In 1979 the Central Research Laboratory for Objects of Art & Science and the KB set up the working group Book Restoration. Over the years this working group has discussed many problems connected with the conservation and restoration of both 'old' books and 'modern' paper.
The Central Laboratory attached so much value to consultation and collaboration with people in the field that some time later a second working group Archive Restoration was founded to deal with problems specific to archives. In 1991, practical considerations led to the two working groups being merged to form the working group Archive and Book Conservation.
Conservation of bookbindings was one of the first concerns of the working group book restoration. The treatment of the cover material of the bookbindings is a logical first step in the whole process of conservation. It is also an operation which can be seen as 'mass treatment'.
The members of the working group had grave doubts about the effectiveness of the various products available, especially those intended for leather conservation. A number of existing leather conservation products were therefore tested on different kinds of leather. Research showed that the fats in pastes remain on the surface so that they have no useful effect on the underlying fibres at all: the effect of such pastes is cosmetic rather than remedial. Research also showed that the dressings contained far too many fats. Most of these fats, owing to the rapid evaporation of the added solvents, rise to the surface of the leather again, a process that is generally visible as a dark discoloration of the leather.
Nevertheless, a number of ingredients in the existing dressings, such as neatsfoot oil and wool fat (lanolin), are very useful for conserving leather. The problem was to find a good solvent: a solvent that would not evaporate too quickly (the fat needs time to adhere to the fibres) or leave behind any harmful by-products. In addition, a suitable method for neutralising the surplus acids had to be found.
In the early 1980s both institutions published guidelines for the treatment of bookbinding leather and parchment. (Voorlopige richtlijnen voor het conserveren van leer en perkament van boekbanden. Amsterdam/Den Haag 1982.) These were of a provisional nature because their compilers realised that further research into the effects of leather cleaning and conservation products was necessary. A more definitive version of the guidelines was eventually published in Dutch in 1987 (Goddijn, 1987).
The recommended treatments were primarily intended for the conservation of the majority of leather bookbindings. As yet no effective treatment had been found for alum-tawed and parchment bindings.
The aim of the guidelines was to provide an instrument for both the restoration studio and the individual book owner. But in the course of a few years it became increasingly clear that this intention did not work. There was a need for a more differentiated approach to bookbinding conservation and (hence) for a more conservator-oriented approach. Moreover, the standard procedure of adding a buffer to the dressing was now being questioned, partly because of critical remarks made during discussions at the congress of the working group Leathercraft Related Objects of the ICOM Committee for Conservation, at Offenbach in 1989. Encouraged by signals from conservators, the KB and the Central Laboratory decided to produce a new version of the Richtlijnen voor het conserveren van leer en perkament van boekbanden, aimed specifically at the book conservator.
The new guidelines aimed to:

  • devise a selection method for targeted treatment of each individual binding based on its specific damage, on the assumption that not every book needs treatment, let alone radical treatment.
  • introduce differentiation in the methods of treatment and the products used, based on the present 'standard' dressing.
  • develop methods and processes for the conservation of alum-tawed and parchment bindings.

In preparation for the new guidelines, an inventory was drawn up of practical problems affecting the conservation of bookbinding leather and parchment. This involved, among other things, conducting an inquiry among book and paper conservators.
Although these new guidelines, as noted above, are intended primarily for the (experienced) conservator, the possibility of wider public interest has not been overlooked. In addition to the actual guidelines for classifying by type of damage, procedural descriptions, and formula preparations, some chapters have also been devoted to related subjects, thus providing a more general idea of the problems involved in bookbinding conservation. It should be emphasised that it is impossible to cover every detail of a subject in a single chapter; the material is often too complex or too comprehensive. Readers are consequently advised to consult the specialist libraries of both institutions for supplementary information. To help the reader, a concise bibliography has been added at the end of these guidelines.
Although we have tried to be as comprehensive as possible, some aspects of bookbinding conservation have not been discussed. But the publication of these guidelines does not signal the end of research into methods and materials: the report should be seen as reflecting the current state of knowledge and experience in this field.
A brief summary of the chapter contents is given below.

1. Overview of leather and parchment manufacture
Although a conservator may in principle be expected to know the basics of leather and parchment manufacture, the editorial board thought it useful, especially for the (as yet) inexperienced conservator, to pay some attention to this. Aspects like bating, tanning and finishing greatly affect the durability and permanence of leather. The useful life of parchment, for instance, is closely related to the method of unhairing. In the manufacture of 'modern' parchment in particular there is a tendency to resort to harmful chemicals for this process.

2. Concise survey of conservation treatments
From time immemorial man has felt the need to 'rub something' into bookbindings, often in order to enhance their appearance, for example, to make them gloss. On the other hand bindings were, of course, also treated in order to preserve the leather. The diversity of means used for this purpose is amazing. This chapter provides a brief summary based on the literature.

3. Causes and phenomena of leather and parchment decay
This chapter discusses the major causes of decline in the quality of leather and parchment. Chemical damage can result from the use of certain chemicals in the manufacture of leather and parchment. In addition, air polluting substances also play a major role in this kind of damage. Physico-mechanical damage can be caused by incorrect and/or fluctuating temperatures and humidity, but also by too much or too little fat or moisture. Biological damage in the form of fungi may occur, especially in parchment. Finally, physical damage is a form of damage caused, for instance, by thoughtless handling and/or improper storage. The forms of damage discussed are illustrated with a few representative examples.

4. Damage categories and treatment
Visual assessment of the binding is basic to damage classification. It should be possible to decide on the basis of an external examination whether a book is suffering a specific kind of damage requiring treatment or simply needs to have an accumulation of dust and dirt removed.
If a particular type of damage, either chemical or physico-mechanical is observed, the pH value of the leather or parchment is determined. Partly on the basis of this pH value, the book is then assigned to a damage category and an appropriate treatment procedure. Leather and parchment bookbindings are dealt with separately here because the damage classification and treatment for leather and parchment are not identical.

5. Procedures and formulas for the conservation of leaather bookbindings and the treatment of specific kinds of damage
This chapter describes the various stages of the actual conservation treatment: cleaning, deacidification, buffering, conditioning, treating with emulsions or dressings, and impregnating. The conservation of several specific leathers, such as alum-tawed leather and leather with pigmented finishes, not covered in chapter 4, are discussed here. Also dealt with in this chapter are a recommended treatment for leather and parchment bindings overtreated with fat and ways of dealing with biological damage.

6. Procedures and formulas for the conservation of parchment bookbindings
In the past, reports dealing with the conservation of bookbindings usually neglected parchment (or, in some cases, unfortunately treated it as if it were identical with leather). Research into the proper treatment of parchment bookbindings was still in its early stages so no treatment for parchment was recommended, and rightly so. Besides, for a long time there was a commonly held fallacy that parchment needed no conservation because its inbuilt buffer of calcium carbonate (chalk) would protect it from pollution. But parchment can indeed be affected by pollution as well as by chemicals added during manufacturing or by dust and dirt in the environment. The various stages of parchment conservation are discussed; whenever these are the same as for the treatment of leather readers are referred to the chapter on leather conservation.

7. Analytical tests
By means of special pH indicator paper a reliable measure of acidity can be obtained. This is important in assigning the binding to a damage category and in determining the treatment procedure. Also important for an accurate insight into the 'background' of damage to leather and parchment are the ammonium and sulphate levels. These can be determined by the book conservator, although a correct interpretation of the results of this analysis will often require consultation with an expert in this field.

8. Documentation
In principle every treatment of a history artefact should be documented. It has become more or less standard procedure in institutions to draw up a report of both the restoration process and the conservation method applied to the binding. Later on supplementary information, such as a new buffer treatment, can be added to the report.

9. Storage and handling
Sound material care plays a primary role in preventing damage to books and their covering materials and is therefore an important part of conservation. The term material care refers not only to the way books are stored - lying or standing, in steel or wooden cases, in boxes or not - but also to the control of ambient conditions. This chapter looks at some important aspects, such as handling books, bookcases, storage materials, shelf-marks, climate control, lighting and exhibiting.

10. List of formulas
This chapter contains all the formulas referred to in these guidelines.

11. Concise bibliography
The bibliography provides a compilation of the references and other sources as indicated at the end of the chapters. This is supplemented by a number of other relevant publications which provide an opportunity for going into the subject more deeply.