often (but not always)
darker around the text block, and is more solid than just foxing
spots.  It looks similar to turn of the 19th/20th century acidic
wood-pulp paper, but isn't homogenous throughout all the pages(or
darker on the page margins from oxidation) like when lignin damage
occurs.

The affected books were not part of any one collection prior to
their arrival at our institution so a common catastrophe or
environmental storage issue is not likely.  Summarily, the books
have been stored in moderate temperature and relatively stable, in
fact low, relative humidity since their arrival and did not all
arrive at the same time. While some of the books do indicate some
water damage this is not the case throughout.

My question therefore is two-fold.  What is the source of this
discoloration and could it pose a threat to other books stored in
the vicinity due to migration? Any suggestions or observations
anyone can provide will be much appreciated.

William L. Hopkins
Manager of Collections
American Heritage Center
University of Wyoming
Dept. 3924
1000 East University Ave.
Laramie, WY 82071
307-766-6836
Fax: 307-766-5511


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                  Conservation DistList Instance 19:23
                 Distributed: Friday, October 28, 2005
                       Message Id: cdl-19-23-027
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