Defining deterioration state of objects

What is the acceptable baseline change of objects?

Understanding the deterioration of certain materials is critical to providing effective stewardship. We are supporting the development of predictive tools and models to determine the deterioration state of archival records.

Projects

Heat-set tissues: a retrospective analysis at The National Archives 1960-1990 (2006-2008)

The lamination of documents found wide application in libraries and archives in Europe and North American from the 1960s, and continues to be used in some collections today. Unfortunately, in some cases this technique has proved deleterious to the documents, both chemically and mechanically. The objective of this project is to deliver a retrospective analysis of laminating techniques used at The National Archives between 1960 and 1990, in order to establish the long-term stability of the materials used and to assess the effects of their use on original materials. In particular we have considered the long-term bond strength to certain substrates, flexibility and the presence of residual adhesive in the paper after removal of the tissue. Analysis thus far has confirmed the use of four broad categories of materials: paper tissue, nylon (area bonded fibre) tissue, acrylic and polyvinyl acetate adhesives. None of the combinations of carrier tissue and adhesive is showing threatening degradation signs, either visually or at molecular level, to the documents. We intend to further our investigation into the life expectancy of these materials and continue to monitor their long-term stability.