More extensive damage has been done to records by unfavorable atmospheric conditions than by any other single factor. This text discusses this premise in depth. Loss may be physical or chemical. Usual conditions for the storage of paper and parchment are as follows: RH should not be lower than 50% nor higher than 65%. The temperature should be not less than 15 degrees C (60 degrees F) and not higher than 18 degrees C (65 degrees F). Specifications for other factors are also given in this article.