n.a preservation technique used en masse to increase the longevity of paper documents by raising the pH to at least 7.0 and often includes depositing an alkaline buffering agent on the surfaceBurke 1983, 296 The National Archives is joining the Library of Congress in mass deacidification experiments.Cunha 1990, 199Mass deacidification. In the last ten years there has been much research and development in many areas of conservation, but nothing has been as dramatic as the development in mass deacidification. Not too long ago the problem of salvaging acid-stained and brittle paper seemed hopeless, and custodians were resigned to reliance on microforms for saving the information on brittle paper. During the 1970s there were several well-established methods for deacidification of single sheets, but none was suitable for the simultaneous treatment of large quantities of paper. However, there emerged in the scientific community a belief that the many hundreds of millions of embrittled books and paper records in libraries and archives could be saved.Cunha 1990, 200Mass deacidification is primarily useful for new or nearly new materials in which acid damage has not made them fragile. Mass deacidification has been a great step forward but there remains a need for a mass treatment that will deacidify and simultaneously (or within the same run or cycle) strengthen acid-damaged paper that has deteriorated beyond the point where deacidification alone is sufficient.Grimard 1994, 679In spite of the limitations indicated here, the National Archives of Canada experiment has provided interesting results about the viability of mass deacidification processes and has extended the life of half a million books. This is no small contribution.Harris and Shahani 1994 Over the past two decades, the Library of Congress has been at the forefront of the development of deacidification processes that can be applied en masse to large collections. In its search for an ideal mass deacidification process, the Library invented and further developed the diethyl zinc (DEZ) gaseous process and also brought about key improvements in solvent-based, liquid phase processes. In the conservation science community, gaseous processes have traditionally been deemed to have a significant edge over liquid phase, solvent-based processes, mainly because they preclude any possibility of adverse effects on inks, dyes and colored pigments in manuscripts, color plates and book covers due to bleeding or softening of inks.Porck and Teygeler 2000, 46Although mass deacidification has been incorporated into general conservation practice, the treatment criteria remain uncertain. In addition to the lack of standardized procedures to evaluate the effectiveness and efficiency of the deacidification treatment, an important question is how much alkaline reserve is needed in the paper.Ritzenthaler 2010, 353, fn. 14For this reason, libraries planning mass deacidification programs for books focus on materials whose paper retains some degree of folding endurance or strength.
