ABSTRACT
The art of preserving is as old as human civilization itself. The multitude of preservation research activities, carried out worldwide, indicates an international awareness of the need for scientific tools to tackle the problem of degradation of the world's cultural heritage. A more critical, hands-off approach evolved, based on a better understanding of conservation problems and of decay mechanisms of objects, as well as on the acknowledgement of the failure of some modern materials that had previously been introduced into the field. Researchers from the nineteenth century already wondered why certain papers degraded more than others. Artificial or accelerated ageing tests are used to determine the permanence of paper and to predict the long-term effects of a particular conservation treatment. The natural ageing process of paper is speeded up by subjecting it to extreme conditions in a climate chamber. A complicating factor is the way in which the paper is exposed to the ageing conditions.
