Adhesives

Materials: Part 1

Most historical books will use some kind of glue somewhere in the binding to hold it all together, whether that is to adhere the covering materials down or attach the supports to the boards. Often books will break because the adhesive has failed – becoming brittle, cracking, or losing tack. Other times it is the binding materials that deteriorate, and removing them intact requires removing the old adhesive.

Traditionally, animal glue is the most common adhesive used in bookbinding. This is usually derived from the skin of animals, such as rabbits. It turns liquid upon heating, and makes a strong, flexible glue. Over time this adhesive can deteriorate: exposed to heat and fluctuating environmental conditions the molecules can crosslink and turn the glue hard and brittle.

2. Cooking wheat starch paste (Photo: Nikki Tomkins)
2. Cooking wheat starch paste (Photo: Nikki Tomkins)

When new material is used to help reattach the boards during conservation, that too needs to be adhered into place. Introducing new adhesive into a binding is a considered choice: it’s important to choose a substance that is in keeping historically, can be removed if needed, and suits the materials present both old and new. Japanese Jin-Shofu Wheat Starch Paste is used almost exclusively in the conservation of Crouch’s collection. This is a refined version of flour paste, where the starch is separated from the rest of the wheat. Here in the studio, it is made to a 25% w/v in deionized water concentration, and cooked for 40 minutes until sufficiently tacky.  For binding conservation, the paste is kept dry and viscous. This makes it stronger and reduces the risk of introducing too much moisture into old materials. Moisture can darken old deteriorated leather, or weaken parts of the structure.

In the case of the Crouch volumes, this adhesive has been used liberally on the spine and boards to adhere the covering leather. When the board attachment breaks down, it is necessary to separate the original leather from the spine or the boards. This can usually be done mechanically: using a sharp blade or very thin spatula. Sometimes the spine will need to be cleaned of old glue before applying new linings. Animal glue will soften with moisture, and so a poultice is applied that gradually works on the glue without making the paper spine folds underneath too wet. The glue can then be carefully scraped away.

Sometimes flour pastes are also used in traditional bookbinding. This is derived from wheat flour, where heating the flour in water causes the grains to swell and secrete proteins that create the tackiness. You might find it used to adhere a pastedown, or a tipped in paper page. It is generally less thick and strong as animal glue, and can be more useful for the more fragile paper components in a binding – however, both can be found interchangeably on historic bindings.

When new material is used to help reattach the boards during conservation, that too needs to be adhered into place. Introducing new adhesive into a binding is a considered choice: it’s important to choose a substance that is in keeping historically, can be removed if needed, and suits the materials present both old and new. Japanese Jin-Shofu Wheat Starch Paste is used almost exclusively in the conservation of Crouch’s collection. This is a refined version of flour paste, where the starch is separated from the rest of the wheat. Here in the studio, it is made to a 25% w/v in deionized water concentration, and cooked for 40 minutes until sufficiently tacky.  For binding conservation, the paste is kept dry and viscous. This makes it stronger and reduces the risk of introducing too much moisture into old materials. Moisture can darken old deteriorated leather, or weaken parts of the structure.

3. Wheat starch paste, sieved and ready for application (Photo: Nikki Tomkins)
3. Wheat starch paste, sieved and ready for application (Photo: Nikki Tomkins)

By Nikki Tomkins
Project Conservator

Cataloguing Crouch: detective work

Much of Nicholas Crouch’s library exists as bound volumes which include between two and fifty distinct bibliographic works. These Sammelbände have been kept together in Balliol College Library since at least 1799, shelved among other tract volumes with varied provenance. Within this collection, Crouch’s books are frequently easy to identify due to his meticulous hand-written contents lists; other typical stylistic features of a Crouch binding are described here.

Many of Crouch’s donations to the college were recorded in the Library Benefactions Book, which provides a list of 319 volumes acquired by the library upon Crouch’s death in 1690. However, we know from comparing the records in the Benefactions Book to the items catalogued so far that not all of Crouch’s books were bequeathed at this time. In particular, many of the Crouch volumes composed of 16th century texts are not listed in the Benefactions Book.

Crouch’s name and bequest are recorded in elaborate calligraphy (Balliol College Library Benefactions Book, page 194)
Crouch’s name and bequest are recorded in elaborate calligraphy (Balliol College Library Benefactions Book, page 194)

At present we don’t know precisely when these unlisted items arrived in the library. A small gift of two volumes is recorded in 1656 as ‘P. Fronseca Metaphysica’, but other than this we haven’t found evidence of additional donations from Crouch. One possibility is that Crouch was also purchasing texts for the college library, and that certain volumes were chosen by him but not intended for his personal collection.

From the descriptions, around half of the Crouch items listed in the Benefactions Book appear to be Sammelbände. These volumes are frequently listed as ‘A Collect. of Tracts’, followed by a description of the first (or ‘ye 1st’) item in the volume.

Many items in the Crouch bequest are listed as ‘A Collect. of Tracts’; others are entered under author and title (Balliol College Library Benefactions Book, page 195)
Many items in the Crouch bequest are listed as ‘A Collect. of Tracts’; others are entered under author and title (Balliol College Library Benefactions Book, page 195)

The remainder of the Crouch books are listed under author and title. These works are scattered throughout Balliol’s collections, frequently uncatalogued. Because they contain only a single bibliographical item, they lack Crouch’s distinctive contents lists and are often more difficult to definitively identify.

One characteristic of many of the Crouch volumes catalogued so far is an early shelfmark in the style:

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These shelfmarks appear to be inscribed in Crouch’s distinctive hand:

Shelfmarks side by side with Crouch MS
(Balliol College Library shelfmarks 910 b 8, 300 i 9, 905 c 1, 915 c 7)

Seeking out these shelfmarks will allow us to confirm the Crouch donations recorded in the Benefactions Book, and to identify volumes not listed there. The shelfmarks may also give us clues as to how Crouch arranged his personal library. It’s estimated that there are between 100-200 Crouch books to be located in this way. These volumes will be gathered together and catalogued as part of the current project, and kept with the Sammelbände. In this way, the majority of Crouch’s library will be reunited for the first time in 300 years.

By Lucy Kelsall
Project Cataloguer

Split spines and broken joints

Conservation is continually informed by principles of minimal intervention in considering a treatment’s approach: finding solutions to problems that avoid loss of material and preserve as much of the original structure as possible. In the case of Crouch’s collection, many of the volumes have splits in the spine and detached boards.

The conventional solution would be to reback the volume: removing the original spine, and providing new linings and leather over the spine and onto the boards. This forms part of the board attachment and allows access to reinforce the sewing. Often the original spine is then re-adhered, however this is not always possible when the leather is in a very degraded condition.  Additionally, the introduction of layers of new material on the spine can affect the opening characteristics of small, narrow volumes. Loss of the original spine and the impact on the opening structure are strong arguments for finding an alternative solution.

Example of a detached left board, and split in the spine (Photograph by Nikki Tomkins)
Example of a detached left board, and split in the spine

It is often easier to lift just the label when the spine covering leather is highly deteriorated. This allows access to the spine where linings of Japanese paper and linen are applied. This not only consolidates weaknesses and break points in the spine, but also forms part of the board attachment.

Replacing the label (Photograph by Nikki Tomkins)
Replacing the label

Once the label is replaced, the treatment is less visually obtrusive than a reback. Textile and Japanese paper is also used at head and tail of the spine, where the leather is easier to lift. This technique is not as strong for the textblock as rebacking, but it does preserve most of the spine while still imparting considerably more structural strength. The final object is still fragile and should be handled with care, but the boards are reattached and the breaks in the spine are held together.

  1. Removal of the label in one piece, exposing the leather below
  2. Using a poultice of wheat starch paste, the leather and animal glue are scraped away exposing the backs of the sections.
  3. A first layer of Japanese paper is applied using wheat starch paste. This provides a protective barrier between the textblock and subsequent layers, and a primary layer to hold together the sections.
  4. Layer of textile adhered to bridge splits and consolidate the textblock, with extensions either side for the board attachment.
  5. Toned paper adhered, providing an extra layer while also matching the repair to the original covering leather. Textile and toned paper are also inserted at the head and tail of the spine to support the board attachment.
  6. The original label is adhered back in place, and the lining extensions adhered underneath the covering leather on the boards.


By Nikki Tomkins
Project Conservator

Anatomy of a binding

Each aspect of a book’s binding holds information about its history:  from the materials used, to the mechanical structure. A key part of this project is documenting specific aspects of Crouch’s bindings, both to understand their damage and to trace the history of the collection.

The following diagram illustrates some of the key components of a binding:

Key components of a binding (Sketch and photograph by Nikki Tomkins)

Book bindings can vary hugely, and often certain styles and techniques will be specific to one bindery. Crouch’s collection was probably commissioned by Crouch himself, from an Oxford binder. There are clear stylistic similarities throughout the collection. The following diagrams illustrate some of the typical features of a Crouch binding:

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However, among these common stylistic features there is still a great deal of variation: from the tool of the corner fleuron used, to the material of the sewing support and the colours of the endbands.

Examples of different tools used (Sketch and photograph by Nikki Tomkins)
Examples of different tools used
A selection of Crouch bindings displayed fore edge out, as they were probably intended to be (Photograph by Nikki Tomkins)
A selection of Crouch bindings displayed fore edge out, as they were probably intended to be

Each of these details are documented when an item comes into the studio in order to build up a body of data on the bindings and begin to trace a timeline of when, where and how they were bound together. It will teach us a little more about the mind of Nicholas Crouch, a man who evidently took pride in the organisation of his collection.

By Nikki Tomkins
Project Conservator

A very hard frost and exceeding cold weather

Why not take a leaf out of Nicholas Crouch’s diary this festive season?

December 1669: according to Crouch, the only noteworthy occurrence of the month was a hard frost on Christmas morning.

However, in keeping with Crouch’s meticulous nature, the lines have been ruled precisely and the astrological symbols drawn with care. Sundays and “Xtmas Day” have even been picked out in red ink.

We hope that your celebrations are likewise accurate, annotated, merry and bright.

"Xtmas Day: a very hard frost and exceeding cold weather to the end of this month." (Balliol College Archives shelfmark MS 355)
“Xtmas Day: a very hard frost and exceeding cold weather to the end of this month.” (Balliol College Archives MS 355)

Broken bindings: a closer look at conservation (part II)

This is part II of a two-part series on the challenges of conserving Nicholas Crouch’s library. Part I may be viewed here.

Most of the treatments will use a combination of Aerocotton, sewing threads and Japanese papers. These materials are chosen for their strength, quality, and flexibility; are toned using acrylic dyes with a good light fastness, and adhered in place using a 25% wheat starch paste. The size of the book, scale of the problem and condition of the leather are all important factors to weigh up when choosing a suitable treatment. Where the outer leather is beginning to split at the head and tail, often it is enough to lift the leather and insert bridges of toned material between the spine and the board. This pulls the boards back into place, and gives support to the unbroken board attachment.

Before (left) and after (right) treatment, showing how toned Japanese paper can be used to bridge splitting joints

Where the board is completely detached, more is required to make sure that the repair is durable. Given the condition of the leather, it is better to find solutions that interfere as little as possible with the original leather. If possible, sewing threads can be an excellent mechanical board attachment. Inserted into the middle of a section close to the joint, the sewing threads are twisted round the support, frayed out and adhered to the upper edge of the board. Toning in situ or covering with toned paper can further disguise the treatment, and consolidate the attachment.

The principal aim of conserving the collection is to make the objects accessible to readers  while preserving their original materials and structure, key components of Crouch’s collection. After treatment the books will still be fragile and should be handled with care: aspects such as restricted opening and degraded leather are inherent to the object. However, boards will be reattached and torn pages repaired making the objects far more accessible to researchers of both the content and the bindings.

By Nikki Tomkins
Project Conservator

Broken bindings: a closer look at conservation (part I)

This is part I of a two-part series on the challenges of conserving Nicholas Crouch’s library. Part II may be viewed here.

Binding together ephemeral material of divergent paper types, ages, and conditions, will cause a number of structural problems. The books in Crouch’s collection have typically wide spines for their small size, mainly because of the quantity of items that were included in the volumes. Animal glue was applied liberally to the tightback spines, which heavily resist opening. Given the stiffness of the volumes in a working collection, it is less of a surprise that so many show heavy creases and splits in the spine – probably indicative of a reader repeatedly forcing the book open at a particular point.

The restricted opening and small size of the volume mean that they are prone to breaking along the spine. Detached boards are also common where the leather and the supports break at the joint. (Photograph by Nikki Tomkins)
The restricted opening and small size of the volume mean that they are prone to breaking along the spine. Detached boards are also common where the leather and the supports break at the joint

Most of the items in Crouch’s collection have been covered with thinly pared tanned sheepskin. This is notorious for easily lifting and breaking down over time. There’s evidence of further damage to the surface of the leather: possibly from decades of being stored in rooms heated with open fires, and being exposed to smoke and fluctuating humidity. Many of the items have signs of a surface treatment to the leather, which has darkened in places and seems to have exacerbated the flaking, delaminating surface.

Detail of a leather surface showing the crazed and flaking condition (Photograph by Nikki Tomkins)
Detail of a leather surface showing the crazed and flaking condition

Most of the volumes in this collection use laced in sewing supports and the covering leather as the principle forms of board attachment. Degraded leather can start to split along the joint of a book, where it is constantly being flexed as the book is opened. Usually this will happen first on the left joint, as the beginning of the volume is opened more often than the end. This puts more stress on the supports which may also subsequently break leaving a detached board that no longer protects the textblock and is susceptible to loss. The majority of my work in the studio is finding ways to rebuild the book’s board attachment while preserving the fragile original leather as much as possible. There is always a balance that has to be made between the structural integrity of your repair, and the impact on the materials.

Other typical problems encountered in the collection are found in the textblock. Many of the pamphlets and tracts have had previous lives before being bound together, and this is evident from their variable conditions within the same binding. In a few examples the textblock edges have not been trimmed and are very fragile, still bearing signs of heavy wear and tear. This makes it difficult to handle without causing further damage.

Example of abraded page edges with numerous tears (Photograph by Nikki Tomkins)
Example of abraded page edges with numerous tears

By Nikki Tomkins
Project Conservator