Rebacking Full Leather Bindings

Rebacking is a treatment typically performed when the text block has broken at the joint in the following three ways: where the endpapers fold, where the boards are connected to the text block (linen or mull spine liner in cloth bindings and the cords that lace on boards in leather bindings), and the cover material. Rebacking consists of constructing a new spine piece out of durable/flexible paper, and using it to reattach the text block and boards so the book can function properly.
To illustrate the process with full leather bindings, I selected four dictionaries from the collection at Syracuse which needed rebacking. All front covers were detached from the text block, and about half of the back covers. Spines had split away from the covers and had several bits missing and all the endbands cracked and coming away from the text block. The following images depict this condition.

 

The first step is to clean and reline the spines. I removed the old covers, spines and broken endbands. Using silicon release paper lined boards, I cleaned each spine with methyl cellulose, being mindful of the raised cords. When the spine was clean, I lined the entire spine with Japanese tissue. Since it is necessary for the cords to remain uncovered, I wanted to practice with two main methods of attaching the linen lining. For two books, I cut the linen into strips the exact distance between the cords, and lined each section between cords and at the head/tail. This took much longer, but laid flatter. For the other, I cut one long strip of linen, and then cut out spaces for each cord, which was faster, but bunched and wrinkled by the shoulder. Once the linen was attached I began resewing the endbands. Due to the large size of these books (approximately 18" tall), I had to move from the bench to the board shear to get the right height for sewing.

When the endbands were completed I began preparing the spine pieces. For leather bindings, PC4 paper is used. It is a heavyweight paper, which is toned with methyl cellulose and acrylics. PC4 paper is relatively flexible when damp, but dries rather hard, functioning as the spine and the stiffener. The PC4 paper is cut into strips the length and width of the spine, accounting for turn-ins, and is parred at the edges. In order to fit tightly over the cords, the prepared spine piece must be molded. This is done using a finishing press (with screws along the sides) and cords. The PC4 paper must be dampened and placed in position. When this is done cords are wrapped around the raised cords of the spine, and secured at the screws like so:

While the spine pieces were drying, I worked on lifted the endpapers and leather on the covers. I then began re-attaching the boards to the text blocks via the linen. First I placed a sheet of waste paper and silicon release paper under the linen. Next, I glued out the linen (PVA) and removed the waste sheet. Then I  placed the covers on so the linen would stick to the board where the endpaper was lifted away, and kept the book closed to dry. Once it was dry, I began attaching the PC4 spines.
I began by putting the spine piece in position. I work with the book flat on the bench so the spine piece is weighted down by the text block. I glued out the board underneath the lifted leather (PVA) and continuously pressed down the PC4 paper until it stuck. Then I placed silicon release paper between the PC4 paper and the lifted leather (to prevent moisture from being introduced to the leather too soon), and flipped the book over to dry under the weight of the text block. I did this to all four books, then repeated the process with the other side. Then I glued down the lifted leather (PVA). Once all the spine pieces were attached to both covers, I glued down the head and tail turn-ins. When those had dried, I glued down the lifted endpapers (PVA), and then covered the hinge with a strip of Japanese tissue (paste).
After all the inside hinge repairs were done, I glued the remaining original spine pieces to the new PC4 spine (PVA) and consolidated the leather with Klucel G. Next I repaired the corners and put Japanese paper along the leather at the joint and along the edges of the original spine pieces. I used two different methods for this as well. On two books I used morike (top), which had to be cut to shape with a water pen, but was already a similar color and therefore easier to tone. On the other two I used dry tear strips (bottom), which allowed for fast and easy application, but proved more difficult to tone. Finally, I rubbed some SC 6000 over the joints to add some shine to the toned Japanese tissue and prevent the acrylic from cracking with use (Winter 2009).