First-time visitors to the Rare Book Reading Room are often surprised by the good condition of even the oldest books in our collection. “This paper is in way better shape than the books I found in my grandparents’ house,” one patron offered. “Is it because you store these books in a vacuum-sealed vault or something?” While, yes, the Library of Congress takes its responsibility to preserve its materials very seriously and, yes, the stacks are controlled for temperature and humidity (though they are not air-sealed), the primary reason that our books have survived the centuries so well is that many were printed on paper of extremely high quality.
When you open that old book from your grandparent’s library, you might find the paper thin, yellowed, and falling apart under the touch of your hands. This brittleness resulted from a 19th century change in Western papermaking practices, when industrial paper mills, meeting the rising demand for reading material within an increasingly literate society, began using wood pulp in a cheaper, faster, mass-produced type of paper. Unfortunately, wood pulp is highly acidic, and books made from that kind of paper deteriorate over time and become borderline impossible to preserve, repair, or restore. With apologies to Quentin Tarantino, pulp fiction wasn’t made to last.
Older books, by contrast, were printed on high-quality paper made from cloth rags, not wood pulp. Beginning in the 1300s, th