Preservation Department: Mass Deacidification | Yale University Library

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Preservation Department: Mass Deacidification

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Mass Deacidification

From the 1850s until the 1960s, paper was manufactured using methods that imbued it with a high acidity.  Over time this acidity causes the paper fibers to break down, thus rendering the paper brittle and causing it to crack and break.  Volumes that have already reached this stage of embrittlement can be reformatted via microfilming, photocopying, or digitization, in order to preserve their contents.  However, for volumes that are acidic but not yet brittle, there exists an efficient and cost effective technology to neutralize the acids, thus preempting this form of deterioration.

This process, known as mass deacidification, is outsourced to a vendor that utilizes a procedure which not only neutralizes the acidity of the paper, but also provides an additional non-toxic alkaline reserve, thereby significantly increasing the lifespan of the materials.

 In addition to titles acquired from countries known to still print on acidic paper, Preservation also employs mass deacidification for many materials that are treated in General Collections Conservation (GCC).  As part of the GCC workflow, the acidity of repaired volumes is tested using a pH pen.  If an item is found to be acidic and meets other physical qualifications (see Guidelines), it will be sent for mass deacidification.

For additional information regarding the process, or if you wish to initiate the treatment of a collection, please refer to the Guidelines for Selecting Materials for Mass Deacidification Projects, or contact the Preservation Services Librarian, Tara Kennedy.