|
Paper formulated with stable ingredients, which allows the paper to resist deterioration. Archival paper is used for printed documents, photographic materials, and matte boards for artwork that must remain intact for many years. Most often, the paper is composed of ingredients that have a neutral or alkaline pH. Acid-based papers deteriorate in a relatively short period of time, which is why old newspapers appear yellow and brittle. Most paper manufactured during the first half of the 20th century was made with an acid base. Paper with an alkaline base became more available in the last half of the 20th Century when the preservation of documents became much more important. Since the 1970's, most of the paper used for book publishing and other printed materials in which permanence is of importance, has been produced with an alkaline base.
|
