Acid Free
Submitted by sportymale22 on November 22, 2007
Category: Science
Words: 505 | Pages: 3
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Acid-free paper is paper that has a neutral or basic pH (7 or slightly greater). It addresses the problem of preserving documents for long periods.
Paper made from wood-based pulp that has not had its lignin removed goes yellow and deteriorates over time. When exposed to light and/or heat, the molecules in the wood-pulp (or acidic) paper will break down even faster. It was only in the 1930s that the effects of wood-pulp paper became known, when William Barrow (a librarian) published a report about the deterioration of acidic paper in the libraries. For fear of the gradual disintegration of written materials, measures have been taken to improve the quality of paper.
During production, acid-free paper may be treated with a mild base (usually calcium or magnesium bicarbonate) to neutralize the natural acids occurring in wood pulp, and it may also be buffered...