Acidic Paper
Paper from several hundreds of years ago, or more, often looks newer than paper created c. 1800-1950. Why is that?
A number of factors contribute to a paper’s vulnerability. As we know, the environment in which paper is stored and how it is handled have a significant impact on its condition over time. But not all paper is created equal—a paper’s makeup and its means of production have a tremendous impact on its lifespan.
Prior to the Industrial Revolution, Western paper was produced by hand from linen or cotton rags, which generally results in a relatively durable and chemically stable paper. Around 1800, paper began to be produced with the use of machines, using wood pulp instead of rags. While these changes increased paper production dramatically, the resulting paper had an acidic chemical make-up along with a significantly shorter and weaker fiber structure. Over time, this compromised paper becomes weaker, often becoming discolored, as a result of acid degradation processes. Unfortunately, this chemical reaction is autocatalytic, meaning that it produces acid products which fuel further degradation reactions. Such paper is literally stewing in its own juices.
Fortunately, the papermaking industry has over time learned to make relatively high-quality paper using machines and wood pulp. These adaptations include the ability to process wood pulp to remove its most acidic components, and the use of affordable alkaline fillers such as calcium carbonate which contribute to creating an appealing white paper while buffering the creation of acids in the paper over time.
Beginning in the 1980s, influential standards for paper permanence were established nationally and internationally. As a result of these developments, much of the machine-made paper created in the west over the last 50 years tends to be of relatively good quality. There are many exceptions to these trends based on resources and intended use—for example, cheaper, poor-quality paper continues to be used for ephemeral applications like newspapers.
Fortunately, there are treatments that help slow down the acid degradation process. One approach that we use is a Bookkeeper® spray product that deposits minute particles onto the surface of paper that works by neutralizing many of the acids that form in the paper over time. This helps extend the lives of valuable books, newspapers and other acidic paper documents.
