The book is first removed from the cover. The first signature is then turned back and threads cut with a sharp knife. Generally this will loosen the signature so that it can be separated easily from the rest of the volume. If it is still held by glue and there is danger of injuring the back of the signature, a bone folder is used. If the book had a tight back and the leather, back-lining paper and glue form a very firm back not easily separated in the manner described, the glue may be softened with paste or warm water, with care necessary to prevent the dampness from penetrating the book.
2. Collation
The book should then be collated. The best library binders make themselves responsible for page collation but they do not bother to see that all plates, illustrations, maps, etc., which may be called for by the table of contents, are in proper place. In the case of periodicals they do not always discover the fact that certain parts, not included in the main paging, are missing. Their collation is that of main paging only. Periodicals must, therefore, have title page, table of contents and index in their proper places. Books with two or more main pagings or many unpaged illustrations must be collated at the library. (See Preparing for the bindery, [p. 125.])
3. Knocking Down
(a) Backs of signatures are then pounded down so that they may be as nearly as possible the same thickness as the front of the signatures. Care must be taken to have a clean hammer and to let it fall evenly on the paper. If the backs are not properly pounded down there is likely to be too much swell in the back of the book when it is finally sewed. In all the first processes of binding the question of undue swelling of the back must be taken into consideration.
(b) If the book must be overcast when it comes to be sewed, the back is not only pounded down at this stage, but it is also put under the knife and entirely cut off, leaving single leaves instead of folded sections. If it is not pounded it cannot be cut properly. The success of overcasting depends largely on the amount of margin at the back, so that care must be taken not to cut more than is absolutely necessary.
4. Mending
Leaves are mended with thin tough paper. The librarian should not, however, expect binders to mend books which have a large number of torn leaves without making an extra charge.
Books which are to be overcast and which have had the backs cut off are slightly glued to hold the leaves together. A sufficient number can then be taken off and handled as a section without coming apart.