从19世纪下半时以来纸才获得大量生产,这之后所出版的书籍大都是使用酸性纸,在经过100年后,现在由于纸的渐渐破烂已难于保存。目前美国国会图书馆的25％、东南亚各个国家图书馆的40％和日本的图书馆的5％的书籍的纸质都已处于氧化的危险。日本国立国会图书馆对那些纸质已在不断劣化的书籍一方面 Since the second half of the 19th century, paper has been produced in large quantities. Since then, most of the books published have used acid paper. After 100 years, it is now difficult to preserve paper due to the gradual deterioration of paper. At present, 25% of the Library of Congress, 40% of libraries in countries in Southeast Asia, and 5% of books in Japanese libraries are in danger of being oxidized. The Japanese National Library of Congress