Acidic paper

[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.

The gradual and eventually complete deterioration of the paper as the cellulose chains disintegrate is known as "slow fire".

Paper acidification may be accelerated by environmental factors, especially nitrogen and sulfur oxides in polluted air.

[9] A large-scale de-acidification project was carried out in Poland, the Acidic Paper Multiannual Government Program[10] of 2000–2008.

[11] The American Bookkeeper technology was chosen, using a deacidifying agent of fine crystalline magnesium oxide suspended in an organic liquid perfluoroheptane, neutral to inks, paints and dyes.