Mass deacidification

Mass deacidification is a term used in Library and Information Science for one possible measure against the degradation of paper in old books (the so-called "slow fires"). The goal of the process is to increase the pH of acidic paper on a large scale. Although acid-free paper has become more common, a large body of acidic paper still exists in books made after the 1850s because of its cheaper and simpler production methods. Acidic paper, especially when exposed to light, air pollution, or high relative humidity, yellows and becomes brittle over time. During mass deacidification an alkaline agent is deposited in the paper to neutralize existing acid and prevent further decay.