Hello Everyone,

Changing acid-free housing materials "every several years" could mean as infrequently as 20-25 years, or more.  The rate at which these organic materials age and degrade depends upon the environment in which they are stored. If light levels, temperature and relative humidity are controlled, your acid-free housing materials will have a longer life span--as will your quilts.

There are a couple of Chlorophenol red pH indicator pens available on the market that can be used to check the pH of housing materials--NEVER use these pens on quilts or other historic artifacts.   University Products - www.universityproducts.com (Lineco's pH Testing Pen) and Gaylord - www.gaylord.com (Abbey pH Testing Pen) are both easy sources to order from.  

Kathleen
>>>>>>>>>>>>><<<<<<<<<<<<<<<<
Kathleen Kiefer
Associate Textile Conservator
Winterthur Museum, Garden & Library 

-----Original Message-----
From: Joan Kiplinger [mailto:[log in to unmask]] 
Sent: Thursday, July 03, 2003 10:27 AM
To: [log in to unmask]
Subject: acid-free materials


         Pros advise to change acid-free tissue and containers every several years or so for continued preservation of contents. This led me to wonder how do we know how fresh these items are when we purchase them?  What if they have been "hanging" around for a year or so before being sold?
       Does anyone know how vendors determine shelf-life of these archival supplies to ensure us full-life value?