Foxing on Paper: Analytical and Microbiological Evaluation

Abstract

Paper is a multi-component material and because of its complex and varied nature, research fndings can be difcult [1]. Old paper frequently develops spots which constitute a condition commonly known as foxing. Foxing on paper has been actively researched since the 1930s by conservation scientists and conservators to elucidate its causes and to establish protocols for detection, prevention and treatment [2]. The term is applied to stains of reddish-brown, brown, or yellowish color, generally of small dimensions, with sharp or irregular edges found in paper [2, 3]. Some foxing is due to fungal activity and other related forms of spotting are probably of chemical origin, both resulting in a physical degradation of paper. It is then difcult to state whether biological attack causes this degradation or whether it simply occurs on the substract of an already degraded paper, since sometimes biological attack is the only factor observed, while in others metal- induced degradation is present and interaction between both factors can also be found [4]. In order to defne the adequate conservation status and develop targeted restoration procedures for paper documents, it is crucial to understand the origin of foxing stains on paper.