Paper Through Time - University of Iowa

A very comprehensive and interesting research project looking at the chemical make-up and properties of historical European papers from 14th to 19th centuries. See the web-site for more - paper.lib.uiowa.edu

The primary conclusion seems to be that the higher concentration of gelatin and calcium used in earlier paper-making seems to afford better long-term protection of historical papers.

For a summary of the project, see the press release posted on ConsDist List.

(image credit - paper.lib.uiowa.edu/)