Introduction

This document intends to define a permanent and durable paper that is most suitable for indefinite storage, e.g. in archives, libraries, and museums, and that will show no or only slight changes in optical and mechanical properties when stored and handled for a long period. Such papers can be used for books as well as for files, documents and other records that are to be stored and used permanently for legal, cultural policy or other reasons. For this purpose, this document provides a method for specifying paper, which, according to the present state of knowledge, has a high degree of permanence and durability.

As research indicates that the deterioration of paper is due to the presence of cellulose-degrading compounds in the paper furnish and materials incorporated in the paper during manufacture, papers eligible for permanent use are required to be free of any type of acid sizing or other acid-producing substances, and of oxidizable matter that causes undesirable discolouration, e.g. lignin or recycled material of uncertain composition.

To ensure durability over time, well-defined fibre sources are important. This document requires a specified fibre composition in order to ascertain a low degree of oxidizable or acid-producing substances and to ensure durable strength. In addition, strength is tested through both tearing resistance and folding endurance.

This document is based on a small number of quantitative tests for which limiting values have been specified. Paper classified in accordance with this document shall show measurement results within the specified limits for all prescribed tests.

There are two other International Standards, apart from this document, regarding different applications of paper:

— ISO 9706 , which describes permanent paper with the same permanence requirements as for this document but not including durability (ability to withstand the effects of wear and tear during use).
— ISO 20494 , which describes paper for general graphic applications, not intended for permanent storage, including newspapers, magazines, catalogues, books, office printouts and copies where changes in optical properties over time can be tolerated.

This document and ISO 9706 differ from ISO 20494; they are not comparable either in approach or in method. In ISO 20494, the decrease in mechanical-physical strength that a paper suffers when subjected to moist heat treatment for up to 12 days is the basis for defining service life.

Conversely, this document and ISO 9706 are based on the fact that acid-catalysed hydrolysis is the major cause of the degradation of cellulose, the substance that provides strength to paper, and that this acid hydrolysis is strongly inhibited if an alkaline buffer and no or little acid-forming substances are present in the paper. Furthermore, this document and ISO 9706 define a resistance to oxidation, which requires the paper to have a Kappa number of less than 5, corresponding to about 10 g of lignin per kg of paper. This document and ISO 9706 therefore specify a paper that is expected to remain substantially unchanged over time in long-term storage.

Both ISO 9706 and this document evaluate the permanence properties of the paper. For a document to be permanent, however, it must be noted that both a permanent paper substrate and a permanent recording method (i.e. writing, printing or copying) must be used in combination. Permanence and durability of recording materials are tested according to ISO 11798.

This document may be used as a stand-alone specification. It may also be incorporated as a component in other specifications used in trade or as national or international standards for more specific purposes.

BS ISO 11108:2025

Information and documentation. Archival paper. Requirements for permanence and durability

Current

Published:

31 May 2025