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What is Deacidification?
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Preserving Books and Documents for Future Generations

Books and documents printed on acidic paper can weaken overtime and become brittle. Although the process is slow, the degradation of paper can eventually cause the materials to fall apart.

Today, there are many ways to preserve the information contained in books and manuscripts in new forms, including digitization. Although digitization and other reformatting processes can provide wider access to materials, it is critical to recognize the importance of the original artifact and the uncertainty and perhaps temporary nature of some of the reformatting processes.

Deacidification is the most effective method to preserve books and manuscripts in their original form, especially if materials are treated before they become brittle.

Acidic Paper

Paper has a structure composed of many layers of fiber, and has inherent suppleness and strength. However, the presence of acid in paper can cause the components of the fibers, cellulose, to degrade and the paper to become weakened as a result.

The problem of acidic paper appeared in the mass papermaking and printing manufacturing processes in the 19th century. At that time, chemically processed wood pulp became the main material for papermaking, and rosin plus aluminum sulfate were used as “sizing” for ink, preventing the ink from running. Today, the aluminum sulfate is what causes paper to become brittle.

Additionally, the paper or fiber creates various kinds of acidic substances when deterioration is advanced. As a result, the paper itself can accelerate the speed of its own decomposition.

Books at Risk for Deterioration

Aluminum sulfate, which causes paper to become brittle, was widely used in numerous western papers produced about from 1850 to 1980. Nearly all the paper manufactured during this period is acidic.

Japanese paper without aluminum sulfate, stored in appropriate conditions, can be expected to last for generations. However, Japanese paper that contains aluminum sulfate can deteriorate over time and its acidity needs to be determined.

Purpose of Deacidification

Deacidification technology neutralizes the acid harbored in paper and provides an alkaline reserve. It is a technology designed to halt the deterioration of paper caused by acid. However, it does not restore brittle paper to its original state. Deacidifying paper before it becomes brittle greatly extends its lifespan and reduces the cost of future conservation treatments.


For inquiries about the Bookkeeper deacidification process, please contact:

Preservation Technologies Japan Co.
Tel : 81 48 795 7345   Fax: 81 48 795 7346