When the situation affects more material than can be immediately dealt with, the recommended course of action for books and other paper materials is freezing (Waters, Principles). While freezing alone will neither kill most mould spores, nor aid in drying the collection, it will stabilize the material to prevent further damage and deterioration. This allows the librarians to assess the damaged collection in a thorough manner.
In addition to halting mould growth and increasing the likelihood of saving coated papers (which will be discussed below), freezing has other benefits for wet books. For example, freezing will also stabilize water-soluble inks and dyes, preventing further running and feathering (Waters, Principles). The way in which materials are frozen is also important. As Waters points out, "The size … of ice crystals is governed by the rate and temperature of freezing" (Waters, Cold Temperature). Larger crystals will force material to swell further. Therefore, if a rapid process such as blasting freezing is used, ice crystal size is kept to a minimum, and thus further damage will also be minimized.
Waters admits that restoration "can be a costly process" and suggests that "the high costs involved do not justify the salvage and restoration of books which are in print and can be replaced" (Waters). Diane B. Lunde concurs, and says that while this was not a viable option for their library, due to the nature of the damaged items, "Discarding a damaged collection is a realistic possibility that each library faced with a disaster should seriously consider" (6). She gives the example of a public library branch with a collection of current material. In such a situation, the cost of salvaging and restoring the collection might easily rise higher than the costs for replacement.
In addition, salvaged books rarely look as good as they did before the disaster, and they simply are not as nice to touch, look at, and use. This issue was of particular concern to Lunde and the rest of the staff at the Colorado State University (CSU) Libraries following their flood in 1997. She reports, "Normally we do not send a mold-stained volume back to the collection, but the disaster resulted in thousands of mold-stained books" (7). The staff wondered if patrons would be "leery about using mold-stained, wrinkled, misshapen books" (7). CSU Libraries did a small, quick study to investigate this issue and discovered that, for their patrons at least, appearance of the volume was the least important factor in determining if they would use a volume, while readability was the most crucial (7). In light of this, it is important to remember that for the patrons of a library, a wrinkled, stained book is more useful than no book at all.
Waters continues his discussion with a warning to readers that "decisions relating to these factors [what books to salvage and restore] are virtually impossible to make during a salvage operation" (Waters). The proof of his words is sadly born out in Martin's report of the decision made at the Corning Museum during the initial salvage operation "to abandon part of the periodical collection, believing that it could be replaced without too much difficulty. In time we would rue this decision, since many journals proved almost impossible to find" (235). This experience lends support to Waters' subsequent statement, "On the other hand it might be unwise not to attempt to salvage everything" (Waters). Given the relatively low costs of freezing, this is an option that should be given serious consideration if there is any doubt or question as to the ease and cost of replacement of damaged items.
Although there is no updated estimate in the revised version, in 1979 Waters reported that cold storage space would cost "about 50 cents per 100 pounds per month in 1974" (1979, 5). For the Corning Museum, freezing their periodicals to be evaluated when time permitted may have saved them a lot of effort and money at a later date when they were trying to reacquire the lost items. However, Martin reported that "By the time the last volumes were placed in boxes and on route to the freezers [5 days after the flood], colorful mold had begun to appear" (235). It is possible that those periodicals (or other materials) would have been lost to mould anyway, had they taken time to pack up the extra material.
As mentioned above, mould can begin to appear in as little as 48 hours. It is worth noting at this point that books immersed in water will not develop mould (Spawn, 244). In light of this, Waters states that cloth or paper bound printed books will not be further damaged by remaining submerged in clean, running water, and may be left that way for a period of up to two weeks (Waters, Cleaning). While this is not recommended as a general course of action, if the alternative is leaving the books in a warm, humid area, immersion is preferable.
Perhaps the category of books that causes the greatest problems for librarians in the event of water-damage is that of coated books. Coated pages look and feel nice, but when they get wet, the pages begin to stick to one another. If a book made of coated paper gets wet and then is allowed to dry normally, the pages will bind themselves together into a solid block and the book will be useless. Currently, the only way to save a book on coated paper once it gets wet is to prevent any drying from taking place before the book can be frozen. If the books cannot be frozen immediately, they must be kept wet (Waters, Coated Papers). One recommendation is to pack these books in boxes lined with garbage bags, and then seal the bags to keep the moisture inside ("Disaster Response").