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The NL operating concept

What should be deacidified?

The NL has set three priorities for the deacidification of its collections. First priority has the preventive treatment of the collections from between approximately 1930 and 1980 with good usability. The period before 1930 where usability is partly restricted, has second priority and collections after 1980, where mixed acid and alkali papers are present, have third priority.
The papersave swiss process is suitable for treating 90% of those documents from the general collection that require attention. Vellum-bound and certain leather-bound books are separated out. Slight changes are accepted in up to 5% of the treated documents. For the time being, serial publications are being treated. Corporate publications and most of the monographs in the general collection have already been completely treated and, for the time being, the newspaper collections are not being treated.

What is the procedure?

The NL workflow comprises data processing, preparation of the collection, packing, quality control, returning to the shelves and final data processing. In order to make use of synergies, there is close cooperation with other services and sectors, particularly with the stacks and logistics service, and alphabetic cataloguing. In the case of monographs-signatures for example, an inventory of the collections was linked to paper deacidification. During the deacidification process, the documents are unavailable to the general public for eight weeks.

How is it controlled?

The quality assurance concept is based on the quality standards in the revised version of 18 May 2004. This document is part of the outline agreement with Nitrochemie Wimmis AG, and regulates the procedure with regard to safety, infrastructure and logistics. Fifteen quality criteria that must be fulfilled by 95% of the documents are formulated. Control takes place on random samples of the original material both before and after treatment. In addition, in each batch, three standardized test books are also treated and analyzed.
Optical-tactile tests are carried out at the NL. For every test specimen, a condition report is made and, before and after treatment, the cover, paper and printing are controlled for depositions, colour changes, efficiency of the binding and odour. The physico-chemical part of quality testing is carried out in the Nitrochemie Wimmis laboratories. These laboratories are accredited according to SN/EN 45001 as a testing centre for paper.

How is it documented?

After deacidification, for every document treated, a deacidification remark, in MARC21 format, is created in field 583 of the bibliographical record in the NL library catalogue, Helveticat. The deacidification remark is visible to everyone and contains the item number, the treatment remark, the kind of treatment and the treatment batch. Five documents per batch, tested as random samples by NCW within the framework of quality control, are additionally given seven test values. It is thus guaranteed that the treatment is documented for future reference as well as for long-term observation. For collections that are not recorded at the item level in Helveticat, a packing list serves as proof of deacidification (example: corporate publications).

Further information

A detailed description of the workflows and quality control can be found at :
Back to overview Paper deacidification

Last updated on: 02.04.2012

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