Identification, Causes, Classification and Treatment of Foxing: A Literature Review

Abstract

The preservation of paper artifacts poses a serious problem for libraries, archives and museums worldwide. One of the main problems is FOXING. Although there have been extensive studies to determine what causes the brown marks “FOXING” since 1930s, its causes are not yet completely understood, there remains confusion and uncertainty as to what causes foxing, whether there is a single cause or multiple ones, and whether there is more than one type of foxing. There are currently three major explanations for foxing which have been proposed most often: a) fungal activity, b) metal-induced degradation, and c) multiple causes. Recently, a fourth explanation has been proposed which attempts to explain foxing stains within the context of general discoloration of paper caused by the interaction of moisture and cellulose. Unfortunately, most of the published research on foxing neglects to provide accurate and complete information concerning size, shape, depth (within the sheet), or fluorescence pattern (or absence thereof) when describing foxing. In the present work, we try to provide criteria for the differentiation of foxing problems from other stains in paper, to ascertain, to the extent possible, the cause(s) of a foxing stain in paper, to record established methods of identification used by both conservators and research scientists, to identify areas needing further research and to assemble treatments appropriate to various foxing stains.