All posts by Greg Sheaf

The Final Chapter: The Book of Dimma’s New Binding

As was detailed in the previous blog we carefully planned in advance the rebinding of MS 59 once the extensive additional repairs to the brittle and damaged vellum of the backfolds had been carried out. The opportunity was taken to photograph the backfolds prior to sewing as valuable clues to previous bindings visible at this stage would be again hidden once the manuscript was resewn and bound.

Fig. 1 The outside of bifolia from quire 4.
Fig. 1 The outside of bifolia from quire 4.

The traditional sewing frame was set up with the new linen cords attached and tensioned. The cords were fabricated by cabling unbleached linen thread to the required thickness. The sewing commenced with the new front vellum flyleaf followed by each of the six quires of the text block and finally the new back flyleaf. The linen thread was passed into the centre fold of each quire and out and around each of the double linen cord sewing supports. At the changeover point it passed into the next quire and the process was repeated travelling in the opposite direction. The sewing needle was modified by bending the shaft to allow an easier transition between the cords.

Fig. 2 Sewing MS 59 employing techniques practiced for centuries.

Once the manuscript was sewn it was removed from the frame and endbands were sewn at the head and tail with the same cabled linen cord as the endband. The endband thread was passed through a vellum ‘slotted spine’ which protects the backfolds of the quires and gives some resistance to the opening characteristics of the manuscript.

The next stage was the attachment of the new cushioned ‘blue jean’ binding boards. Channels were cut into their inner surface and the sewing supports and endband cores were laced on to give a very robust mechanical attachment between the text block and binding boards. Like the sewing, this work also emulates methods employed in early medieval book making.

Fig. 3 Sewing cords laced into channels cut in the board.
Fig. 3 Sewing cords laced into channels cut in the board.

The white alum tawed leather was prepared with the minimum of paring using the full thickness of the skin where possible. Starch paste was applied over the surface of the leather apart from the spine. The manuscript was covered, stretching the leather over the boards and turning in over the edges. The binding was then allowed to settle and dry under light weight. In order to attach the covering leather to the spine of the manuscript; a secondary endband combined with a primary stitch through the cover was sewn at the head and tail using two coloured threads.

Fig. 4 The new binding in alum tawed calfskin.
Fig. 4 The new binding in alum tawed calfskin.

In addition, a chemise made from linen, similar in form to the modern dust jacket, was sewn up and this will help keep the cover clean. A dropback box designed to apply slight pressure to the closed binding will keep the manuscript in optimum condition.

The finished structure opens with ease and with minimum strain on the thousand year-old vellum folia and the pigments and ink applied to their surface. The information recorded during the disbinding phase will help us better understand how this small ‘pocket gospel’ might have looked when it was first produced in central Ireland in the eighth century. The current binding will hopefully protect the precious contents into the next millennium.

John Gillis

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Rebinding Dimma

As discussed in a previous post, the decision was taken to remove the modern Roger Powell binding from the Book of Dimma, in order to accommodate digital imaging without undue stress to the brittle vellum and to carry out essential additional repairs to damaged backfolds of several bifolia.

Repairs to the calfskin vellum were successfully executed by bridging splits and areas of loss in the folds using a collagen based material called cecum, the source of which is a pouch connected to the large intestine of mammals. Once processed and degreased this membrane makes an excellent strong and flexible support to the areas of damage without adding bulk. The cecum is profiled to the correct shape and adhered with 11% isinglass, a fish gelatin adhesive.

Cecum repairs to a backfold.
Cecum repairs to a backfold.

With all repairs complete the six quires and two new vellum flyleaves the manuscript is now ready for resewing. This is a carefully considered operation as the thickness of the vellum, the number of bifolia in each quire, and the dimensions of the manuscript all play a role in determining the weight of both the sewing supports and sewing thread chosen for the job. All the sewing supports have been created in the conservation department using an unbleached linen thread twisted together mechanically to produce the desired product. The position of the sewing supports on the spine will be dictated by the existing holes in the backfolds of the quires, and no new holes will be made in the vellum. The book will be resewn on five flexible double supports which will be laced into the new binding boards, making for a strong mechanical structure. In effect the method used to sew the manuscript will result in a single length of thread running back and forward in the centre of each quire from the front flyleaf to the back flyleaf. This method of sewing mirrors that of the early medieval craftsman at the time when the Book of Dimma was produced in the eighth century.

Linen sewing support and alum tawed leather.
Linen sewing support and alum tawed leather.

The binding boards, traditionally constructed from a hardwood such as oak or beech will in this case be made from a very dense fibreboard laminate made from 100% cotton. This very stable material ensures there is no risk of contamination while being in close contact with the manuscript.

A ‘slotted spine’ of thin vellum will be fitted without adhesive to the back of the sewn manuscript and endbands sewn at the head and tail, with the core of the endbands laced into the new binding boards.

Cotton blue jean board being profiled to fit the manuscript.
Cotton blue jean board being profiled to fit the manuscript.

The manuscript will be covered in alum tawed leather, which strictly speaking is not a true leather being prepared in an aqueous solution of aluminum and potassium sulphates. The end result is a white skin that is very durable, although difficult to work. The process is of great antiquity and many examples can be found still adorning medieval books in libraries around the world.

The binding process will not require the legendary forty days and forty nights it took to write the manuscript but will be carried out in individual stages until complete, the last stage of which will be a new protective box. This approach to the rebinding and choice of materials employed will allow the Book of Dimma to be studied and displayed safely for both scholars and public alike.

John Gillis, Preservation and Conservation Department