Deacidification
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Mass deacidification is a term used in
library and information science Library and information science (LIS)Library and Information Sciences is the name used in the Dewey Decimal Classification for class 20 from the 18th edition (1971) to the 22nd edition (2003). are two interconnected disciplines that deal with inf ...
as one possible measure against the degradation of
paper Paper is a thin sheet material produced by mechanically or chemically processing cellulose fibres derived from wood, Textile, rags, poaceae, grasses, Feces#Other uses, herbivore dung, or other vegetable sources in water. Once the water is dra ...
in old
book A book is a structured presentation of recorded information, primarily verbal and graphical, through a medium. Originally physical, electronic books and audiobooks are now existent. Physical books are objects that contain printed material, ...
s, the so-called " slow fires". The goal of the process is to increase the pH of acidic paper. Although
acid-free paper Acid-free paper is paper that, if infused in water, yields a neutral or basic pH (7 or slightly greater). It can be made from any cellulose fiber as long as the active acid pulp is eliminated during processing. It is also lignin- and sulfur-fr ...
has become more common, a large body of acidic paper still exists in books made after the 1850s; this is because of its cheaper and simpler production methods. Acidic paper, especially when exposed to
light Light, visible light, or visible radiation is electromagnetic radiation that can be visual perception, perceived by the human eye. Visible light spans the visible spectrum and is usually defined as having wavelengths in the range of 400– ...
,
air pollution Air pollution is the presence of substances in the Atmosphere of Earth, air that are harmful to humans, other living beings or the environment. Pollutants can be Gas, gases like Ground-level ozone, ozone or nitrogen oxides or small particles li ...
, or high
relative humidity Humidity is the concentration of water vapor present in the air. Water vapor, the gaseous state of water, is generally invisible to the human eye. Humidity indicates the likelihood for precipitation (meteorology), precipitation, dew, or fog t ...
, yellows and becomes brittle over time. During mass deacidification an
alkaline In chemistry, an alkali (; from the Arabic word , ) is a basic salt of an alkali metal or an alkaline earth metal. An alkali can also be defined as a base that dissolves in water. A solution of a soluble base has a pH greater than 7.0. The ...
agent is deposited in the paper to neutralize existing acid and prevent further decay. Mass deacidification is intended for objects on acidic paper that will be lost if no action is performed.


History of research and process development

Mass deacidification—along with
microfilm A microform is a scaled-down reproduction of a document, typically either photographic film or paper, made for the purposes of transmission, storage, reading, and printing. Microform images are commonly reduced to about 4% or of the original d ...
and lamination—was developed during the early and mid-20th century as a response to the chemical process of
hydrolysis Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution reaction, substitution, elimination reaction, elimination, and solvation reactions in which water ...
by which the fibers that constitute paper, providing its structure and strength, have their bonds broken, resulting in paper that becomes increasingly brittle over time. Environmental pollutants can react with paper to form acids that promote oxidation, creating more acid as a by-product, which results in a positive feedback loop of autocatalytic destruction. Supported in part by grants from the Council on Library Resources, William J. Barrow conducted research into paper decay and found that no more than three percent of books published between 1900 and 1949 would survive more than fifty years. In response to this, a Standing Committee on the Preservation of Research Library Materials was formed by the Association of Research Libraries (ARL) in 1960. Barrow also invented an aqueous process to neutralize acid in paper while depositing an alkaline buffer that would slow the rate of decay.Ritzenthaler, M. (1993). ''Preserving Archives and Manuscripts'' In addition to Barrow's original method, both non-aqueous—employing organic solvents—and vaporous—the Library of Congress' DEZ (diethyl zinc) treatment—methods of achieving the same results have been researched in an attempt to reduce time, labor, and cost requirements.Pillete, R. (2003)
Mass Deacidification: A Preservation Option for Libraries
''World Library and Information Congress: 69th IFLA General Conference and Council''. URL accessed April 28, 2008.
One technique proposed is to place books in an evacuated chamber, then introduce diethylzinc (DEZ). In theory, the diethylzinc would react with acidic residues in the paper, leaving an alkaline residue that would protect the paper against further degradation. In practice, the heating required to remove trace water from the books before reaction (DEZ reacts violently with water) caused an accelerated degradation of the paper, a series of chemical reactions between DEZ and other components of the book (glues, bindings), caused further damage, and produced unpleasant aromas. In the 1980s, a pilot plant for mass deacidification, using this process, was constructed by
NASA The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the federal government of the United States, US federal government responsible for the United States ...
and was tested on books provided by the Library of Congress. In 1986 it was discovered that the DEZ had not been removed in one of the deacidification runs and pooled in the bottom of the chamber, possibly remaining within the plumbing. DEZ is violently flammable when it comes in contact with either oxygen or water vapor, so the vacuum chamber could not be opened to remove the books within. Eventually, explosives were used to rupture the suspect plumbing; suspicions of the presence of residual DEZ were confirmed by the subsequent fire that destroyed the plant. In his book '' Double Fold'',
Nicholson Baker Nicholson Baker (born January 7, 1957) is an American novelist and essayist. His fiction generally de-emphasizes narrative in favor of careful description and characterization. His early novels such as ''The Mezzanine'' and ''Room Temperature ( ...
discusses the failure of the NASA program at great length. The chemical company
AkzoNobel Akzo Nobel N.V., stylised as AkzoNobel, is a Dutch multinational corporation, multinational company which creates paints and performance coatings for both industry and consumers worldwide. Headquartered in Amsterdam, the company has activities ...
made later attempts at refining the process. The risks of fire and explosions were reduced by a better process design, however, damage and odors remained a problem. In the end, AkzoNobel determined the process was not a viable commercial proposition and shut down their research at the end of 1994.


Goals

These are the results that the
Library of Congress The Library of Congress (LOC) is a research library in Washington, D.C., serving as the library and research service for the United States Congress and the ''de facto'' national library of the United States. It also administers Copyright law o ...
expected of an ideal mass deacidification treatment in 1994: *neutralize acidic paper and add an alkaline reserve. *produce a pH value between 6.8 and 10.4 that is evenly distributed throughout the book. *should not cause any damage to adhesives, inks, or dyes. *should not cause an odor or any change in the color of the paper. *should not cause loss of pliancy or mechanical strength.Library of Congress. (1994)

URL accessed April 5th,2022.
Faculty members of the Slovak University of Technology in Bratislava, Slovak University of Technology added these further requirements: *the chemicals used have to be safe. *the process has to be able to be applied to any kind of paper. *the process can not cause swelling or warping of the paper.


Effects

All of the processes imparted an adequately high pH in studies conducted by the European Commission on Preservation and Access, the Library of Congress, and a team of scientists from the Centre de Recherches sur la Conservation des Documents Graphiques in the early and mid-nineties. BookKeeper produced a pH of 9–10. CSC Book Saver yielded a pH of 8.78–10.5. Wei T'o gives 7.5 to 10.4, and Papersave gives a pH of 7.5–9. The same studies also found that the processes had adverse cosmetic side effects. BookKeeper left "a palpable residue", clamp marks on the covers, and caused some of the colored inks to rub off. CSC Book Saver left a "white powdery deposit" on books. Papersave caused "discoloration, white deposit, Newton's rings, bleeding of inks and dyes, odor and different 'feel' of the paper." Wei T'o caused "odor, white residues, rings, cockling, (yellow) discolorations and adhesive bleeding." Conservators from the British Library acknowledge that the existing mass deacidification processes are still being developed and further research needs to be conducted on their chemical and mechanical effects.


Services

Several commercial deacidification techniques are on the market : *The BookKeeper process is a non-aqueous, liquid phase process that uses
magnesium oxide Magnesium oxide (MgO), or magnesia, is a white hygroscopic solid mineral that occurs naturally as periclase and is a source of magnesium (see also oxide). It has an empirical formula of MgO and consists of a lattice of Mg2+ ions and O2− ions ...
. BookKeeper is available through Preservation Technologies, L.P. with plants in the U.S., Spain, Japan, Poland, The Netherlands, South Africa, Qatar. Another plant is available through Fratielivi in Italy. *The CSC Book Saver uses carbonated magnesium propylate for deacidification.Banik, G. (2003). Mass deacidification technology in Germany and its Quality Control. ''Restaurator: International Journal for the Preservation of Library and Archival Material'',26, 64. The CSC Book Saver is available in Europe through Conservación de Sustratos Celulósicos S.L. (CSC) (Barcelona, Spain). *The Papersave process was developed by Battelle Ingenieurtechnik GmbH and is, therefore, sometimes referred to as "the Battelle Process". The process uses magnesium titanium alkoxide. The Papersave process is available in Europe through Nitrochemie Wimmis (Wimmis, Switzerland) under the name of Papersave Swiss and the Zentrum für Bucherhaltung (Leipzig, Germany). *The Wei T'o process uses methoxy magnesium methyl carbonate, or isopropoxy magnesium isopropyl carbonate,Porck, H. (1996). Mass deacidification. An update of possibilities and limitations
Wei T'o and Sable
. URL accessed October 5, 2007.
and new products are coming out in 2008. Wei T'o is less commonly used for mass deacidification treatment than for single item deacidification. Wei T'o products are available through Wei T'o Associates Inc. (Matteson, US). BookKeeper, CSC Booksaver, Papersave, and Wei T'o are also available as hand-held sprays.


Adoption and costs

While deacidification has been adopted by major research libraries such as the Library of Congress and the New York Public Library, it is not clear whether many archives, particularly those in the United States, have followed suit. Some European national archives have tested deacidification techniques. The United States'
National Archives and Records Administration The National Archives and Records Administration (NARA) is an independent agency of the United States government within the executive branch, charged with the preservation and documentation of government and historical records. It is also task ...
(NARA), which pioneered an aqueous technique that improved upon Barrow's, chose to invest its preservation dollars elsewhere. In 2000, the Chief of the NARA Document Conservation Laboratory defended the lack of a mass deacidification program by pointing to differences between library and archival collections. For example, noting that many of the papers coming to NARA were of a higher quality than those in library collections; that the Archives does not receive records from federal government agencies until they are at least 30 years old, by which time acidic paper will have already been irrevocably weakened, and that limited resources might best be applied elsewhere, such as climate control. Under the Archives' Twenty-Year Preservation Plan, emphasis was placed on achieving the "maximum benefit for the greatest number of records." Though now dated, several sources estimate the costs and suitability of deacidification treatment. Studies conducted by the Harry Ransom Humanities Research Center and the General State Archive of the Netherlands found the DEZ method might be particularly applicable to archival materials. It was estimated that deacidification costs, excluding transportation and handling, during the early 1990s was $5–10 per volume. During 1995–1997, the Library of Congress received $2 million in appropriations to deacidify 72,000 books using the Bookkeeper commercial method and evaluate alternative methods. The actual cost per book was $11.70. Finally, a 2003 cost comparison with reformatting options per volume yielded $125 for microfilming, $50 for scanning and minimal indexing and, based on a New York Public Library project, $16.20 for deacidification. However, already in 2004
Google Books Google Books (previously known as Google Book Search, Google Print, and by its code-name Project Ocean) is a service from Google that searches the full text of books and magazines that Google has scanned, converted to text using optical charac ...
was able to scan for only $10-$20 per book. As of 2022, there were five mass deacidification plants in the world.


See also

*
Preservation (library and archive) In conservation, library and archival science, preservation is a set of preventive conservation activities aimed at prolonging the life of a record, book, or object while making as few changes as possible. Preservation activities vary widely an ...
* '' Double Fold'' *
Paper Paper is a thin sheet material produced by mechanically or chemically processing cellulose fibres derived from wood, Textile, rags, poaceae, grasses, Feces#Other uses, herbivore dung, or other vegetable sources in water. Once the water is dra ...
*
Pulp (paper) Pulp is a fibrous Lignocellulosic biomass, lignocellulosic material prepared by chemically, semi-chemically, or mechanically isolating the cellulose fiber, cellulosic fibers of wood, fiber crops, Paper recycling, waste paper, or cotton paper, rag ...
* Preservation survey *
Foxing Foxing is an age-related process of deterioration that causes spots and browning on paper documents such as books, postage stamps, old paper money and certificates, and on textiles such as clothing and artists' canvasses. The name may be a var ...
* Rare Books and Manuscripts Section *
Paper Chemicals Paper chemicals designate a group of Chemical substance, chemicals that are used for Papermaking, paper manufacturing, or modify the properties of paper. These chemicals can be used to alter the paper in many ways, including changing its color and ...


References


External links


The Library of Congress' links to Mass Deacidification Publications

The Canadian Conservation Institute's study on Evaluating Commercial Deacidification Processes


{{DEFAULTSORT:Mass deacidification Preservation (library and archival science) Paper Chemical processes