Although paper can be made from a wide variety of fibers, from rose petals to rice, the earliest papers produced in Europe (c. 1100-1300) were made from linen rags beaten with hammers until the fibers separated into a smooth pulp which could be mixed with water, shaped, and dried to form a sheet. Before ink could be applied, the sheets were "sized" with gelatin derived from animal hides. This sizing sealed the surface to prevent ink from being sucked from the surface into the fibers of the sheet, creating a "feathered" image on all sides and reducing legibility. This pair of materials, by lucky coincidence, were not only cheaply available, but they also produced paper that was chemically neutral or even a bit alkaline in pH. These papers, if protected from sunlight and heat and other sources of mechanical damage (insects, clumsy readers, etc.), can have shelf lives of hundreds or even thousands of years. Sun exposure causes "foxing" at the outside edges of pages, and the most commonly used pages typically are more browned and brittle than those kept tightly closed. The outside edges of most early printed books, and their initial and final pages, tend to be the most brittle. The outside leaves are the ones most commonly separated from the binding by mechanical action (i.e., readers turning these pages more often than interior pages). Nevertheless, the bulk of documents made of early papers can live amazingly long lives if protected from exterior harm, sometimes by enclosing them for storage in acid-free archival boxes or in Mylar sleeves. Papyrus scrolls protected by hot dry conditions in sand dunes covering a town dump at Oxyrinchus, Egypt (C2-3 BCE), still are the source of previously undiscovered works by classical authors like Sappho, Memander, and Callimachus, Catullus' great model. However, even if the storage conditions are controlled, everything depends upon the chemical composition of the fibers upon which the ink is laid, and the composition of the ink, itself. Even if the ink used is not acidic, the paper, itself, and its sizing, may produce acids that will destroy the document.
Papers made from even slightly acidic materials absorb water from the atmosphere and gradually become brittle as the acid eats away the fibers. "Embrittlement" first causes pages to crack at pressure points near the binding or at their outside edges. Badly embrittled books have been known to disintegrate into tiny flakes or powder. This has ominous consequences for conservation of books from about 1800 to the mid-1980s. The rapid increase in the demand for paper during the Eighteenth Century, a direct result of emergent mass literacy and a huge increase in the number and kinds of printed works produced, outstripped the supply of linen rags. Paper makers turned to wood pulp, which produces shorter fibers when pulped and also contains "lignin," a compound that resists flexing and must be reduced by chemical agents like bleaches and other compounds. Those bleaches also weakened the cellulose of which the wood-pulp fibers were composed, so the higher the lignin content of the pulp, as in cheaper papers used for newsprint, the more bleach was used to soften it and the more brittle was the resulting paper. At the same time, a rosin-alum mixture replaced gelatin in the sizing, which produced sulfuric acid on contact with water as liquid or vapor. By the late Nineteenth Century, books and newspapers were being produced with such brittle, high-acid paper that their life expectancy might be far less than a hundred years. To quote R.A. Kundrot and J.B. Zicheman of the Provenance Paper Preservation project in 2001:
"The deterioration is pandemic and losses to library and archival collections are estimated to be as high as one percent per year. Many libraries have stated that a quarter of the books in their collections are now so embrittled as to require removal from general circulation (Shahani and Wilson, 1987). Barrow (1959) predicted that most of the books of the first half of the twentieth century would not be usable in the twenty-first. A study of a major university library system indicated that fully 85% of their collections were unstable (King, 1981)."
Nineteenth-Century Anglo-American dependence on coal for heat and propulsion also led to high levels of atmospheric pollutants that attacked books when they were opened and even burned their way into the page from unprotected edges, especially from dust which accumulates on the top edges of the volume.
A general guide to publication dates which should make the researcher suspect the presence of chemically processed wood-pulp papers is offered by Williams and Abbott: "it is known when certain ingredients were introduced in papermaking: for instance, soda wood pulp in 1845, mechanical wood pulp in 1869, esparto grass in 1861, chemically pulped wood in 1874, rosin in 1835, clay filler in 1870" (13). Documents produced before 1835 may be more flexible than those produced after that year, and those produced after the 1870s and before the mid-1980s may be the most at risk. Researchers who encounter books whose pages are not easily flexible, are flaking significantly, or are in danger of imminent destruction, should succinctly record the extent of the damage by pages and page-area, and documents which appear to be at serious risk should be reported to the Special Collections librarian.
Generally, of course, researchers should handle all documents in Rare Books collections with great care. Use pads or "pillows" to keep the book from opening flat on a table, which cracks and degrades the binding. Turn pages carefully, trying to avoid brittle edges and corners. Keep all loose pages exactly in the order and orientation (up-down/left-right) orientation in which they first appear unless a previous researcher appears to have disordered them. (Consult the SC librarian for advice.) Return all documents not currently in use to any protective archival boxes or Mylar sleeves to limit accidental damage, and notify the SC librarian when you are done using them so that they can be re-shelved promptly.
Works Cited and Consulted
Kundrot, R.A. and J. B. Zicherman, “Paper Permanence,” in The Encyclopedia of Materials: Science and Technology. (Elsevier Science, 2001) Available online at http://www.provenance.ws/Paper%20Permanence.htm Viewed 2/13/06.
McKerrow, R.B. An Introduction to Bibliography for Literary Students. (Oxford: Clarendon, 1927, rpt. with corrections, 1928). Pp. 100-105.
POxy [The Oxford Papyrology Site: Oxyrinchus]. Available online at: http://www.papyrology.ox.ac.uk/POxy/ Viewed 2/13/06.
Williams, William Proctor and Craig S. Abbott. An Introduction to Bibliographical and Textual Studies. Second Edition. N.Y.: Modern Language Association, 1989. Pp. 13-14.