In the case of library binding, however, the books are always sewed by hand and the sewer, as she draws the thread tight, is obliged to use some strength; for this reason tensile strength is an important attribute. Hayes' Irish linen thread is generally specified. The Barbour thread is referred to by Mr. Dana and by others, but the writer is not familiar with its use.
Other materials used in binding are gold leaf, paper for end papers, tape, headbands, cord and various concoctions used in finishing the books. Gold leaf should be 18 to 22 karat, and neither aluminum nor silver leaf should be used. Paper for end papers will vary somewhat with the size of the book, but should never be lighter in weight than a 60-pound manila. Large libraries may find it desirable to have an end paper specially made for their own use. Tapes should be linen and not over three-eighths of an inch wide. Cord for use in sewing in the regular way (not overcasting) is a soft twine which can be obtained from all dealers in bookbinding supplies. For all books less than twelve inches in height use four-ply cord; for larger books, five-ply.
After the librarian has definitely decided upon the binder whom he wishes to employ he must, especially in dealing with binders who are not accustomed to library work, draw up specifications as to ways in which he wishes different classes of books bound. If he has employed a binder who thoroughly understands library binding, he may make use of the binder's knowledge in drawing up the specifications. Under certain circumstances it may be wise to enter into a contract with the binder, but ordinarily in the United States such a course will not be necessary. After the specifications have been prepared and a schedule of prices agreed upon, the librarian always has the right to refuse to pay for books not bound according to specifications. Therefore, a definite legal contract is not necessary. The librarian, except in the case of a few libraries which according to law must give their work to state officials, is always at liberty to take his custom from one binder and give it to another. Thus sufficient pressure is brought to bear on the binder.
Although the present chapter gives definite specifications for the binding of various classes of books, it is always wise to show a certain latitude in the use of specifications. Local conditions, the papers used in bookmaking which seem to become poorer and poorer with each succeeding year, and the kind of a library which is to use the specifications--all these must be taken into consideration when specifications are drawn up. Moreover, the best specifications will accomplish little if they are not followed by the binder in a workmanlike manner, while good workmanship will sometimes make up for omission of important details in the specifications.