Advances in chemistry are helping to preserve old books for future generations, a valuable process that is needed in the days when the printed word seems to be disappearing. Kalpana Sharma investigates…
We are all living in the 21st Century, where most commercials sectors, including publishing, have embraced technology. Digital culture is spreading quickly and is saving crumbling books by turning them into e-books. But did you know that chemistry is also saving millions of books?
Many years ago, before the invention of paper in China, papyrus, clay, wood, stone and animal skins were used to write on. In the 15th Century, Gutenberg’s printing press brought revolution, and the book industry flourished by producing books on religion, science, technology, art and more. The paper that people were using for print was produced most economically by using wood pulp.
Wood pulp is processed to make paper either mechanically or chemically. Paper made out of wood pulp reacts with heat, light and moisture and this produces acids. These acids react in turn with paper and give the paper a yellowish, crumbly texture. Gradually, the pages of the books begin to deteriorate and, with rare books in particular, there is the risk of losing the knowledge those books hold.
In many public libraries, many old books are quietly disintegrating between their covers because, even in the best environmental conditions, paper still releases these harmful acids. But, chemistry is competing with digitization to provide a cure: ‘De acidification’ or ‘Neutralizing the acids’.
Books can be treated chemically to neutralize the acids and stop the deterioration. The pages of the books can be immersed in an alkaline solution or this solution can be sprayed onto the pages. It does not harm the book cover or the bindings. A much more effective treatment is to plunge the books into Diethyl zinc solution (DEZ). It produces solid zinc oxide, which deposits itself in the cellulose and wood fibres. As a basic oxide, it neutralizes the acids. In US, the government has designed a new DEZ treatment plant, where as many as 9000 books can be treated at once to neutralize the acids.
Whether its chemistry of digitization which ultimately preserves the knowledge contained in rare books, what is important is that books at risk are identified so that they can be treated by either (or both!) methods.
Image Courtesy of Richard Cahan