Council on Library and Information Resources

Username (email)

Password

Isoperms--Note 1

Commission on Preservation and Access


Isoperms
Notes


[1] We should recognize that Equation 2 applies to papers in equilibrium with their environment. Individual closed books and tightly packed manuscript boxes are slow to respond to environmental % RH changes. Though their outside edges may equilibrate in minutes or hours, it often requires months for the moisture content in the center of a book to reach its equilibrium value for a specific % RH. For convenience we shall assume equilibrium with atmospheric conditions for both temperature (a very good approximation) and relative humidity (good only over relatively long time intervals).


Return to CLIR Home Page >>