Inhibitory Effect of Bakusho (airing of books) on Acidifying Chinese Books Paper

Abstract

Book paper pH of Chinese books published in the Qing Dynasty era was 5.3 for Senshi, however, 4.0 and 3.8 for bamboo and wood pulp paper, respectively. Book airing was supposed to have an effect on nonacidification of Chinese books by volatilizing organic acids and this effect was examined. A mock-up book comprised of bamboo paper was subjected to the dry heat treatment for decreasing pH, and Bakusho to confirm the pH recovery effect. This study aims to establish the method of conserving acidifying real Chinese books. First, the influence of air pollution was examined for real Chinese books. And, Bakusho was carried out to Chinese books in University of Tsukuba Library and the resulting pH change was determined to evaluate the Bakusho procedure and effect. pH of once acidified Chinese books was effectively recovered by 0.3 to 0.5. Consequently, exposing books in a place with sufficient ventilation of air for more than 24 hours is appropriate and directing an air flow to books has an additional effect.