Some papers stretch very much when pasted, and will need to be cut a little smaller than needed, and put down promptly after pasting. Thin vellum may be put down with paste in which there is a very little glue, but thicker vellum is better put down with thin glue. In pasting vellum, very great care is needed to prevent the brush-marks from showing through. If the vellum is thin, the board must be lined with white or toned paper with a smooth surface. This paper must be quite clean, as any marks will show through the vellum, and make it look dirty.
When one side is pasted down the book can be turned over without shutting the board, and the other board opened and pasted down in the same way (see fig. 117, B). In turning over a book, a piece of white paper should be put under the newly-pasted side, as, being damp, it will soil very readily. When both ends have been pasted down the joints should be examined and rubbed down again, and the book stood up on end with the boards open until the end papers are dry. The boards may be held open with a piece of cardboard cut as shown at fig. 71.
If there are cloth joints they are put down with glue, and the board paper is placed nearly to the edge of the joint, leaving very little cloth visible.
In the process of finishing, the boards of a book will nearly always be warped a little outward, but the pasted end papers should draw the boards a little as they dry, causing them to curve slightly towards the book. With vellum ends there is a danger that the boards will be warped too much.
OPENING NEWLY BOUND BOOKS
Before sending out a newly bound book the binder should go through it, opening it here and there to ease the back. The volume is laid on a table, and the leaves opened a short distance from the front, and then at an equal distance from the back, and then in one or two places nearer the centre of the book, the leaves being pressed down with the hand at each opening. If the book is a valuable one, every leaf should then be turned over separately and each opening pressed down, beginning from the centre and working first one way and then the other. In this way the back will be bent evenly at all points. When a book has been opened, it should be lightly pressed for a short time without anything in the joints.
If a book is sent out unopened, the first person into whose hand it falls will probably open it somewhere in the centre, bending the covers back and "breaking" the back; and if any leaves chance to have been stuck together in edge-gilding, they are likely to be torn if carelessly opened. A book with a "broken" back will always have a tendency to open in the same place, and will not keep its shape. It would be worth while for librarians to have newly bound books carefully opened. An assistant could "open" a large number of books in a day, and the benefit to the bindings would amply compensate for the small trouble and cost involved.
CHAPTER XVIII
Clasps and Ties--Metal on Bindings
CLASPS AND TIES
Some books need to be clasped to keep the leaves flat. All books written or printed on vellum should have clasps. Vellum unless kept flat is apt to cockle, and this in a book will force the leaves apart and admit dust. If a book is tightly wedged in a shelf the leaves will be kept flat, but as the chance removal of any other book from the row will remove the pressure, it is much better to provide clasps for vellum books.
Very thick books, and those with a great many folded plates, are better for having clasps to prevent the leaves from sagging. As nearly all books are now kept in bookshelves, and as any projection on the side of a book is likely to injure the neighbouring volume, a form of clasp should be used that has no raised parts on the boards.
[Illustration: FIG. 118.]
At fig. 118 is shown a simple clasp suitable for small books with mill-board sides, with details of the metal parts, made of thick silver wire below. Double boards must be "made," and the flattened ends of the silver catch inserted between the two thicknesses, and glued in place. About one-eighth of an inch of the end should project.
In covering, the leather must be pierced and carefully worked round the catch. To make the plait, three strips of thin leather are slipped through the ring, and the ends of each strip pasted together. The three doubled strips are then plaited and the end of the plait put through a hole in the lower board of the book about half an inch from the edge, and glued down inside. A groove may be cut in the mill-board from the hole to the edge before covering, to make a depression in which the plait will lie, and a depression may be scooped out of the inner surface of the board to receive the ends.
At fig. 119 is a somewhat similar clasp with three plaits suitable for large books. The metal end and the method of inserting it into wooden boards are shown below. The turned-down end should go right through the board, and be riveted on the inside. When the three plaits are worked, a little band of silver may be riveted on just below the ring.
[Illustration: FIG. 119.]
A very simple fastening that is sometimes useful is shown at fig. 77.
A very small bead is threaded on to a piece of catgut, and the two ends of the gut brought together and put through a larger bead. The ends of the gut with the beads on them are laced into the top board of the book, with the bead projecting over the edge, and a loop of gut is laced into the bottom board. If the loop can be made exactly the right length, this is a serviceable method.
Silk or leather ties may be used to keep books shut, but they are apt to be in the way when the book is read, and as hardly anybody troubles to tie them, they are generally of very little use.
METAL ON BINDINGS
Metal corners and bosses are a great protection to bindings, but if the books are to go into shelves, the metal must be quite smooth and flat. A metal shoe on the lower edge of the boards is an excellent thing for preserving the binding of heavy books.
Bosses and other raised metal work should be restricted to books that will be used on lecterns or reading desks. The frontispiece is from a drawing of an early sixteenth-century book, bound in white pigskin, and ornamented with brass corners, centres, and clasps; and at page 323 is shown a fifteenth-century binding with plain protecting bosses.
On this book there were originally five bosses on each board, but the centre ones have been lost.
Bindings may be entirely covered with metal, but the connection between the binding and the book is in that case seldom quite satisfactory. The most satisfactory metal-covered bindings that I have seen are those in which the metal is restricted to the boards. The book is bound in wooden boards, with thick leather at the back, and plaques of metal nailed to the wood. The metal may be set with jewels or decorated with enamel, and embossed or chased in various ways.
Jewels are sometimes set in invisible settings below the leather of bindings, giving them the appearance of being set in the leather. This gives them an insecure look, and it is better to frankly show the metal settings and make a decorative feature of them.
CHAPTER XIX
Leather
LEATHER
Of all the materials used by the bookbinders, leather is the most important and the most difficult to select wisely. It is extremely difficult to judge a leather by its appearance.
"We find now, that instead of leather made from sheep, calf, goat, and pigskins, each having, when finished, its own characteristic surface, that sheepskins are got up to look like calf, morocco, or pigskin; that calf is grained to resemble morocco, or so polished and flattened as to have but little character left; while goatskins are grained in any number of ways, and pigskin is often grained like levant morocco.
So clever are some of these imitations, that it takes a skilled expert to identify a leather when it is on a book."
There have been complaints for a long time of the want of durability of modern bookbinding leather, but there has not been until lately any systematic investigation into the causes of its premature decay.
By permission, I shall quote largely from the report of the committee appointed by the Society of Arts to inquire into the subject. There are on this special committee leather manufacturers, bookbinders, librarians, and owners of libraries. The report issued is the result of an immense amount of work done. Many libraries were visited, and hundreds of experiments and tests were carried out by the sub-committees. There is much useful information in the report that all bookbinders and librarians should read. The work of the committee is not yet finished, but its findings may be accepted as conclusive as far as they go.
The committee first set themselves to ascertain if the complaints of the premature decay of modern bookbinding leather are justified by facts, and on this point report that:--
"As regards the common belief that modern binding leather does decay prematurely, the sub-committee satisfied themselves that books bound during the last eighty or hundred years showed far greater evidence of deterioration than those of an earlier date. Many recent bindings showed evidence of decay after so short a period as ten, or even five years. The sub-committee came to the conclusion that there is ample justification for the general complaint that modern leather is not so durable as that formerly used. To fix the date of the commencement of this deterioration was a difficult matter; but they came to the conclusion that while leather of all periods showed some signs of decay, the deterioration becomes more general on books bound after 1830, while some leathers seem to be generally good until about 1860, after which date nearly all leathers seem to get worse. The deterioration of calf bindings at the latter end of the 19th century may be attributed as much to the excessive thinness as to the poor quality of the material."
The committee endeavoured to ascertain the relative durability of the leathers used for bookbinding, and after visiting many libraries, and comparing bindings, they report as follows:--
"As to the suitability of various leathers, the sub-committee came to the conclusion that of the old leathers (15th and 16th century), white pigskin, probably alum 'tanned,' is the most durable, but its excessive hardness and want of flexibility renders this leather unsuitable for most modern work. Old brown calf has lasted fairly well, but loses its flexibility, and becomes stiff and brittle when exposed to light and air. Some of the white tawed skins of the 15th and 16th century, other than white pigskin, and probably deerskin, have lasted very well. Some 15th and 16th century sheepskin bindings have remained soft and flexible, but the surface is soft, and usually much damaged by friction. Vellum seems to have lasted fairly well, but is easily influenced by atmospheric changes, and is much affected by light. Early specimens of red morocco from the 16th to the end of the 18th century were found in good condition, and of all the leathers noticed, this seems to be the least affected by the various conditions to which it had been subjected. In the opinion of the committee, most of this leather has been tanned with sumach or some closely allied tanning material. Morocco bindings earlier than 1860 were generally found to be in fairly good condition, but morocco after that date seems to be much less reliable, and in many cases has become utterly rotten. During the latter part of the 18th century it became customary to pare down calf until it was as thin as paper. Since about 1830 hardly any really sound calf seems to have been used, as, whether thick or thin, it appears generally to have perished. Sheepskin bindings of the early part of the century are many of them still in good condition. Since about 1860 sheepskin as sheepskin is hardly to be found. Sheepskins are grained in imitation of other leathers, and these imitation-grained leathers are generally found to be in a worse condition than any of the other bindings, except, perhaps, some of the very thin calfskin. Undyed modern pigskin seems to last well, but some coloured pigskin bindings had entirely perished. Modern leathers dyed with the aid of sulphuric acid are all to be condemned. In nearly every case Russia leather was found to have become rotten, at least in bindings of the last fifty years."
On the question of the causes of the decay noticed and the best methods of preparing leather in the future, I may quote the following:--
"The work of a sub-committee, which was composed of chemists specially conversant with the treatment of leather, was directed specially to the elucidation of the following points: an investigation of the nature of the decay of leather used for bookbinding; an examination of the causes which produced this decay; a research into the best methods of preparing leather for bookbinding; and a consideration of the points required to be dealt with in the preservation of books.
"Taking these points in order, the first one dealt with is the question of the nature of the decay of leather. To arrive at their conclusions on this subject, the sub-committee made a number of tests and analyses of samples of decayed leather bookbindings, as well as of leathers used for binding. The committee found that the most prevalent decay was what they term a red decay, and this they think may be differentiated into old and new, the old red decay being noticeable up to about 1830, and the new decay since that date. In the old decay, the leather becomes hard and brittle, the surface not being easily abraded by friction. The older form is specially noticeable in calf-bound books, tanned presumably with oak bark. The new form affects nearly all leathers, and in extreme cases seems absolutely to destroy the fibres. Another form of deterioration, more noticeable in the newer books, renders the grain of the leather liable to peel off when exposed to the slightest friction. This is the most common form of decay noted in the more recent leathers. In nearly all samples of Russia leather a very violent form of red decay was noticed. In many cases the leather was found to be absolutely rotten in all parts exposed to light and air, so that on the very slightest rubbing with a blunt instrument the leather fell into fine dust....
"The second point is the cause of the decay. An extensive series of experiments was carried out with a view of determining the causes of the decay of bindings. The sub-committee find that this is caused by both mechanical and by chemical influences. Of the latter, some are due to mistakes of the leather manufacturer and the bookbinder, others to the want of ventilation, and to improper heating and lighting of libraries. In some cases inferior leathers are finished (by methods in themselves injurious) so as to imitate the better class leathers, and of course where these are used durability cannot be expected. But in the main the injury for which the manufacturer and bookbinder are responsible must be attributed rather to ignorance of the effect of the means employed to give the leather the outward qualities required for binding, than to the intentional production of an inferior article.... Leathers produced by different tanning materials, although they may be equally sound and durable mechanically, vary very much in their resistance to other influences, such as light, heat, and gas fumes.
"For bookbinding purposes, the sub-committee generally condemn the use of tanning materials belonging to the catechol group, although the leathers produced by the use of these materials are for many purposes excellent, and indeed superior. The class of tanning materials which produce the most suitable leather for this particular purpose belong to the pyrogallol group, of which a well known and important example is sumach. East Indian or 'Persian' tanned sheep and goat skins, which are suitable for many purposes, and are now used largely for cheap bookbinding purposes, are considered extremely bad. Books bound in these materials have been found to show signs of decay in less than twelve months, and the sub-committee are inclined to believe that no book bound in these leathers, exposed on a shelf to sunlight or gas fumes, can ever be expected to last more than five or six years.
Embossing leather under heavy pressure to imitate a grain has a very injurious effect, while the shaving of thick skins greatly reduces the strength of the leather by cutting away the tough fibres of the inner part of the skin. The use of mineral acids in brightening the colour of leather, and in the process of dyeing, has a serious effect in lessening its resistance to decay. A good deal yet remains to be learned about the relative permanency of the different dyes."
On analysis free sulphuric acid was found to be present in nearly all bookbinding leather, and it is the opinion of the committee that even a small quantity of this acid materially lessens the durability of the leather.
"It has been shown by careful experiment, that even a minute quantity of sulphuric acid used in the dye bath to liberate the colour is at once absorbed by the leather, and that no amount of subsequent washing will remove it. In a very large proportion of cases the decay of modern sumach-tanned leather has been due to the sulphuric acid used in the dye bath, and retained in the skin. We have examined very many samples of leather manufactured and sold specially for bookbinding purposes, from different factories, bought from different dealers, or kindly supplied by bookbinders and by librarians, and have found them to contain, in a large number of cases, free sulphuric acid, from 0.5 up to 1.6 per cent."
The publication of the report should tend to fix a standard for bookbinding leather. Hitherto there has been no recognised standard.
Bookbinders have selected leather almost entirely by its appearance.
It has now been shown that appearance is no test of durability, and the mechanical test of tearing the leather is insufficient. Sound leather should tear with difficulty, and the torn edges should be fringed with long, silky fibres, and any leather which tears very easily, and shows short, curled-up fibres at the torn edges, should be discarded. But though good bookbinding leather will tear with difficulty, and show long fibres where torn, that is in itself not a sufficient test; because it has been shown that the leather that is mechanically the strongest, is not necessarily the most durable and the best able to resist the adverse influences to which books are subject in libraries.