General information


Deacidification: A term generally considered to mean the removal of acid from, or the reduction of the acidity in, a material, such as paper. The usual process of deacidification is to treat the paper with a mild alkali which initially neutralizes any acid present and is then converted into a compound that remains in the fibers of the paper to act as a buffer to neutralize any further acidity that may develop (usually as a result of exposure of the paper to atmospheric sulfer dioxide).
Roberts, Matt and Don Etherington. Bookbinding and the Conservation of books: A Dictionary of Descriptive Terminology. Washington, D.C.: Library of Congress, 1982. Online edition (Walter Henry, ed., 1994) (accessed August 26, 2014).

Deacidification is a treatment used to prevent/arrest the brittling of acidic pages. It is a preventative treatment and will not strengthen already crumbling paper. Selection criteria usually involve determining if the item is acidic, if it is still strong enough to withstand treatment, and if it is something that is desirable to be kept in its printed format.

There are two basic types of treatment: aqueous and non-aqueous. Aqueous deacidification involves bathing individual pages in an alkaline water solution. This time- and labor-intensive process is usually done by conservators, and is outside the needs of most institutional preservation programs. Non-aqueous deacidification is the process of deacidifying bound items in an alternative carrier that does not present the problems that water does. Bound items can be treated in quantity, hence the term “mass deacidification.” This method is provided through vendors and commercial products. Since mass deacidification is what the average librarian is likely to deal with, that is the focus of our discussion.


There are no official standards that determine how something should be deacidified and what the results should be. However, materials treated by the different commercial processes available have been tested for compliance with general standards such as paper permanence, performance, and photo-activity. Many of these results are found in the resources listed below, and individual vendors will usually supply test results. In the United States, the requirements established for the deacidification program at the Library of Congress are often used by other institutions.


The Mass Deacidification site at the Conservation Online webpage at Stanford
A well-regarded clearinghouse for conservation and preservation information. Includes many studies and a bibliography of mass deacidification.

The Library of Congress’ site on mass deacidification
Includes their studies/standards, current program, and bibliography.

The National Archives Conference on mass deacidification
Describes current position regarding deacidification.

Presentation at IFLA on mass deacidification


Current businesses that provide mass deacidification services or products. Sites often include research, chemical characteristics, facility and process tours, customer lists, and other valuable information. These listings are given as resources for information about various chemistries, processes, and testing results only available through the vendors themselves. This listing does not imply endorsement by the Preservation Committee of the Music Library Association or the Music Library Association at large.

Preservation Technologies (US)


Sequeira, S., C. Casanova and E.J. Cabrita. “Deacidification of paper

using dispersions of Ca(OH)2 nanoparticles in isopropanol: Study of efficiency.” Journal of Cultural Heritage 7 (2006): 264–272.

Issues with treating music

Generally, the qualities that differentiate scores from other printed materials (content, size) have no bearing on their suitability for deacidificiation. Considerations are as follows:

  1. Non-standard sizes of music scores: When outsourcing deacidification work, make sure that the different sizes of scores can be accommodated. Price may then vary.
  2. Parts: When outsourcing, discuss how parts will be treated and kept together.
  3. Ozalid or diazo scores: This process of reproducing scores is similar to blueprints, which is a pH sensitive chemical process. Since the process of deacidification changes the pH, it is not recommended for these types of materials. The following resource may assist in identifying Ozalid/diazo prints:
Reed, Judith, Eléonore Kissel, and Erin Vigneau. “Photo-Reproductive Processes
Used for the Duplication of Architectural and Engineering Drawings: Creating Guidelines for Identification.” Book and Paper Group Annual, American Institute for Conservation. 14 (1995).

Music-specific resources

Carli, Alice. The Binding and Care of Printed Music. Lantham, MD: Scarecrow Press,


This book is currently the only resource that specifically addresses the deacidification of music. It details the adaptation of a deacidification program at the Sibley Library at the Eastman School of Music, and gives specifics on implementation of the plan.

Many other libraries have used mass deacidification services to treat music. Searching the archives of the mailing list of the Music Library Association is one way of monitoring the experiences of various libraries:

Originally compiled by Lisa Lazar, deacidification.
Last updated: August 26, 2014, at 10:54 AM EDT

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