With the covers made and stamped and the books sewn, all that remains is is to join the two. The key element in this is the endpaper, which forms the principle hinge, but this is first augmented by pasting a strip of mull, a species of muslin, to the spine, which has first been rounded manually then ‘glued off’ i.e. pasted up and down its length. The books can then be set aside to dry, taking care that they do not stick to one another.
Although I began by rounding, gluing off and mulling before gluing on the endpapers, I soone realise that it made more sense to add the endpapers first. The difference can be seen, I think, in the two piles above. I would judge that the right-hand pile has been mulled first, and the mull has then had to be folded back where it has encroached on the strip next to the spine where the endpaper should be glued – hence the odd angle the mull sticks out at. In the left-hand pile, the mull sits more naturally, suggesting it has been applied with the endpapers already in place. In the bottom picture, the endpapers have been glued on, but the mull has yet to be applied.
And so at long last we come to casing-in… here is an edited version of the final process, which my notes tell me took around 7′ per book (the cut jumps from pasting the front cover to pasting the back). The initial step is to score the spine with the ‘bone’ folder (actually plastic) to allow it to be bent into a curve to receive the book. Next, the book is rounded with thumb pressure.
Observe that disaster is narrowly averted – now that the covers are stamped, there is a right and a wrong way up, and fortunately I check that the book is in the right orientation – it isn’t! The role of the greaseproof paper is first to allow paste to be liberally applied without troubling about going over the edge; then a clean sheet (doubled over) is inserted to prevent any possibility of the endpapers sticking together.
And with every repetition, the piles of books grow…