The chemical and physical stability of these materials depends on the quality and processing of the products used in their manufacture, together with the design and construction of the final artefact. Over the centuries, the pressures of mass production have greatly reduced the quality of what is received in libraries today. Binding techniques have been abbreviated to such an extent that many books are now held together solely by adhesive. These bindings have to be handled and supported with great care. Much of the paper stock manufactured after 1850 is highly acidic , and is self-destructing.
Acidity can cause paper, cloth, and leather to become brittle and discolour.
It may be introduced during the manufacturing process, or may be present in the raw material, and in inks or pigments. Photographs, microfilm, optical, magnetic and audio-visual media, also have inherent preservation problems and are very easily damaged. Like all library material, they degrade continually and therefore need to be stored and used carefully if they are not to perish prematurely. The Department's approach therefore has to be tailored accordingly.