3. Implications for library materials

Virtually all organic materials are susceptible to some species of mold and therefore to mold growth. The organic materials in library collections include, but are not limited to: cellulosic fiber; sizes and fillers of starch, casein and gelatine; natural adhesives, including starch paste made from vegetable matter and glues from animal skins; some synthetic adhesives; leather; and the gelatine on negatives and photographic prints. In addition, dust and dirt can provide additional nutrients required by the mold. All of these materials are hygroscopic, that is, they attract and hold moisture.

Despite this overall vulnerability, a variety of factors will affect the actual growth of mold within the library collection. Certain papers, leathers, bookcloths and adhesives are more susceptible to mold growth than others. In most cases the librarian has little control over the composition of the materials in the collection. However, a knowledge of the nature of those materials is necessary in order to make informed decisions as to why the infestation has occurred, ho,; to treat those items obviously affected, and whether it is likely that the problem will spread throughout the collection.

For example:

- The appearance of mold on only the leather bound books indicates that the active spores are specialized in their nutrient requirements. Since molds are selective, if no cloth covered or paperbound books in the immediate vicinity are involved, emergency treatment can be concentrated on the leather volumes.

- If the growth appears only around the head cap, or on the edges of the text next to the turn ins on the boards, it is likely that the nutrient source is the adhesive used in the binding.

- If only a few ranges or a few stack sections in the area are affected, the problem is most likely one of a microclimate. The affected items can be removed and efforts to modify the environment can be localized to that area.

Innumerable examples could be given, however the point is that a knowledge of the materials, an analysis of the nature of the problem, and an understanding of the interaction between the two can greatly reduce the potential damage.