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1.1 This guide covers offset and book papers, both coated and uncoated, used in the preparation of permanent records. Permanent records usually are expected to last several hundred years in a records repository, with little change in properties that affect readibility or handling, although some records are expected to have shorter lifetimes.

1.2 Acidic materials incorporated in paper during manufacture (for example, rosin-alum sizing) contribute to deterioration. It has been shown (1, 2, 3, 4, 5) that the life expectancy of uncoated papers is an approximate function of the pH of an aqueous extract of the paper.

1.3 The following would be expected to contribute significantly to the life expectancy of books and documents: the use of papers with controlled acidity or of papers manufactured under neutral or alkaline conditions, especially papers with a calcium carbonate filler that absorbs acidic gases from the atmosphere or can neutralize acidic materials formed in the aging of paper.

1.4 Three pH levels reflecting three levels of life expectancy are outlined in this guide. As one cannot rely on pH alone as an indicator of stability, minimum retentions of properties after accelerated aging at 90

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Published: 01/01/1996 Number of Pages: 9File Size: 1 file , 48 KB