Posted: 2015-01-01 15:44
Every booklover mutters unhappily over the reddish-brown spots which appear unheralded in his favourite volume, or spoil the one he is minded to buy, perhaps, unconsciously triggering a synaptic flash of the liver-spots he/she will show in later life. In the 150 years since this staining problem was named in print, countless attempts have been made to define its cause.
Received wisdom blames metal deposits in the paper furnish, the less coy experts specifying ferrous/ferric compounds. Other regular suspects include the percentage of wood pulp, or fungal or mould infection, or damp causing chemical reaction in the acid pH of some papers, the favoured culprit depending on the expert asked.
Yet every single given reason can be shown to fail to explain all instances of brownish stain encountered: it seems there are many kinds of foxing. Despite this evidence some research papers exhibit rather incautious certainty over their deduced cause for the annoying spots. One study declared that,' foxing never or hardly ever occurs in paper made with a high percentage of mechanical wood pulp '.
Mechanical pulp is made by mechanically grinding down complete logs into fibre, as opposed to cooking chipped wood in caustic soda solution to remove the lignin binder from the cellulose fibres (Chemical Pulp). Yet the same study declares that iron causes foxing from ferrous compounds in the earth taken up by the tree through its roots, and presumably still present after mechanical conversion into pulp? One American commentator notes the introduction of iron machinery and rag-based furnish coincides with the onset of foxing, yet elsewhere the replacement of rag by by wood-pulp is blamed.
A European study in 2002 by a group of ten scientists attacked the elusive problem-cause with infrared spectroscopy, micro-X-ray fluorescence spectrometry and laser induced break-down spectroscopy and found:' the foxing phenomenon is related to a strong oxidation of the cellulose chain...concerning colour, no great differences between ferrous and ferric contaminants was found '.
That group failed to improve on the book/manuscript conversion based study made in 1989, originally in German/Dutch journals. This admitted that while necessary elements and conditions for foxing could be cited, no complete explanation for the whole range of spotty discolouration in books had been derived, and so, ' the term foxing is not yet unambiguously defined '.
' The Paper Conservator ' the Institute of Paper Conservation's annual journal regularly carries articles on foxing, including some seminal studies. Most admit their results while proven for a particular sample do not constitute a General Theory, so if you want to become famous, you know what to do.
(The above article was anonymous and appeared in, ' The Society of Bookbinders Newsletter '. (August 2005).