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Acidic paper is paper which was manufactured using acidic substances. [1] Widely used since the mid-nineteenth century, its pages become yellow within years, extremely brittle over decades, and eventually unreadable in the library and archive collections intended to preserve them. [ 2 ]
The company Hercules Incorporated developed the first alkaline sizing in the 1950s that made acid-free paper possible. [10] Despite the advances in paper making and the identification of and concern around the brittle book problem, it took decades before the adoption of ANSI NISO Standard Z39.48-1984 - Permanence of Paper for Publications and Documents in Libraries in 1984.
Stop bath is an acidic solution used for processing black-and-white photographic films, plates, and paper. It is used to neutralize the alkaline developer, thus halting development. [1] Stop bath is commonly a 2% dilution of acetic acid in water, though a 2.5% solution of potassium or sodium metabisulfite works just as well. [1]
Although acid-free paper has become more common, a large body of acidic paper still exists in books made after the 1850s; this is because of its cheaper and simpler production methods. Acidic paper, especially when exposed to light, air pollution, or high relative humidity, yellows and becomes brittle over time. [1]
The primary preservation challenge is the low-quality paper often used, which would yellow and degrade due to residual acid in the treated pulp from which the paper was made. In the worst case, old copies can crumble into small particles when handled. Mimeographed copies have moderate durability when acid-free paper is used. [18]
Litmus paper after being used. The main use of litmus is to test whether a solution is acidic or basic, as blue litmus paper turns red under acidic conditions, and red litmus paper turns blue under basic or alkaline conditions, with the color change occurring over the pH range 4.5–8.3 at 25 °C (77 °F). Neutral litmus paper is purple. [2]
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Japanese paper: Paper is dissimilar to parchment in both appearance and behavior, which can pose the future issue of storing an object with composite materials. Paper infills can be toned with watercolor or acrylic paints to better match the original parchment appearance. Acrylic-toned papers are treated with various adhesives such as B-72 ...