Three out of every four books in Europe's libraries are printed on acidic paper that isn't expected to last another century. That's the message heard by delegates at the IUPAC World Chemistry Congress in Turin, Italy, this week, who were asked: can analytical chemistry rescue our written heritage?
These, the first sentences in this report, Can Chemistry Save Our Libraries , certainly caught my attention.
It's books made between around 1860 and 1990 that are the real concern, said Strlic [Matija Strlic, from the University of Ljubljana, Slovenia,] - and these are the books that make up the bulk of most library collections. Before 1850 or so, paper was made by hand from clothing rags. This gave a paper with high quality fibres and neutral pH, which is expected to last several millennia. But once paper making was industrialised, the sheets made by the new process were of pH 4 to 5. Left untreated, this paper will only survive a couple of hundred years before disintegrating, due to gradual depolymerisation of the cellulose fibres caused by the acid.
The article discusses a project called SurveNIR and the development of a near infrared (NIR) technique to assess whether or not a book needs to be mass-deacidified by checking to see, first of all, if it actually needs the process done, and secondly, whether it's strong enough to withstand it. Unlike the process used now, it leaves the paper completely unmarked.
Jan Wouters, of the Royal Institute for Cultural Heritage in Brussels, Belgium, presented a related talk,discussing how each page of a valuable 8th century illuminated manuscript, the Codex Eyckensis, was laminated by conservators in the 1950s. The lamination not only affected the look and feel of the manuscript, it also accelerated the decay of the parchment and had to be laboriously removed.
Determining how any preservation treatment will affect an artifact, said Strlic, assessing both short and long-term effects, can be done now using model paper aging.
It's particularly important not to use new techniques on the most precious books before they are fully tested, he said.
