Bookbinding and the Conservation of Books
A Dictionary of Descriptive Terminology

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dry-salting

A method of preserving hides and skins for storage and/or transportation before tanning, so as to prevent PUTREFACTIVE DAMAGE , by curing them in a very strong solution of brine—i.e., about 30 pounds of salt for every 10 gallons of cold water, followed by drying, or by WET-SALTING , followed by drying. In both methods, the hides are subject to a thorough and uniform salt penetration and are then hung up to dry. Dry-salting substantially reduces the weight of the hides and therefore the cost of transportation that is incurred in wet-salting; it also reduces or eliminates many of the dangers involved in simple DRYING (1) . Large numbers of hides, however, require great quantities of salt. In dry-salting, care must be taken that: 1) drying is carried out gradually and evenly; otherwise the hides may become too hot and partially gelatinize, which not only prevents drying of the inner layer and causes the hides to become hard and brittle, but also results in the gelatinized parts leaving holes when the stock is later returned to its normal wet condition; and 2) when the hides are to be tanned, they must be soaked in water until they have taken up as much water as they had before curing; dry-salted hides require more time and more careful soaking than does wet-salted stock.

Sodium chloride (NaCl) is the most commonly used salt for this process, but a salt "earth" known as KHARI, is actually to be preferred because it contains about 60% sodium sulfate (Na 2 SO 4 ), 20% magnesium sulfate (Mg SO 4 ) and 5% sodium chloride, and is less hygroscopic than common salt. It is more suitable for the hot, humid areas during the rainy seasons, from which most dry-salted hides are prepared. (248 , 291 , 363 )




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