| Prevention and treatment of mold in library collections with an emphasis on tropical climates: A RAMP study |
|3. Implications for library materials|
|3.1 Vulnerability of materials|
In 1940, Beckwith and his co-workers isolated 55 different mold cultures from old book papers, including eleven genera, of which Penicillium and Aspergillus were the most commonly found.1 In the study, spores were removed from the papers, transfered to a culture medium and grown under laboratory conditions. This is not to say that all of them would have been able to use the paper as a medium for growth, but certainly some of the strains of Aspergillus and Penicillium would be likely to attack cellulose or one of the numerous paper additives, sizes, fillers or coatings. At least 180 genera or species of mold are known cellulose destroyers, i.e., they use the cellulose fiber as a nutrient.2
Other molds that do not actually consume cellulose may damage paper by weakening the fiber bonding as they feed on other materials in the paper. The fillers, sizes and coatings added to the paper during manufacture to improve printability, texture, color or brightness are a potential source of nutrients, and may include starch, gelatine and casein. Rosin size was found by Beckwith to inhibit fungal growth;3 however, rosin is acidic and has been found to accelerate the chemical deterioration of paper and its presence is not cause for rejoicing. Very little is know about the various synthetic sizes, as much of the research in this area took place before they were in common use.
Paper in bound volumes is less vulnerable to high ambient relative humidity than unbound paper. Cryptogamic fungi seldom occur in closed volumes under such conditions, but rather on the bindings and on unbound sheets of paper exposed during prolonged periods of dampness. Foxing, on the other hand is commonly found in text blocks.
In cases of flood or other severe wetting, book paper may be considered to be more vulnerable, since the bulk of the volume and the compression of the paper at the spine slow the drying process considerably.