Foxing
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Foxing is an age-related process of deterioration that causes spots and browning on paper documents such as books, postage stamps, old paper money and certificates, and on textiles such as clothing and artists' canvasses. The name may be a variant form of the English West country dialect term foust and Scots foze, to become moldy.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Alternatively, it may derive from the fox-like reddish-brown color of the stains.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Paper so affected is said to be "foxed".
Foxing is seldom found in incunabula, or books printed before 1501.<ref>Template:Cite journal</ref> Decrease in rag fibre quality may be a culprit; as demand for paper rose in later centuries, papermakers used less water and spent less time cleansing the rag fibres used to make paper.<ref>Template:Cite book</ref> An early work of art to have been affected by foxing is the Portrait of a Man in Red Chalk, a drawing on paper by Leonardo da Vinci.<ref>Template:Cite journal</ref>
Foxing also occurs in biological study skins or specimens, as an effect of chemical reactions or mold on melanin. Textiles, such as articles of clothing, so affected may also be said to be foxed.<ref>Template:Cite journal</ref>
Aside from foxing, other types of age-related paper deterioration include destruction of the lignin by sunlight and absorbed atmospheric pollution, typically causing the paper to become brown and crumble at the edges, and acid-related damage to cheap paper such as newsprint, which manufacturers make without neutralizing acidic contaminants.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
Causes of foxingEdit
The causes of foxing are not well understood. One conjecture is that foxing is caused by a fungal growth on the paper.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Another is that foxing is caused by the effect on certain papers of the oxidation of iron, copper, or other substances in the pulp or rag from which the paper was made.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> It is possible that multiple factors are involved. High humidity may contribute to foxing.
Repairing foxed documentsEdit
Foxed documents can be repaired, with greater or lesser success, using sodium borohydride,<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> proprietary bleaches, dilute hydrogen peroxide or lasers. Each method risks side effects or damage to the paper or ink.
Another method is to scan the image and process that image using a high-level image processing program. This can usually remove the effects of foxing while leaving text and images intact.
In biological specimensEdit
It is generally not advisable to repair study specimens, except perhaps for mechanical damage. Type specimens should – if at all possible – not be altered in any way. If foxing affects the study value of a specimen (e.g. in bird or mammal skins or in insects, where it may affect diagnostic coloration), this might rather be remarked on the specimen label. Color standardsTemplate:Sfn can provide a means of documenting coloration before or in the early stages of foxing.
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Related WorksEdit
- Smithe, Frank B (1974): Naturalists' Color Guide Supplement. American Museum of Natural History, NYC. Template:ISBN.
- Smithe, Frank B (1975-): Naturalist's Color Guide. American Museum of Natural History, NYC. Template:ISBN.
- Smithe, Frank B (1981): Naturalist's Color Guide Part III. American Museum of Natural History, NYC. Template:ISBN.
- Template:Cite book