FOUR ESSAYS ON DOUBLE FAN PERFECT BINDING by
Susan Angebrannt Nick Cowlishaw Pete Jermann & Jana Pullman
The Millrind Press
I have put this volume together as a fairly good representation of all that has been usefully placed on the Internet about the latest development in paperback bookbinding. The first article is the earliest and, as the author confesses, has one major point which has since proved to be inaccurate. It always endears me to a writer who not only can freely admit to his past mistakes but also takes proper further steps to correct them. There is no doubt that the methods described seem to be purely craft based. I know for a fact that the only difference between these processes and fully commercial ones is that the commercial ones are fully mechanised but in the various steps taken, they are identical. Sometimes, through misalignment or lack of oversight of the machines, commercial methods sometimes go wrong. Hand methods however call for greater observation at each stage and although slower in execution they may prove as reliable, or even more reliable in the long run. John Kay
Text printed in Stempel Garamond 11pt. and Clarendon
The Millrind Press
Author's note: I wrote this about 14 years ago. As time passes so do ideas and understanding. If I wrote this today it would have more qualifications and a much greater expansion on what exactly happens at the glue line. My conclusion, shown in figure 6 regarding the elastic gutter joint is simply wrong. I would encourage you to read my "Reflections on Book Structures" to see what really happens in the gutter joint. That said I believe there is sufficient food for thought that this article remains worth reading. The binding discussed herein has had thousands of iterations as bound periodicals and monographs in the university library where I worked. It has been a very successful binding, particularly with uncoated papers. Minor problems (single page failures) with uncoated paper have lead to further experimentation, improved success, and ideas that I have expressed in my "Reflections" articles. (7/9/08)
Flexible Strength: The adhesive Quarter-joint binding by Pete Jermann (Originally published in New Library Scene, August 1994) Polyvinly acetate (PVA) adhesives have largely replaced sewing as a means of leaf attachment in modern library binding. PVA adhesives not only secure one leave to another but introduce signficant elasticity at the point of leaf attachment. The elasticity provides a dynamic that suggests a binding strategy entirely different from that used for sewn books. The adhesive quarter-joint binding, 3
described in this paper, attempts to maximize the benefits of this elasticity by combining flexible and elastic modern PVA adhesives, strong thin spine linings, a redesigned endsheet and an appropriate casing technique to create a book that opens perfectly flat (figure 1). This ability to open flat, in turn, effectively neutralizes many of the problems normally associated with the binding of heavy papers or cross-grain papers. The adhesive quarter joint binding is suitable for leaves that range from normal book paper, to heavier paper stocks, to board or any combination thereof. It is particularly suitable for heavier papers and books of mixed paper weights, such as journal accumulations bound together with their heavier covers intact. In the adhesive quarter-joint binding I have tried to achieve a binding that is at rest on the shelf and in use. This state of rest distinctly contrasts with the near perpetual state of stress found in traditional bindings. The possibilities inherent in an adhesive bound quarter-joint binding require an understanding of strength and stress in bookbinding and the modifications necessary to achieve an ideal combination of the two. In the ensuing essay I submit my understanding of these topics, how they relate to a book's structure, the construction of adhesive-bound quarter-joint binding and how it resolves the stress and strain found in traditional binding.
Absolute vs. Relative Strength A book breaks down when stress exceeds strength. A book's strength is not a constant but a value that tends to decrease with time and use. At some point in time stress exceeds strength and damage occurs. We can measure strength in absolute or relative terms. The strength of a book's leaf attachment is traditionally measured with a page pull test. This test simply exerts an ever increasing pulling force on a single page within a book until the page separates from the book. The measure of the force in pounds or kilograms required to separate the page from the book is a measure of the absolute strength of this attachment. Our initial inclination is to regard higher ratings as good 4
and lower ratings as less so. A book whose page attachment offers the highest pull rating will always be less likely to break down than a book whose pages are more readily detached. The equivocal truth, however, is that it depends. It depends on the overall structure of the book. Relative strength measures strength in the context of the environment in which that strength exists. The oak tree and the blade of grass provide a natural example of the concepts of absolute and relative strength. The oak tree stands firm and resistant in a stiff wind. It will give within limits, but once the wind exceeds those limits it will uproot or break. A blade of grass in the same wind will simply yield. Should the wind persist it will bend flat to the ground and let the wind pass. When the wind stops, the blade of grass will resume its former upright position. Nobody doubts that an oak tree is stronger than a blade of grass, yet the ability of the grass to reduce its profile to the wind allows it to minimize the stress of the wind and survive the storm without the strength of the oak. A book can be like the oak tree. Just as the oak tree will only lie flat after it has broken, so only by breaking will the book succumb fully to the photocopy machine. A book, however, can also be like the blade of grass. Just as the grass gives to the wind so a book can give to the photocopy machine. The strength of the first book is unmatched by the second book - yet one survives and one doesn't. Relative strength recognizes that the stress on a book varies with a book's structure. A page that can resist up to 15 pounds of pull is useless in a book that exerts 20 pounds of pull when the book is opened. That anybody would design such a book seems inherently ridiculous. The reality, however, is that we have all experienced the "perfect" binding whose pages break loose with the first opening. In these bindings the strength of the page attachment is less than the structural stress exerted by the book's opening. Another book could have pages capable of resisting only 10 pounds of pull. If the opening of the book, however, only exerted one pound of pull on the pages, the strength of the page attachment would be more than adequate by a factor of 10. The concept of relative strength recognizes that 5
the latter book is more durable than the former even though the absolute strength of the page attachment is less. Relative strength is the ratio of absolute strength over stress. If the ratio is one then stress and strength are equal and the book will be stable only until an increase in stress or a decrease in strength occurs. Where the ratio is less then one, as in the first example above (15 lb. strength/20lb. stress = .75), the book will fail. In the second example the ratio of 10 (10 lb. strength/1 lb. stress) allows a wide latitude for increase in stress or decrease in strength. The higher the ratio the more likely the book's survival. This statement assumes several arguable premises which I will state as fact for the time being. These premises are: 1) the major stresses on a book at the point of leaf attachment are inherent to the book's structure, and 2) unless a page is willfully removed, page separations are usually the result of internally transmitted stresses that overtime have either weakened page attachment or damaged the book's structure such that stress becomes concentrated at the point of leaf attachment. Improving book design based on absolute strength means increasing the strength of the component parts. Improving book design based on the concept of relative strength gives the designer two paths. He/she may increase the strength or decrease the stress inherent within the book structure. A move in either direction can increase the relative strength of the book. Whereas much has been done with traditional bindings to increase their absolute strength, less has been done to decrease the stress. My quest was to follow the latter path.
The Stressed-out Book Unless lying closed on its side, the traditional hard bound book is in a constant state of stress. This stress begins when the book is first shelved. The practice of squares on the bottom edges of a book cause the textblock to hang from its case when the book is standing upright. A square is the slight extension of the book's cover beyond the textblock on the top, bottom and front edges. The inclusion of a bottom square lifts the textblock off of the shelf and places the weight of the textblock on the joints where the cover meets the spine. Under such circumstances the textblock tends to lurch forward out of the case. This tendency can be counteracted bylining and reinforcing the spine to help it maintain its shape (increasing the strength) and by rounding and shaping the spine to help lock it into the case. Over time, however, the spine will lose its shape and the joints will tend to loosen. When the book is removed from the shelf and laid open the very liners that reinforce the spine in its vertical shelved position create a structure resistant to the book's opening (fig. 2 and fig. 3). The glue and other materials that may line the spine (cloth, paper, cords, tape, leather, etc.) create a laminate structure whose tendency is to hold the original convex shape in which it was formed. This laminated structure resists the natural tendency of the pages to open to a flat or gravity neutral position (the curvature to which the pages would naturally fall if not attached to the spine). With traditional materials and techniques the resistance of the spine is desirable. Traditional hide glues of limited flexibility dictate a spine of limited mobility. The use of sewn-on cords and tapes to secure boards to the textblock not only inhibit the motion of the spine but demand limited motion to protect the tapes, cords and sewing. These structures require that a quality book open such that the spine rises slightly in a gentle concave arc (as depicted in fig. 2). A spine that breaks this pattern and opens into an inverted vee not only threatens to stress the glue beyond its elasticity but also puts undue stress on the sewing, the cords and the leaf attachment. 7
When a book is opened the pages tend to rise toward a flat or planar position at the point of opening. This creates an upward pull (A). As the book rises at the point of opening there is a corresponding movement (C) of the joints (the junction of the textblock spine and the case) toward the center. The spine on the traditional case bound book contains two laminated structures. The layers on the spine of the textblock composed of the glue, super (and/or cords, tapes, etc.) and paper liner(s) make up one laminated structure. The layers on the case spine made of the cover material (cloth, leather or paper), the inlay (a piece of heavy paper or bristol), and the cover material turn overs at the head and tail of the book make up the second laminate structure. It is the nature of laminated materials to retain the shape in which they were formed and to resist changes to this original shape. The laminated spine of the textblock whose original shape is convex, resists (B) the upward pull of the pages. The case spine resists (D) the inward pull (C) of the textblock joints. A book that opens in a gentle arc indicates a proper resolution of forces. The problem inherent in such a binding, however, is implied in the very phrase resolution of forces. Such a binding is indeed a resolution of conflicting forces. It is a resolution much like two rams butting heads with equal force. Though each ram may be pushing with all his might it may appear the rams are simply standing head to head. Such is the illusion of the traditional book. The gentle concavity of the spine is not a book at rest, but a momentary resolution between the upward thrust of the pages and the resistance of the spine to any change in shape. The upward thrust of the pages is caused 8
by the individual pages pulling at the point of leaf attachment as they try to achieve a state of rest. Just as the resistance of the spine can vary with different types of linings and sewing constructs, so can the upward thrust of the pages vary with the type of paper. Stiff or cross-grained papers exert greater pull than papers that drape well. Papers that don't slide easily across one another, due to cockling, static induced adhesion or other factors, will tend to have a cumulative effect that can exert a significant pull on the pages at the center of the opening. This illustrations represent books made of binder's board to illustrate the effect of linings on the textblock spine. Each book was allowed to fall open without the leaves being forced flat. A) 1 cotton liner - book falls into a fully open position. B) 2 cotton liners - book resists opening flat C) 1 cotton liners, 2 100 lb. paper liners - increased layers add increased resistance to opening Whereas convention esteems the book whose spine opens to a gentle concave arc, it conversely disparages the book whose spine opens to an inverted vee (fig. 4). The former opening distributes stress, the latter concentrates it, often with damaging results. Given the traditional cloth and paper (and cords or tapes) laminate such indeed will be the case. An inverted vee opening has two effects (fig. 5). First it damages the laminated spine structure by causing a delamination at the apex of the vee. This delamination usually occurs within the paper liner rather than between the paper and cloth liners 9
and becomes a weak point in the spine's structure. This weakness will exhibit itself as memory point to which the book will readily fall open. Secondly, the fold at the vee's apex represents a doubling of the paper-cloth laminate which tends to pull the pages apart at that point. In a sewn book this tends to pull on the sewing local to the point of stress and contributes to its loosening.
We can inhibit the motion of the spine by strengthening it with stronger or additional reinforcing materials. This very strengthening, however, increases the potential for damage when the book is actually used. The thicker the laminate or built up spine structure the greater the damage to the book should the spine be forced into a vee shaped opening (as is likely to happen when photocopied). Anything that adds to the effective thickness of the textblock spine, such as tapes, sewn on cords, oversewing, sidesewing, notch binding, or particularly deep fan gluing, limits the movement of the spine and increases internal structural stresses. A method such as side-sewing, where a book is sewn through the gutter margin, creates an effective spine thickness of 1/4 to 1/2 inch and limits the motion of the spine absolutely. The strength, both relative and absolute, of sidesewn bindings is substantial but the cost of that strength is a high degree of inherent stress. This stress manifests itself in the need for great external force to keep the book open for reading or the frequent full body press placed on such a book at the photocopy machine.
The liners which make up the layered spine affect a book's ability to open flat. A properly lined spine will allow a book to open flat without structural damage. The photo illustrations to the right are closeups of books made of binder's board. These board books were purposely made to exaggerate the stress of opening to clearly show the effect of the number of layers or of the thickness of the structure lining the spine. A) 1 cotton liner - the book opens flat without being forced. The spread between the two open halves is minimal. B) 1 cotton liner, 2 100 lb. paper liners the book had to be forced into a flat open position. The spread between the two blocks becomes wider with the edges of the board beginning to pull away from the cloth liner. Though not visible in the photo, the paper liners have started to delaminate. C) 1 cotton liner, 4 100 lb. paper liners the book had to be forced into a flat open position. The spread between the two blocks is such that one board is almost completely detached by the act of opening the book. The liners quite visibly have begun to delaminate under the stress of opening. Though books are seldom so heavily lined, the impact of a sewn on raised cord would be similar or greater. 11
The action of the book's cover or case further exacerbates the stress found in the interaction between the laminated spine structure and pages. Should the book be a tight back design, the covering material (usually leather) adds another layer of lamination to the spine and increases the aforementioned effects. a modern hollowback design adds different stresses. The spine structure on the case consisting of the cover material, the inlay, and the cover material's turnovers creates yet another laminated structure resisting change. this structure effectively keeps the outer boards from moving toward each other as they are wont to do when a book is opening (fig. 2). This resistance creates a pulling on the joints where the cover is attached to the textblock and a pulling across the paper-cloth laminate on the spine of the textblock. The pulling on the paper-cloth laminate further inhibits the motion of the textblock spine, further preventing the pages from reaching a state of flatness or a position of rest. These combined stresses can cause a loosening of the joints and/or delamination of the inlay from the cover material. The action of the book's cover or case further exacerbates the stress found in the interaction between the laminated spine structure and pages. Should the book be a tight back design, the covering material (usually leather) adds another layer of lamination to the spine and increases the aforementioned effects. a modern hollowback design adds different stresses. The spine structure on the case consisting of the cover material, the inlay, and the cover material's turnovers creates yet another laminated structure resisting change. this structure effectively keeps the outer boards from moving toward each other as they are wont to do when a book is opening (fig. 2). This resistance creates a pulling on the joints where the cover is attached to the textblock and a pulling across the paper-cloth laminate on the spine of the textblock. The pulling on the paper-cloth laminate further inhibits the motion of the textblock spine, further preventing the pages from reaching a state of flatness or a position of rest. These combined stresses can cause a loosening of the joints and/or delamination of the inlay from the cover material. 12
The Solution Traditional bindings deal with stress through strength. A well executed traditional binding is strong, durable and suitable to its intended purpose of reading. Today, however, we no longer merely read our books. We subject them to photocopiers, microfilm cameras and digital scanners. Whereas normal reading seldom requires a perfectly flat page, these modern technologies often do. Fortunately, modern materials also give us the means to bind a book that will not only meet the needs of both human and mechanical readers but will also allow us to significantly reduce the internal stresses found in the traditional book. We can design a book that is largely at rest both on the shelf and in use. Standard methods of strengthening are appropriate for the traditional book that is made of signatures, sewn through the fold, glued, lined with cloth and paper, and covered with a hollowback case. Should such a book open completely flat both the signature at the point of opening and the hinge joints are stressed. A structure that limits the motion of the spine to a gentle concave shape prevents this undesirable concentration of stress. Modern bindings composed of single leaves, rather that signatures, and secured with flexible and elastic adhesives are different animals with different strengths and different weaknesses. An adhesive binding can be designed such that the pages lie completely flat when opened. Furthermore, we can virtually eliminate the damaging structural stresses associated with such an opening. Modern adhesives allow us to increase the relative strength of a binding by removing stress rather than increasing strength. The key to reducing stress begins with the ability of a book to open flat without concentrating stress on the point of opening. In a hollowback sewn book whose textblock spine is lined with both cloth and paper liners, two factors contribute to the stress at this point of opening: 1) the structural dynamics of the laminated spine composed of a paper liner, a cloth super and the back of the signatures 13
which effectively create another layer of paper, and 2) the pulling action of the case on the spine liners. The solution to the problem presented by the laminated spine is to reduce stress by reducing the laminations or thickness of the spine structure. This can done in two stages. The first stage eliminates the paper layer created by the backs of the signatures by converting to a binding made of single leaves where the leaves are secured with a properly plasticized PVA. Rather than a continuous expanse of paper crossing the gutter joint, we can now have two individual pages joined at the gutter by an elastic emulsion. This emulsion can stretch to accommodate the slight expansion of the gutter required for a full flat opening and then return to its original dimensions when the book is closed or the page is turned (fig. 6). The Elastic Gutter Joint The full, flat opening of a book causes the gutter joint to spread at the point of opening. When a book is made of single leaves joined with an elastic PVA adhesive, the adhesive (the gray in the enlarged area above) can stretch across the gutter joint as shown at point A. The super (B) unhampered by tapes, cords or a paper liner, simply folds back on itself. Figure 6 The elasticity of the emulsion is limited, however, and can be stressed beyond its limit. The laminated spine structure exerts a spreading force on the gutter as the traditional concave spine action gives way to the inverted vee. The thicker the laminate the greater this tendency. In the second stage of our solution we further reduce the thickness of the laminate. We eliminate the paper liner completely 14
and, instead, rely on a strong, thin (the thinner the better) cloth liner or a liner made of a synthetic material such as polyester. Eliminating the paper liner reduces the thickness of the spine structure and allows the spine to move more freely. The pulling action of the case on the textblock spine represents the final source of stress on the page attachment of the opened book. Redesigning the case so the case spine moves freely and does not resist the opening of the book, eliminates this stress. This is accomplished by broadening the hinge joint on the book's cover to at least 1/4 the thickness of the book and leaving these joints unattached to textblock (see fig. 1)2.* Not only do the loose joints allow for free movement of the spine, they also allow the use of an inflexible inlay in the case spine. This rigid inlay provides a good base for the use of paper labels which tend to crease and delaminate on flexible case spines. At this point, if the adhesive is sufficiently elastic, if the spine is lined with a thin flexible and strong material and if the case offers no resistance to the opening of the textblock, the book should open such that the pages lie flat. As the spine gives completely to the upward thrust of the pages, the pages neither fan open nor pull where they attach to the spine. Rather than the collective stress of many pages attempting to achieve equilibrium, our redesigned book reduces the pull to that of the two pages on either side of the glue line and resolves this minimal stress through the elasticity of the adhesive. To complete our design we must deal with the problems associated with the book standing on the shelf and in transit. The use of squares, as described earlier, creates a situation where the textblock is suspended in the case when a book is vertically shelved. So suspended, the textblock both pulls on the hinge joints and deforms at the spine and foredge as it tries to come to rest on the shelf. A traditional binding counteracts this with a slightly stiffened, reinforced spine, secure hinge joints and a rounded and shaped spine. none of these characteristics are found in our adhesive QUARTER-JOINT binding. We can solve this simply, however, by reducing the squares on the bottom edge of the case such that the textblock can rest on the shelf without 15
straining its attachment to the case. This will remove all or most of the strain on the standing book. A smaller, residual strain on the hinge joints will sometimes exist due to the difficulty of perfectly aligning the textblock with the bottom edge of the case, as well as problems associated with the forward pitch of larger textblocks if the book is loosely shelved. The solution to this problem is the same as the solution to the problem posed by a book in transit. The Stiff Shoulder Joint Since the quarter-joint book's cover or case is not joined to the textblock at the hinge joint, as in traditional bindings, an alternate structure is provided to prevent the textblock from falling forward in the case when the book is carried or loosely shelved. A stiffened endsheet provides this support. The diagram above shows a standard, commercially available endsheet comprised of a folded sheet and a single sheet secured together with a cambric strip which extends about an inch onto the pastedown and about 1/4" onto the flyleaf. This standard endsheet is stiffened by gluing a 5 to 10 mil polyester stiffener (mylar) into the gutter margin of the folded sheet which is then glued closed. This creates a single laminated pastedown comprised of the opposing sheets of the folded sheet and the stiffener. It is important that the stiffener be slightly flexible and resistant to creasing as once it is creased along the joint it will no longer adequately support the textblock. A strip of 5 or 10 mil mylar or an equivalent serves this purpose well. When in transit, a book with loose hinge joints will tend to drop out of the case, particularly when carried in one's hand with the foredge down. A stiffening of the endsheets in the hinge joint area counteracts this problem, as well as any slight forward pitch of the textblock that remains even when the bottom case squares are eliminated. On small, light weight books this stiffening occurs naturally if the spine lining cloth that passes over the spine and is secured to the endsheets is of sufficient weight. Heavier books require an endsheet reinforcing material that offers some flexibility yet a high resistance to creasing. For lack of other available materials, I have found that 5 to 10 mil Mylar offers these capabilities. After a period 16
of trial and error I have arrived at a solution based on a modified commercially available endsheet (fig. 7). Once the endsheets are properly stiffened the completed binding can be handled without any sense of a freely moving textblock. Caveats and Conclusions With every advance into new territory there are possible pitfalls. The adhesive bound, loose quarter-joint binding depends on the quality and longevity of the adhesive used. Its long term survival requires that the emulsion formed on the spine remains elastic and the adhesive bonds durable. Unlike a traditional sewn binding where the sewing provides a fallback once the adhesives on the spine break down, the adhesive bound quarter-joint binding has no such fall back position once the adhesive fails. However, if this problem did occur and was caught before the book became a mess of loose tattered paper, rebinding could be easily accomplished. Though my experience to date has indicated adhesive quarter-joint bindings are durable, I continue to search for a better adhesive and a better spine lining material. Whereas the page pull strength of a sewn binding is the strength of the paper, the page pull strength of an adhesive binding tends to be that of the adhesive. Pages can be peeled from the quarter joint binding with less effort than they can be torn from a sewn binding. The absolute strength of the page attachment is low compared to 17
traditional sewing methods and some other adhesive methods. I would maintain, however, that the relative strength is high and that this high relative strength is more than sufficient for normal use. Abnormal uses, such as willful removal of pages, usually introduce strains which exceed the strength of the paper and render the strength of leaf attachment irrelevant. The action of the loose quarter joint binding differs from that of traditionally bound books. as the reader moves from one point in the book to another, the case spine moves to adjust to these changes. in large, heavy books (1-1/2" to 2-1/2") these adjustments noticeably raise and lower the textblock when the book lies open on a table. Occasionally the case spine catches under the weight of one side of the book and requires some adjustment to bring the textblock back into a state of equilibrium. On smaller volumes this movement of the case spine is not particularly noticeable. To date these problems appear minor. I have submitted hundreds of adhesive bound quarter-joint bindings to the rigors of use in the real world of an academic library. Over the past year I have purposely selected books for their high usage. I have bound the quarterly issues of the Reader's Guide and the quarterly accumulations of heavily used periodicals such as Time, Newsweek, Forbes, Businessweek, Psychological Abstracts, etc. I have pushed the limits beyond thicknesses and weights I normally bind to include volumes up to 2-1/2" thick. I have particularly selected volumes with coated papers. The results so far are promising. The quarterly supplements of the Reader's Guide have survived, somewhat tattered, but still intact when the annual cumulation arrived up to a year later. I have encountered several instances of loose pages in the bound, coated paper, periodical volumes. In most of these cases the problem could be identified as pages that slipped forward in the initial gluing process and were insufficiently attached from the beginning. Of the remaining (2 or 3) the page failure rate appears to be less (though I am honestly only guessing) than the page failure rate in earlier, more traditional fan glued bindings. Several volumes of USA Today, a news magazine (not the daily newspaper), printed on stiff coated paper, had failed 18
in their previous tight backed, quarterbound bindings (fan-glued, with cloth super and F grade buckram glued directly to the spine). To date, the quarter-joint rebindings have survived approximately a year with no sign of failure. Whereas the problems appear minor the advantages of the adhesive bound quarter-joint binding are significant. First, photocopying no longer threatens the book. A book so bound lies perfectly flat on a photocopier's platen without strain . Two page spreads can be photocopied without any depression between the pages. Microfilming and digital scanning gain similar advantages. Second, the drape of a paper, its ability to fall into the gutter, is no longer important. Assuming that edge cockling can be controlled, the grain of the paper is irrelevant. The action of this type of book actually improves with the stiffness of the paper. Loose collections of boxed art plates can be easily consolidated in a adhesive quarter-joint binding with the only intrusion on their original integrity being a line of adhesive equal to the thickness of its bound edge. Heavier card stock and even paperboard materials can be inserted throughout the text without adding any strain to the book when it opens. On particularly thick, heavy books a paperboard insert placed in the middle of the textblock can add additional support to the book as it sits on the shelf. And third (a little more speculative), glossy papers which suffer a high rate of adhesive failure gain in relative strength and achieve a higher rate of survival. The adhesive quarter-joint binding adopts modern materials and attempts to maximize their advantage. It begins an exploration of which book structures are based on material limitations and which are traditions habitually repeated. Further, it seeks to understand the source of a binding's strength. In this exploration the traditional book becomes the oak tree. We expect it to act like an oak tree. We expect it to feel a certain way in our hands. We expect it to resist movement beyond a given point. When a book acts contrary to our ingrained expectations, we deem it weak and unfit. The appearance of weakness, however, can be another type of strength. The book can become the blade of grass where the ability to yield replaces the 19
ability to resist. For this to happen we must rethink our expectations of how a book should act and renew our understanding of a book's dynamics. The adhesive quarter-joint binding is one step in this direction.
Reflections on Book Structures - part 1 by Pete Jermann
Herein I pass on the reflections of an addled, middle-aged guy who spent 23 years working in an academic library binding and repairing books. If you are looking for thoughts on fine binding, you are looking in the wrong place. If you are looking for thought provoking (that means I may well be wrong) concepts related to book structures than read on. My job as preservation officer and bookbinder was to extend the life of the circulating collection through repair and rebinding and to do what I could with the time that actually wasn't left over to keep the rare book collections from deteriorating past their current state. Many of the processes I developed and the thoughts I thought were formed by the pressures of a job where the work always exceeded the resources available. I was also in the unique position where I worked in one of the few libraries, if not only library, in the country at that time (and up through 1999 when I departed) that was still doing much of its own periodical binding in-house. I began as a student in 1976 and learned the basics under Father Joe Ruther, a Franciscan Friar, who had operated the bindery since World War II. We had two processes for binding periodicals. If the periodical was in anything remotely resembling signatures they were sewn through the fold on sawn-in cords. If you are wondering what something remotely resembling a signature is then you need to experience a burst binding where much of the back of the signature is burst to allow glue to penetrate to the inner signatures. Burst signatures leave almost nothing for the sewing thread to hang on to. To my constant frustration Father Joe insisted on treating these as signatures nonetheless. If a periodical was comprised of single pages adhesive bound we would drill through the margin and side-sew the binding. 21
Probably 75% of our binding hours were spent breaking books down into either individual signatures or individual pages and then resewing them, either through the fold or side sewn. After sewing your first five to ten thousand books the therapeutic value of sewing begins to wear off. That warm, fuzzy, back-to-your-roots, proletarian feeling gives way to the thought that there has got to be a better way. When Father Joe was forced into extended periods of medical leave I began to play. Upon returning from his first six weeks leave he found a new glue, PVA, and the rudimentary beginnings of a new process, double fan-gluing. Though he never adopted nor explicitly approved of what I did, he did assure me that he once was a young man also and, as such, had his period of experimentation. From this point on there were now two ways of doing things, his way and my way. Within several years he passed on and the bindery became mine alone for the next 15 years. When I left the bindery in 1999 to stay home with my newest daughter and to tend to TeMPeR Productions I left behind an operation that did very little sewing and lots of fan-gluing. The transition from where I began in 1976 and what I left in 1999 involved much musing, problem solving and major mental shifts. I worked in one place and with one collection long enough to enjoy my successes and to see my failures return to me. From my experience I present below the following often rambling, possibly overstated, and definitely arguable reflections. Please forgive me for a binding history that is at times fast and loose. My sense of binding history is based largely on books that have passed through my hands. It is not my intent to discourse on the history of binding but to use it loosely to illustrate and explain binding structures.
Sewn bindings vs. Adhesive bindings Sewing signatures and gluing single leaves together both solve the single problem of leaf attachment or how to keep the pages together in a book. It is the beginning of the bookbinding process and a single component of the more complex structure that is the finished book. Their success or failure is usually more dependent on the remaining structure of the book than on the original method of leaf attachment. Neither process can lay claim to an inherent superiority over the other. Both come in many variations and both have their successes and failures. With many modern papers either process can be used successfully and if well done, interchangeably. Depending on the paper, some books are better sewn and some are better glued. Experience best determines where that line falls (sorry, there is no easy answer here). With the exception of numerically insignificant no-glue bindings coming out of some conservation shops and comb/spiral bindings, all modern bindings are adhesive bindings whether they are sewn or not. Every commercially sewn binding has been glued up on the spine and lined with some manner of reinforcement, be it paper or cloth. Those who proclaim the superiority of the sewn binding have not been paying attention to the work flow across their benches. Once the adhesive fails in a modern sewn binding the sewing will fail shortly thereafter if use of the book continues. A modern, machine sewn book is a loose affair before the glue consolidates the signatures into a manageable entity. Once the glue fails the sewing becomes a destructive liability as the threads, now free to move, tend to saw the needle holes larger and rip the signatures. Sewn books with slick papers often depend on the tiny bit of glue that has worked its way into the thread holes. Should the glue not penetrate sufficiently, the inner leaves will move, ripping against the entrenched thread. Without the protection of an adhesive, a modern sewn book will not successfully stand. 23
Please note that in matters of sewing I distinguish modern from ancient. Many books survive from the middle ages with their adhesive long gone and their sewing intact. These survivors are raised as examples of the superiority of thread over glue. However, what they actually illustrate is that if you build a book with pages of animal based leaves (parchment/vellum), which are virtually untearable, or of heavy handmade papers using a thick thread combined with handsewing that creates a tight textblock, you can create a durable book based on sewn leaf attachment. However, these books were very expensive, comprised of materials largely unavailable today, not particularly user friendly, producible in small quantities only, and, consequently, only available to a very small and elite group. The ability to make books available and affordable to the masses (that's you and me) depends on the technologies and materials that produce the modern book. Our attempt to produce durable bindings must be built on what actually exists as opposed to wishful thinking based on a past that is no more. Whereas the virtues of sewn books are often uncritically extolled, the defects of adhesive bound books are uncritically broadcast. A poorly done adhesive binding lends drama to its failure in a way a sewn binding does not. Everybody seems to have remembered at least one adhesive bound book that literally burst apart on its first opening while ignoring the intact phone directory that they use repeatedly without failure. Similar to sewn bindings, adhesive binding refers to a broad class of bindings that vary by the type of glue, the manner it which it is applied and by the remaining structure that makes up the bound book. (Note: pet peeve coming up) The use of the term "perfect binding" to refer to all adhesive bound books improperly services any discussion of adhesive binding by imposing negative connotations on adhesive binding. I believe the term "perfect binding" was originally a trademark referring to the very process that produced those dramatically explosive adhesive bound books. Its use to refer to all adhesive bound books provides no useful information and denigrates many well bound books. 24
The truth is that, overall, adhesive binding technology is a major success. After a bad start (i.e. "perfect binding") it has come a long way in reducing costs and putting durable books into the hands of consumers. For every adhesive bound book that fails there is an overwhelming preponderance of those on our shelves that never come to our binderies. Adhesive binding offers the binder a tremendous efficiency in binding over sewing. In a small, unmechanized bindery the process of leaf attachment takes minutes. Many books that are sewn can be just as successfully adhesive bound. However, this is not to say all books should be adhesive bound. It has its limitations and its problems. There are good adhesive bindings and bad adhesive bindings. Books with very thin papers, such as bibles are probably better served by an adhesive binding which grips each individual page along its entire length then by a sewn binding where the inner pages of the signatures tend to slip against the threads. Book on heavy coated papers are best served by a sewn binding. Between these two extremes there are many books well served by either option.
On Sewing Structures The purpose of sewing signatures through the fold is twofold. The first is to secure the gathered pages of a single signature to itself. I refer to this as the intra-signature sewing. The second purpose is to attach one signature to the next, or inter-signature sewing. The two functions, intra and inter-signature, fill structurally distinct roles. Whereas the failure of intra-signature sewing will almost always lead to a binding failure, i.e. loose leaves, the failure of inter-signature sewing is irrelevant in a modern hybrid binding that is both sewn, reinforced on the spine and glued. Glue and super in a modern binding structurally replace the inter-signature sewing. Only when glue and super fail does the inter-signature sewing even come into play and at that point it is probably a danger to the signatures as discussed above.
The inter-signature sewing in a modern, machine sewn textblock is actually quite loose, allowing significant play between signatures. Add glue and the textblock tightens considerably as the adhesive secures the many signatures into a unified textblock. The addition of a super reinforces this. Glue and super remove the play in the textblock, preventing the inter-signature sewing from being extended to the point where it plays any structural role. To prove this point to a conservator friend of mine, I once constructed a sewn binding with no inter-signature sewing. I sewed each signature as a single pamphlet, aligned and clamped the collection of signatures, glued up the spine and, when dry proceeded to round it, back it and bind it as if it were a normal sewn textblock. When I presented her with the finished product without her knowing the details of construction she could not discern any difference between it and a normally sewn binding. Fifteen years later that sample is still intact and functional. So, what is the significance of this structural distinction between inter and intra-signature sewing? Understanding this can significantly simplify repair of a sewn binding as well as offer new options for sewn bindings. If a sewn textblock separates between signatures into one or more blocks, it can be repaired by ensuring that the intrasignature sewing is intact, stacking the various parts neatly, clamping them together, re-gluing and re-lining the textblock. Securing the intra-signature sewing can be as simple as having just enough loose thread emerging onto the spine to be caught and secured by the glue. Also new bindings can be built from a collection of signatures internally secured as noted above.
On supers, sewing supports and endsheets The super, also known as the crash or mull, reinforces the spine and secures the cover to the textblock. Early binders integrated sturdy cords or thongs made of various animal skins into the sewing of the spine. The cords and thongs, apparent on early bindings as raised bumps or bands on the spine of the finished book, extended beyond the spine and were laced or woven into the boards to secure them to the textblock. What we see as the finished binding was then built 26
upon this structural backbone. The tightback construction of early bindings, like the super in modern bindings, further reinforced the board attachment. In the nineteenth century demand for books increased. Filling this demand required faster and cheaper methods. As machine sewing had yet to dawn, binderies streamlined the handsewing process and turned to mass production based on cheap labor. Binderies became factories filled with women inhabiting row after row of sewing racks. These women sewed signatures on cords set into saw cuts on the spine of the textblock. Rather than having to loop the thread around a raised cord, or in a much more intricate pattern around a double raised cord, the thread simply passed behind the now set-in cord. This was much quicker (and, quite arguably, vastly inferior) to the old process. The cords still extended beyond the spine onto the boards. However, by this point in time the importance of lacing the cords to the boards seems to have been forgotten. These books were now casebound, the cover was made independently and attached to the book in a final step rather than built onto the spine/board structure as had been done previously. When case and textblock came together in the final step of the process, the cords were simply splayed out and glued down onto the board between the board and the pastedown. If any, spine reinforcement was minimal (often just a paper lining) and did not extend onto the boards. The mass produced nineteenth century book represents a transition between the modern, machine sewn book and the previous tradition of handcrafted books. The cords were now vestigial appendages. The splayed, glued down connection to the boards contributed little to the actual attachment of the boards and a modern system to replace the laced in cords was yet to come. Essentially, the books depended on their endsheets to secure textblock to cover. These books were bound to fail if they received any significant use. When they did fail it most likely occurred at the junction of the pastedown and endleaf. My guess is that these failures led to generations of binders experimenting with various means of reinforcing the hinge between the pastedown and the end leaf. This is still the principal 27
mode of attack for the novice who attempts to replace a detached cover by taping or by some means re-attaching the cover to the endsheets. Somewhere in the transition from ancient to modern, binders seem to have temporarily lost a key concept: the boards were secured by the cords which were secured to the spine of the textblock. The boards (and the consequent cover) were never secured by the endsheets. The role of the endsheet/pastedown assembly was either aesthetic or a means of controlling warpage in paper based boards. Many early wood board bindings simply omitted them. The endsheets played little or no role in securing the cover to the textblock. Attempts to give the endsheets a structural role represent an evolutionary dead end in binding (there are minor exceptions here - the quarter-joint binding being one). The introduction of the cloth super that extended across the spine and onto the boards reasserted the original principal that a book's boards (and therefore its cover) are attached via the spine. Whereas the early book may have been sewn on anything from two to a dozen or more heavy cords that reached across to the boards, the modern super-reinforced binding has literally hundreds of tiny cords (the threads in the super) that secure adhesively to the spine and reach over to secure the boards. A brief aside: the emphasis on endsheets as a structural component may have been aided by the concept of thongs and cords as sewing supports rather than as a means of board and cover attachment. Eliminate the boards and the concept of "sewing supports" eludes me as I cannot see exactly what is being supported (that wasn't already supported) or what sewing or leaf attachment problem was solved by the addition of cords. I believe that early codex bindings had neither hard covers nor cords but were sewn with a chain stitch connecting one signature to the next. My unsupported speculation is that the evolution of sewn-on cords and thongs was directly related to attempts to figure out how to get those darn boards (or even soft covers) to stay attached to the textblock. The painstaking manner in which many of these cords or thongs are secured to the boards indicate that their use as a means of board attachment was considered 28
significant. Their effect on the sewing or leaf attachment was incidental to this quest. Furthermore, the addition of raised cords and thongs may have strengthened the textblock but only at the high cost of adding tremendous stress to the sewing when the book was actually opened (see Flexible Strength). So, what is the significance of all this? It is that a book's cover or case is secured via the spine and not the endsheets. Books designed and repaired on this principal have a good chance of success. Books built on the premise that endsheets provide a structural role essentially transfer the stress of board attachment from the spine, a very secure base, to whichever page follows the reinforced endsheets, a very weak link. If the endsheets have cloth reinforced hinges and are sewn on as signatures at the beginning and end of the textblock, this may pull the inter-signature sewing into play as a support for the cover. This may not be desirable as it can add stress to the sewing that is better taken on by the super. However, if the book's spine is properly reinforced with a strong super the inter-signature sewing is no longer structurally in play and the reinforcement of the endsheets becomes superficial. And as an afterthought, what makes a good super? How well a super does its job depends on its strength and how well it adheres to the spine and the boards. The super should be supple enough when wet with adhesive to conform to minor irregularities in the the spine. It should breathe sufficiently that air can pass through it, preventing air bubbles from forming underneath, and it should not delaminate when subjected to the normal motion of a book's spine. Good adhesion depends on two factors, the adhesibility of the mating materials and the actual surface area available for adhesion. Given any two materials the greater the surface area being glued the more difficult they will be to separate. Given these criteria we can evaluate different materials. Paper lacks tear strength, is not breathable, does not conform to irregularities in the spine and delaminates with the normal flexing of the spine. Tyvek has tear strength but shares all of paper's other shortcomings. Gauze or cheesecloth supers come in many different flavors ranging 29
from from very weak to very strong. Their use in glue is frequently compared to steel reinforced concrete. I consider this analogy invalid and misleading as the properties of a flexible bookbinding glue are in no way analogous to concrete nor are the structural expectations of a spine in anyway similar to that of reinforced concrete. Whether weak or strong, all cheesecloth type materials offer less surface area for adhesion than cloths more fully woven. This absence of surface area is most telling not on the spine but where board meets cloth. Cheesecloth supers tend to readily delaminate not from a book's spine but from the hinge and board areas. Some cheesecloth supers also appear to be made of synthetic materials that do not adhere well. A strong, tightly woven (but not so tight it lacks breathability) non-synthetic cloth makes the best super. My personal preference is a cotton cloth with a 68 x 68 thread count cloth sold by Library Binding Service (www.lbsbind.com). There are probably similar cloths sold elsewhere - this is simply the company I dealt with. If the spine is going to be reshaped after glue-up, which is the case with fan-glued bindings that will be rounded, the super must be capable of stretching. This requires a cloth specially designed to do so. The super I normally use will split if subjected to rounding. LBS, as well as other bindery supply houses sell stretch lining materials similar to the cotton backlining. However, unless a particular binding requires a stretch cloth there is no reason to use one.
Reflections on Book Structures - part 2 by Pete Jermann
In June of 1998 I gave a presentation on fan-glued binding and adhesive book structures to the Library Binding Discussion Group at the annual ALA conference. What follows is a partial writing of ideas that have existed only in outline and illustration since that time (a more complete writing will continue in part 3 of these "reflections"). My reflections herein are based on observations derived from my experience with fan-glued bindings. Most of my observations are derived from experience, a magnified examination where possible using a dissecting microscope, and by page pull tests using a tester of my own devising. Not being an adhesive engineer, the terminology herein is pretty much my own. Any feedback from my reading public is appreciated.
Thoughts on PVA PVA is the core component in a family of glues all of which tend to be non-discriminately referred to as "PVA glue." Like the term "perfect binding" the unqualified use of the term PVA can easily mislead. The core ingredient of PVA, polyvinyl acetate, is simply the starting point for many different glue formulations. PVA in its purest state dries hard and brittle and is absolutely unsuitable for bookbinding purposes. PVA is blended with varying materials to add flexibility and other properties. "PVA glue" in binding circles has probably become shorthand for a flexible PVA. Flexibility, however, is a very flexible term. A sheet of paper is flexible as is a rubber band but one is elastic and the other isn't. Blended PVAs can exhibit a similar range of the characteristics from fairly hard, yet flexible like a sheet paper, to very soft and very elastic like a rubber band. Understanding a PVA bond requires that we distinguish between its adhesive strength and its cohesive strength. Its adhesive strength is the force with which it attaches itself to a substrate, such as paper, board or cloth. In bookbinding for a glue to be successful it must 31
adhere to both the paper substrate and any liners used to reinforce the spine. Ideally the strength of adhesion should be greater than any stress that is exerted on the joint between glue and substrate. If this is so then a glue is sufficiently adhesive. However, PVAs do more than adhere two substrates to each other. PVA forms a film between the substrates. This film has its own characteristics. If the film itself fails, the joint will fail. The internal strength of the film is its cohesive strength. The greater the cohesive strength the greater the force required to separate the film. Though I am not an adhesive scientist, my observations indicate an inverse relationship between cohesive strength of a PVA and its elasticity: the more elastic a PVA the lower its cohesive strength. The distinction between highly cohesive and highly elastic PVA can be described tactilely as PVAs that form a hard film (high cohesive strength) and PVAs that form a soft film (high elasticity). These distinctions appear to be moot when gluing paper or cloth to board (but on close examination, they may not) but they may be quite significant when glue is used on the spine of a book or the joint area where the PVA assumes a structural role beyond simply that of sticking two materials together. I have found that most PVAs I have worked offer sufficient adhesion for binding purposes. It is their cohesive/elastic properties that tend to be most significant.
Reflections on the Glue Line Pull and Peel Books are comprised of glue, paper and cloth. All of these are flexible materials. Once glued together they are subject to various stresses when a book is used. Basically there two types of stress on a glue joint which I unscientifically distinguish as pull and peel. The various laminate structures formed throughout our bound book are subject to either one or a combination of both of these stresses when the book is use or even when the books sits upright on a shelf. Understanding which stress comes into play and how contributes to proper book design. 32
Pull is stress applied evenly across the entirety of the glue joint and parallel to the glue joint. Peel is stress applied to and concentrated on the edge of the glue line. (see illustration to the right). Peel represents the stress we would normally associate with removing a piece of pressure sensitive tape from a surface. We start at one end and we lift and pull back toward the other end exerting stress at the joint between the tape already lifted and the tape still attached. This approach to tape removal divides and conquers the tape's resistance to removal. If we pull the tape parallel to the glue line the stress distributes across the entire glued joint. Such would be the case if we apply a length of our pressure sensitive tape to a tabletop with a tab hanging off the edge. If we pulled this extended tab parallel to the desktop (as shown in the illustration) the tape will be almost impossible to remove. Chances are that the tape itself will break before the glue line fails. A pull stress maximizes the effectiveness of a glue joint while peel stress minimizes it. Wherever possible we should design to a glue joint's pulling strength rather than its weaker peeling strength. This, however, is not always easy to do. Sometimes we simply have to deal with a peeling stress. The joint area between the board and the spine is frequently subject to a peeling stress as is the super to textblock. We will also see that the page to page joint in a fan-glued binding can be subject to either peel or pull stress.
The easy answer to strengthening these areas is that a stronger, more cohesive glue will give us the strongest joint. The greater the cohesive strength of the glue the greater the strength of the joint. However, the divide and conquer nature of a peel stress actually inverts this assumption. Assuming good adhesion, a highly cohesive glue tends to concentrate a peel stress whereas a less cohesive, more elastic glue, tends to distribute that stress. (see illustration to the right). By distributing stress the "weaker" less cohesive, more elastic, glue is actually more resistive to a peeling stress than a stronger, more cohesive glue. Furthermore, a highly cohesive glue places greater local stress on the substrates themselves frequently contributing to their de-lamination. Within the last ten years or so an adhesive demonstrating this principle has emerged as a way to attach loose advertising items or cards into popular magazines. At one time many of these items were tipped in with a standard, non-elastic glue. The item usually could not be easily peeled out, without either delaminating part of itself or the page to which it was attached. These new adhesives are sufficiently elastic that the stress is distributed widely. Pulling these cards out is a task that sometimes endangers the attachment of the page to which it is connected. If you work at it carefully, however, you can actually remove the card and remove the glue without damaging either, indicating that not only are its cohesive properties low but so are its adhesive properties. But its elastic properties are impressive. The removed glue can be rolled, reformed, stretched to 34
your heart's content and then pressed to another object to be used again. I must admit to having neither a name nor any further information as to what exactly this adhesive is but I do think it demonstrates well the contribution of elasticity to an adhesive. Summarizing briefly, elasticity in a glue distributes stress in a peeling situation where stress tends to be concentrated in a small area. Should stress already be distributed, as in a pulling situation, an elastic glue would provide a bond that is weaker than a stiffer, more cohesive glue.
Page Attachment and Adhesive Elasticity Assuming sufficient adhesion, a PVA with high cohesive strength does not necessarily make for better page attachment. In the dynamic environment where a page meets the glue line elasticity can offer advantages not suggested by simple page pull strength. The diagram
A Note on Drape Factor: Anybody who reads books has experienced what I refer to as the drape quality of various papers. Some papers simply flop right over when a book is opened. Other papers prefer to stand straight up and many others fall some where in between. I have quantified this particular characteristic with what I call the drape factor and a simple tool I call a drape gauge. I define the drape factor as the distance in tenths of an inch a given sheet of paper can be extended beyond a horizontal edge (think table top) before the lead edge drops 1 inch. For instance, a typical page from a National Geographic Magazine extends 3.4 inches before dropping 1 inch. It has a drape factor of 34. Time magazine pages tend to have a drape factor of about 24. A ten point card stock has a drape factor of 44 with the grain and 56 perpendicular to the grain. The higher the drape factor the the stiffer the paper and the more potential energy there is when the page flexes at the glue line. Drape factor is measured with a single detached page. Some cross grain papers will cockle at the gutter edge when glued. If this cockling remains after the glue dries, it effectively increases the drape factor of the page.
to the right shows the joint where two different types of paper meet two different glues. The papers are differentiated as low drape, papers that tend to bend easily or drape well, and high drape, papers that are stiff and do not drape well. A low drape paper tends to work well with either a stiff, cohesive glue or an elastic glue as the paper itself gives and, consequently, generates low potential energy at the glue line when flexed. Little is required of the glue itself. Stiffer papers, however, presents another problem. If the paper is allowed to flex at the glue line, it will concentrate significant potential energy there. This will ultimately resolve as a peeling force on the glue line and the joint will fail as shown in the illustration above. An elastic glue, however, will both compress and stretch allowing the page to flex without failure. Though elasticity allows movement, it does have less pull strength than a stiff, more cohesive glue. The key concept is movement. If the spine opens fully, the glue line is exposed to higher potential energy than if the spine is controlled in a way that the pages are not 36
free to flex at the glue line. In the former case an elastic glue is called for and in the latter case a stiffer glue. This will not always be a clear choice but will be the best compromise between what the binder would like and what he can actually achieve.
Glue Joint Failures Understanding how something fails is basic to devising a working solution. The success of a fan-glued binding depends largely on the success of the bond between the pages. This bond can suffer either failure of the glue or failure of the substrate. (see illustration to the right). Glue failure assumes two forms. The glue suffers adhesive failure if the bond between the glue and the substrate fails. The glue suffers cohesive failure if the glue film separates. Substrate failure also assumes two forms. The substrate suffers surface failure if the adhesion of the glue is adequate but a part of the substrate or paper detaches under stress. The substrate suffers internal failure if the glue adheres but the substrate fractures or splits under stress. Substrate failure is more likely than glue failure and the way the substrate fails tends to be quite different coated and uncoated papers.
Coated Paper and Uncoated papers Uncoated papers tend to exhibit internal failure, splitting internally when stressed. However, this turns out to be a distinct asset rather than a failure. When a book opens basic physics determine that something has to give way at the point of opening. My earlier supposition (which I stated in "Flexible Strength") was that the glue, if sufficiently elastic, provided the necessary give. My observations since then have shown that it is not the glue that gives but the paper itself. The splitting of the paper allows the book to open fully while accommodating itself to the inevitable expansion at the apex of the opening. Even though the paper splits internally the page pull strength remains high. Fan-glued books comprised of uncoated paper are very durable providing they are built with a proper adhesive and supporting structure. While uncoated papers exhibit internal failure under stress, coated papers tend to fail at their surface. Though the high failure rate of adhesive, coated paper bindings is often attributed to poor adhesion, it is more often the case that glue sufficiently adheres to the substrate. It is the attachment of the coating to the paper that fails. A close examination of detached pages will usually show the coating delaminated from the edge of the page and still attached to the glue in the margin. Stiff papers that present the glue line with a large amount of potential energy can also act much like coated papers and have been grouped with them in the following examples. 38
How a substrate surface failure (or adhesive failure) resolves in a fan-glued book is shown in the illustration to the right. With an elastic glue the bonds between the opened pages fail, leaving the exposed sheets secured only at their edge. Furthermore, due to the elastic nature of the glue the adjoining pages slip and slide (no doubt aided by the low friction between coated pages) and the bonds between the adjoining pages tend to fail periodically, skipping a page or more, creating stepped blocks of pages. The leaves remain attached but resistance to forces pulling on the page is very low. Such a book will not do well under heavy use. Should a stiff glue be used, failure is more immediate. As the glue has little elasticity, the pages at the opening tend to detach. The bonds between adjoining pages tend to shift and break in a fashion more consistent than with an elastic glue. These books perform terribly on a page pull test. The page will frequently pull loose in the process of trying to set up the pull test. Searching for a glue with better adhesion will not solve the problem as most glues adhere adequately to the coating. Should adhesion to the coating be the problem its solution will simply transfer the point of failure to the bond between the coating and the paper. One approach to solving this problem is to remove the coating where 39
the glue is to be applied. Sanding the edge of the pages prior to fan-gluing is one way to do this. My own page pull tests, however, have indicated that hand sanding prior to fan-gluing has no discernable effect and is merely a waste of time. The sanding action would need to remove the coating from the edge of the page without removing too much of the page. This is probably almost impossible to do manually. Sanding after milling the edges in a mechanized environment may be more effective if each page is momentarily separated out by a fanning action across a sanding drum. Not having access to such equipment I cannot comment one way or the other on its effectiveness. I believe the solution to the coated paper problem, at least in a hand bindery, lies elsewhere.
Spine Movement and Leaf Attachment The solution to successfully fan-gluing coated papers lies in controlling the spine. The failures cited above are based on a book that opens flat. When a book opens fully as pictured above, the adhesive bond between the pages is subjected to peeling forces. The stiffer the paper the greater the peeling forces. Books using uncoated papers can be designed to work very well with a flat opening, but a relatively elastic glue should be used. An elastic glue will increase adhesion between the pages by better distributing the peeling force and will provide for the increased 40
movement required by the spine at the point of opening. Because of the likelihood of adhesion failures due to the weak bond between coating and paper, coated papers must be treated differently. Rather than design our leaf attachment to resist potentially destructive peeling stress, we design to avoid peeling stress altogether. Ideally, we want any stress on our leaf attachment to be a pulling force. This will ensure that the entire glue/paper joint comes into play and will significantly decrease the chance of a page detaching. We can do this by controlling the motion of the spine. The illustration to the right shows an example of a spine that is locked into a flat position with a stiffening element (in my actual experimental sample I glued a piece of binders board to the spine). A spine so stiffened will not move or "vee" up to the glue line. The pages remain locked into a vertical position at the glue line preventing an opening that exerts peel forces on the page to page junction. Whereas we maximize our strength against peeling with an elastic glue, we maximize our strength against pulling with a stiff, strongly cohesive glue. When samples distinguishing between a freely moving spine and a stiff spine are subjected to a page pull test the difference is dramatic and varies with the strength/elasticity of the glue. My own page pull tests indicated the more elastic the glue the less the impact of stiffening the spine. I tested books comprised of pages from National Geographic Magazines and compared the page pull strength on samples using five different glues. For each glue I made two samples, one with a single super that allowed the sample to open flat to the glue line and one with a super, a strip of binder's board and a second super to further secure the binder's board to the spine. The reinforcement on the second sample immobilized the spine. The difference in pull strength from movable to immovable was at least double for the more elastic glue and up to seven times stronger for an inelastic glue. To push my experiment to the limits I used a yellow wood glue (probably PVA but without any plasticizers added). This glue dries stiff and brittle. The two samples glued with the wood glue illustrated the limits of pull and peel. They were both the strongest and the weakest in the page pull tests. The pages in the 41
sample with the free moving spine hardly survived the opening of the book. They had the lowest pull strength of any glue tested. The wood glue's resistance to peel stress was almost nonexistent. However, the pages in the sample with the immobile spine had the highest pull strength of any glues tested and seven times the pull strength of its freely opening counterpart. This is not to suggest that spine control be absolute as in my test samples. The degree of control required actually tends to correlate with the drape factor of the paper. The lower the drape factor (paper that drapes well) the less the binder needs to control the spine. A low drape factor paper, such as the typical Time magazine, only needs enough control to keep the spine from opening fully to an inverted "vee" opening. Control that allows a small radius at the point of opening is probably sufficient. As the drape factor increases the radius at the point of opening should increase. Unfortunately, this also means that stiff papers require the most control and, consequently, they produce the least openable or user-friendly books. This can be ameliorated by providing for a generous gutter margin. I should also note that I did tests with uncoated paper with controlled and uncontrolled spines. With a properly elastic glue, the difference in pull tests was negligible. If a proper glue is used there is no advantage (at least in regard to leaf attachment) to adding anything beyond minimal control (usually provided by a single layer of super) to the spine. I would also reiterate that stiff papers, whether coated or uncoated, tend to behave similarly to flexible coated papers in the way they fail and often need to be treated is a similar way. My conclusion: The adhesive attachment of a single leaf cannot be viewed in isolation from the structure to which it is attached. A structure can play to either the strengths or weaknesses of a given glue. The pages, the glue, the spine linings and the case all work together as a coherent structure regulating the action of the spine and creating the dynamic environment that ultimately affects leaf attachment. Many of us have experienced firsthand the role of structure in leaf attachment. Think of a paperback book with a thick, stiff to brittle , heavy layer of hotmelt adhesive on the spine. 42
The hotmelt immobilizes the spine. The book may be difficult to read but the pages remain intact until the spine gives. Once the spine breaks, the pages will often come loose either individually or in blocks. Designing durable books requires understanding how all the components work together. The single most important decision in designing a durable book structure begins with choosing the paper that makes up the individual pages. Most every structural decision that follows is based on this first decision. Unfortunately, the binder is seldom involved in selecting the paper and must compromise to find the best solution for the raw material with which he is presented.
Reflections on Book Structures - Part 3
by Pete Jermann
Spine Control In Reflections on Book Structures -Part 2 I discussed glue line failures. This article looks at the physics of the spine and the means by which it is controlled, whether intentional or unintentional. Understanding the physics of the spine and its effect on the glueline or point of leaf attachment contributes to better book design. The need for and the amount of control required is predicated on the understanding of glue line failures and the concepts of “pull” and “peel’” stresses discussed in part 2. Though my focus is on fan-glued bindings, the principles and methods discussed lead to a better understanding any kind of binding, whether it be sewed or glued. A good story frequently begins with a good picture. When I wrote the section in part 2 on “Reflections on the Glueline” I illustrated with diagrams what I could see through the microscope. With the cooperation of a biology professor at the local university, I recently secured the use of a digital microscope and took pictures of the glueline in two sample books, one comprised of uncoated paper and the other comprised of coated paper. These pictures both confirm and add to the diagrams I presented in Reflections- Part 2. Both pictures were taken on textblocks lined with a single liner and glued with a very elastic glue (colored with green food coloring to make it more visible) The textblock opened fully flat such that the spine folded back on itself. The need for spine control, when we need it and how much we need grows from an understanding of what these two pictures show. To quickly review the discussion in Reflections on Book Structures - Part 2, the glue bond between uncoated papers remains intact as the leaves split internally and expand to the arc required by the opened book. As some give is always required at the point of opening, 45
this break-in is ideal and does not affect the durability of the book. However, the bond between adjacent leaves of coated paper fail where the coating and paper meet. The glue is not the problem. The paper is the problem. When a book opens fully the joint between the pages is subject to peeling forces. Whereas glues with adequate adhesion and elasticity are readily available, the inelastic adhesion between the coating and the paper easily peels apart. This negates and overrides any advantages the glue may offer. This is a case where we want to design to the stronger pull strength, rather than the weaker peel strength, of the adhesive bond between the coating and the page. By controlling the motion of the spine, we prevent the peeling forces from coming into play. This strengthens our page attachment allowing it to better resist pulling forces the leaves may be subjected to when the book is used. An article on â&#x20AC;&#x153;spine controlâ&#x20AC;? should begin with a definition. Spine control is the ability to determine how much the spine flexes when a book opens. Frequently, as with many commercial hotmelt bindings, the process, rather than the needs of the particular book, determines the amount of control. In many cases the result is a fixed spine, one that does not flex at all. Most of these books fail the reading-whileeating-lunch as holdingradius the book open requires the same hands Flat test opening/small you need to eat your lunch. While a fixed spine is the easiest path to a durable book, it is also the least user friendly unless it is blessed with large margins and a paper that drapes very well. Many books would benefit from a flexible, more user-friendly spine. Let me start by establishing a terminology to describe three degrees Controlled opening/largeradius of spine control. When we open a book the spine flexes into an arc, either along its entire width, along a finite part of its width or not at all. The spine of a book that opens flat to the middle will take the shape of a hairpin with the opening at the head of the hairpin. The radius of the opening is quite small and barely perceptible. However, Fixed spine/no under magnification it is radius evident that no matter how tightly the spine turns back on itself there is a small arc at its apex. This flat-opening book with an arc of an often imperceptible radius represents our first Typesofofspine Spine Openings category control. At this level there is essentially no control. 46
A Microscopic View of a Fanned Glueline
The bond between the opening pages has broken, and the glue line has spread to expand to the arc required by the tight radius.
End view of the threads in the super (68 x 68 thread count). The weave of the super is loaded with the pva, integrating it into the glue layer.
Notice the elasticity of the glue (colored green with a bit of food coloring to make it more visible) which moves and forms with the pages when the book opens. The glue is visibly a dynamic, unique layer with its own characteristics rather than simply an invisible bond between the leaves and materials making up the spine.
The bond between the pages remains intact.
To accommodate the expansion required by the tight opening radius, the pages split, allowing the glue line to expand to the required arc.
Our binding structure is designed to not impede movement of the spine in any way. This creates the most user-friendly book and represents an ideal most binders would probably like to achieve. However, achieving a durable, flat opening with an adhesive binding requires excellent adhesion with an elastic glue, a condition that is hard to achieve with some papers, particulary coated papers. The second level of control I have chosen to call a controlled opening. In these books the motion of the spine is controlled such that it flexes into a fairly even arc across the spine. The radius of the arc may vary, but there is enough structure, by design or happenstance, to prevent a flat opening. The third level of control is the fixed spine . As a flat-opening spine essentially represents no control, a fixed spine, conversely, locks the spine flat and prevents any movement at all. So, why do we need to control the spine and at what level? A fixed spine produces a durable but, frequently, lousy book as the reader must dedicate himself to holding the book open and can only despair should the need arise for a decent copy or scan. Forcing a book with a fixed spine into a more compliant attitude tends to actually damage the book such that the spine actually breaks or assumes an attitude that now prevents it from closing properly. However, for very thin books, providing they have an adequate gutter margin and a paper that drapes well, a fixed spine is often the best solution. On the other end of the spectrum, the flat-opening book answers well to useability and can be durably constructed with many uncoated papers. However, there are instances where a flatopening binding simply cannot be durably constructed with either the materials the book demands or the materials presented to the binder. Usually these are coated papers, but they may also simply be papers that drape poorly. In between the fixed spine and the flat opening spine, the controlled spine is an attempt to find the best compromise between durability and useability. The amount of control varies with the paper and the thickness of the book. The goal is to add control sufficient to prevent the failure of the bond between the pages. 48
At the beginning... When we start with a loose stack of the pages that will comprise a book, we start with total freedom of motion. The pages can be opened flat or separated at will. As soon as we consolidate the pages into a textblock this freedom of motion changes. From here on out every step in the binding process from adding glue to lining the spine to building the case has the potential to further limit that freedom. The key to achieving the required amount of control is in understanding what you want to achieve and how each step affects that goal. Two major structures affect the motion of spine; the construction of the textblock’s spine and the construction of the cover or case. I will address the spine’s structure first. The finished spine of a textblock is a laminate, a layering of various materials, beginning with the book leaves themselves and building out with glue and various liners. Let me start with the paper that makes up a book’s leaves.
Paper A book begins with paper. It is paper that makes up the pages that give the book its purpose. Books are printed for many different reasons and for many different intended effects which, in turn, leads to many different papers with many different characteristics. It is the paper which determines the binder’s possibilities. With a proper binding structure most any paper can be successfully bound into a useful and durable book. With the wrong binding structure most any paper can produce a book bound Drape Gauge to fail. The paper making 49
a book’s pages is the most important component of the spine. The paper sets the criteria for a book’s structure. Paper has three defining characteristics which contribute to and affect the development of the spine structure, its 1) drapeability (my own term) 2) its adhesibility and _) its cohesivesness or how it gives internally under stress. Drapeability refers to a paper’s ability to naturally fall or drape into the gutter margin of an opened book as opposed to leveraging away from the margin. Very loose, floppy or drapeable papers easily flex into the margin. These papers tend to produce books that “flop” open easily regardless of binding, whether it be sewn through the fold, sidesewn or adhesive bound. Less drapeable, stiff papers tend to remain noticeably erect when a book is open or require noticeable force to fully open a book to a readable position. Drapeability is an indicator of how much leverage a paper is capable of exerting at the glue line. A paper’s drapeability can be measured on a relative scale. I constructed a fairly simple device (see illustration below) that measures what I refer to as the drape factor. The drape factor is determined by the number of inches a paper extends from an edge until it drops one inch at the leading edge. The measurement itself I express in tenths of and inch. Hence if a paper extends 3.2 inches before it drops one inch it has a drape factor of 32. For purposes of comparison a typical page of a current National Geographic has a drape factor of 34, a page in Time Magazine a drape factor of 24, and a piece of 10 pt bristol (paralell to grain) a drape factor of 57 and (crossgrain) a drape factor of 72. These drape factors represent single unglued sheets of paper. Any edge cockling significantly increases the actual drape factor of any paper at the glue line. Drape factor gives us a relative means of comparing the potential energy different papers can exert on the glue line. The higher the drape factor the greater the potential energy if the pages of a book are constrained when opened. This energy is potentially destructive. The binder can either counteract it by by controlling the spine or dissipate it by letting the pages move freely into a flat opening. A high drape factor (stiff) paper challenges the binder. He or she can design a book that either resists the built up potential energy or 50
dissipates the energy. Should the binder choose the path of resistance, he/she must make sure the resistance is sufficient otherwise the binding will self destruct. The higher the drape factor the greater the amount of control required. Should the binder choose to dissipate the energy rather than control it he/she must ensure that in doing so the durability of the binding is not unnecessarily compromised. The path the binder takes is dependent both on what the binder expects of the finished product and other characteristics in the paper that may force him or her to compromise between what is desired and what is achievable. The other characteristics of a paper that affects its bindabiliy are its adhesibility (its ability to successfully bond with an adhesive) and itâ&#x20AC;&#x2122;s internal or cohesive strength (ultimately defined by how it gives into stress). As discussed previously, uncoated papers tend to split internally, whereas coated papers tend to give between the coating and the paper substrate (the paper lacks cohesive strength). If the substrate is highly cohesive then failures may be solved by increasing the adhesibility of the glue. However, if the paper substrate fails, as is frequently the case with coated papers, a more adhesible glue will not solve the problem. In summary, when we begin building our book we are confronted with three questions. Does the paper drape well? Will our adhesive bond well with the paper? And, will the paper itself remain intact when subjected to the open- ing stresses of a book? Before looking at the structures that might answer the combinations of answers we receive from the above questions, we need to understand the other components of the book, beginning with glue.
Glue Glue can be made of many different substances for many different reasons and to achieve many different effects. Understanding glue requires seeing it as more than a simple bonding material but as a unique layer in the structure of the spine. Just as we would consider that a piece of paper lining the spine would act differently than a piece of cloth or vellum we need to understand that different glues 51
will have different effects. These structural effects tend to be within the film the glue forms rather than in the actual bond with the substrate. Assuming adhesion is sufficient, which is the case with most glues used in bookbinding, the qualities of glue that affect our book structure are flexibility, elasticity and thickness. For a glue to be useful as an adhesive on a bookâ&#x20AC;&#x2122;s spine, it must be flexible so it can move with the spine when the book opens. If it is not flexible the glue will crack. Many of us have seen old paperbacks that literally crack when opened. My guess is that these books were not intentionally made this way but were functioning books made with a flexible glue that became brittle with time. Without flexibility a book will break in use. Elasticity is the ability of the glue to stretch and return to a previous state like a rubber band. Whereas a piece of paper is flexible we would not characterize it as elastic. Most glues we use in bookbinding are flexible, but many are not very elastic. I will refer to glues that are flexible, but not so elastic, as stiff glues and the more elastic ones as elastic glues. The ability to build thickness is the third characteristic that affects its ability to control the spine. Some glues have more solids and build thicker films. Hotmelt glues that depend on heat and cooling to apply rather than the evaporation of a solvent can easily build to a substantial thickness. So how do these characteristics make a difference? A stiff glue will tend to control the movement of the spine more than an elastic glue (see illustration above). For any given glue, the thicker the glue film the more it will control the spine. If you are designing a book to open flat with a minimal radius at the point of opening you need a glue that is elastic. On a microscopic level there is significant dimensional change at the point of such an opening. A stiff glue simply cannot accommodate the dimensional change. Viewed under a microscope an elastic glue visibly gives (think of a wad of gum on the bottom of your shoe pulling away from the pavement). As long as the elastic limit is not exceeded the glue returns to it initial shape. 52
This cycle can be repeated indefinitely if the glue is sufficiently elastic. If it isnâ&#x20AC;&#x2122;t it will fracture and fail either immediately or over multiple uses. So why choose a stiff glue over an elastic glue? Because basic physics requires a compromise. We canâ&#x20AC;&#x2122;t have both elasticity and brute strength. An elastic glue must give in order to stretch. At some point it will stretch to the point of failure. Its cohesive strength is lower than that of a stiffer glue. In page pull tests elastic glues yield before stiffer glues. A stiff glue has stronger cohesive strength, resists stretching and requires a greater force to produce failure. The binder must decide between the need to give and the need for more strength. Generally speaking, a binding that opens flat requires the give of an elastic glue. If our book is to be more controlled a stiff glue will both strengthen and add control to the spine. In addition to the elasticity and flexibility of the glue the thickness, or depth, of the film affects the movement of a bookâ&#x20AC;&#x2122;s spine. With cold emulsion adhesives, such as the PVAs frequently used on bookbinding, the binder seldom uses thickness to control the spine. These adhesives dry relatively slowly and require many layers and much time to build up a controlling thickness. Such is not the case 53
Take any flat item
Top dimension = Bottom dimension
B. Bend it slightly (large radius)
COMPRESSION Top dimension slightly excedes bottom dimension Center line = Original dimension
C. Bend it some more (small radius)
Top dimension greatly excedes bottom dimension Center line = Original dimension
with hotmelt adhesives where thick layers can be quickly applied as cooling is all that is required for the glue to cure. Whereas books bound using PVAs require futher measures to ensure control of the spine, books bound with hotmelts can achieve control simply by controlling the thickness of the glue. This is evident in many paperback books bound with stiff hotmelt adhesives. You can remove the covers from many of these books and the spine will remain stiff. This is a function of both the fact that these glues are generally stiff and because, compared to a PVA emulsion, they are quite thick. They resist the movement of the spine without the additional measures (liners, case control, cords, etc.) that a PVA binding may require. Once we move beyond paper and glue, the binder will frequently use any combination of materials such as cloth liners,
Dynamics of the Bend Cloth tears at point of expansion
Board and cloth buckle at point of compression
Binderâ&#x20AC;&#x2122;s board breaks at point of expansion
The approximate location of the pivot line, the middle layer is largely undamaged
Binderâ&#x20AC;&#x2122;s board buckles at point of compression
Elastic and Compressibile
BB = Original dimension Outer surface expands. Inner surface compresses.
paper liners, cords, tapes, synthetic materials like tyvek and even binderâ&#x20AC;&#x2122;s board. What these materials do begins with an understanding of the pivot line.
The Built-up Spine and the Pivot Line
A bookâ&#x20AC;&#x2122;s spine is a three dimensional object comprised of not only the two obvious dimensions, the length and breadth of the spine, but most importantly the thick- ness. C C As soon as we add glue to the spine we add thickness, even if it is only a thin film. When we fan-glue we AA = Original dimension Outer surface remains constant Inner surface compresses. also must add to the accumulated thickness the depth of the glue beElastic and Incompressibile twe e n t h e A A C C pages. A suCC = Original dimension per Inner surface remains constant adds Outer surface expands. more A. Spine controlled thickfrom center or ness and any additional layers, cords outer edge or tapes continue the buildup. In order to understand how best to control the spine, we need to understand the basic physics of a three dimensional object when it bends or flexes. As a object bends the convex side expands and the B. Spine controlled Inelastic and Compressibile
from inner edge
concave side compresses. (See illustration on page 54)
Sewing and pivot lines - the two samples above show the effects of sewing on the pivot line. The sample sewn with a chain stitch has a pivot line relatively close to the line of stitching. The sample sewn on cords (actually, clothesline) has a pivot line well removed from the stitching causing a signifi- cant spread at the line of stitching when the book is opened flat. This textblock will require signifcant spine control to prevent if from opening flat and pulling the signatures apart
Everything toward the convex side of the line expands and, conversely, everything to the concave side compresses. Whereas everything can work in the theoretical world, the real world is quite different. The illustration to the 56
The diagram on the next page assumes a homogeneous material that expands as well as it compresses. In this theoretical case the pivot line is represented by the red line in the middle, between the lines of maxi- mum expansion and maximum compression. The pivot line is the line between the expansion and compression line where the original dimension of the object, before it was flexed, remains unchanged. Moving the Pivot Line
Pivot line in the middle A paper and binderâ&#x20AC;&#x2122;s board laminate breaks when bent.
Pivot line on the outside - The addition of a 5 mil piece of mylar J (a glueable mylar) between the paper and the board, moves the pivot line from the center of the board to the inelastic mylar. The entire board side of the bend is now in compression (and buck- ling). Expansion on the paper side is severely restricted and the paper remains intact.
right is a laminate of three pieces of thin binder’s board with a cotton super on the top side. I did two hairpin bends on the sample in different directions to show the effects of bending a three dimensional object. The sample was purposely designed to exaggerate the results in a very visible way. Where the sample was bent such that the cloth super expanded, the cloth actually pulled apart. It did not require significant effort on my part to do this as the bending of the sample significantly leveraged my minimal effort at the point of expansion where the cloth broke. If you took a similar sample of cloth and tried to break it in the middle by evenly pulling at the two ends you would find this extremely difficult. A quick look at the reverse bend shows that the outer board broke. The forces of expansion are significant. The maQuarter-joint Math terial expanding must be sufficiently Start with a elastic or giving to accommodate the book 2” required expansion or it will break. thick with Before we leave our sample, we also need to look at the concave or compression side of the bends. In this case the compressive abilities of the board were exceeded and it buckled. The board actually delaminates and bulges out to accommodate the re-
1/2” joints (1/4 the thickness of the book)
duced dimension required by the compression. As is the tearing on the expansion side, this damage is not As it opens the two corners of the textblock move reversible and the area of the bend toward each. The joint areas move freely away from the textblock as the boards move with the remains permanently weakened. We textblock. frequently see such damage in books ½” with paper liners or in paperbound ½ ” books where the natural flexing of the opening book has created lines of The distance between the corners of the spine is zero. The corner of the spine has moved in ½ delamination at various points of open- now ” relative to the edge of the case spine. The case ing. As the materials should be care- spine has moved out ½” relative to the textblock spine for a total of 1” of movement one side and fully considered for the expansion side 2” of movement for both sides. 57
of the bend so should our materials be considered for the compression side of the bend. Finally, note in the sample that the largely intact middle board forms the pivot line. Once we understand the concept of the pivot line, we also need to understand that it is not necessarily in a fixed position relative to the opposing expanding and contracting areas. The following diagram (on page 55) shows three theoretical maTop: Sample textblock with beads of hotmelt terials and how they might afglue added using a standard glue gun. Bottom: fect the pivot line. The first The same sample opened. Inset: A pair of pliers sample represents our original show the compressibility of a standard stick of hotmelt glue. When released the glue will slowly theoretical sample and also our return to its original shape. bent board sample where the pivot line is located approximately in the middle (represented by the red line). The second sample is a theoretically inelastic but compressible material. In this case there is no expansion because the material simply will not expand (yet has the strength to resist breaking) but it will compress. In this case the pivot line falls on the outermost side of the bend. With the third sample we have the reverse, where our material is very elastic, but incapable of compressing. In this case the pivot line falls to the very inside of the bend. While fully inelastic/compressible and fully elastic/incompressible materials are probably not actually available to the binder in a useful form, we can mix and match our materials to shift the pivot line favorably. Why is the location of the pivot line important? The following diagram shows a spine structure with two possibilities. In the first the pivot line is in the middle or toward the compressive side of the spine structure and in the second the pivot line is at the point of leaf 58
attachment. Given the first possibility the point of leaf attachment must accommodate a much greater level of expansion than the second possibility where the pivot line and the point of leaf attachment coincide. Ideally, as bookbinders, we want to achieve the second possibility which greatly reduces stress at the point of leaf attachment. This is especially true with fan- glued books but also true with sewn books where undue stress at the point of opening can Notching cause the signatures to separate (see illustration on page 56). We vary the location of the pivot line in a bookâ&#x20AC;&#x2122;s spine through the materials we use. The illustration (Moving the Pivot Line - page 16) shows two almost similar structures performing quite differently. I laminated two pieces of binderâ&#x20AC;&#x2122;s board; one with a piece of paper and a second with a piece of Mylar J between the paper and the board. When the first sample (without the mylar) was bent the paper broke. The pivot line in this sample is approximately in the middle of the board. Expansion begins in the middle of the board and moves out. The expansion at the apex of the bend was more than the paper could handle, and it broke. The addition of the mylar radically changes the pivot line. The mylar is the strongest and most inelastic material in the laminate. Because of this it becomes the pivot line even though the board comprises about 90% of the thickness of the laminated piece. When bent the board goes entirely into compression limiting the expansion on the paper side of the mylar to a now tolerable level. Once we begin to build up the spine by thickening the glue or adding various liners, cords or other structural variations it is important to understand where we want our spine to give and where we donâ&#x20AC;&#x2122;t. Materials on the convex side should be elastic or giving (as 59
uncoated papers do by splitting). The elasticity or amount of give depends on the movement required. The smaller the radius of the opening arc the greater the elasticity and give required. Materials on the concave side should be compressive. If we are using spine structure alone to control the spine, the more material we add to the concave side the more controlled our spine will be. Ideally the pivot line should be as close to the glueline or point of page attachment as possible. With books having a large opening radius, placing the pivot line is less critical, as the difference between the line of maximum expansion and maximum compression is relatively small. However the smaller the radius the greater the difference in these two values
The effects of different linings on spine control - The samples above are all glued with the same PVA but lined differently.
and the more critical it becomes that the pivot line is as close as possible to the point of page attachment. Without encroaching in the textblock, the only way to keep the glueline from spreading completely is to immobilize the spine completely. This gives us the most strength, but frequently the resulting book is hardly useable. However, to some degree we can limit the stretch at the glueline by carefully selecting the materials and methods we use to control the spine. Though perfection is hard to achieve the best compromise will be achieved by understanding and designing around the concept of the pivot line.
Controlling the spine - glue The amount of control required is a compromise between what the paper requires and the effect the binder wants to achieve. Without addressing the issue of ideal control I would like to isolate various methods by which we can control the spine beginning with the glue. As mentioned previously, all things being equal a stiff glue will control the spine more than a elastic glue. All things being equal a thick layer of glue will control more than a thin layer of glue. Cold emulsion PVA glues are seldom built into controlling thicknesses. Two identical textblocks, one uncased and the other cased in. Note the amount of control added by the case.
On the other hand, hotmelt glues can be used in varying thicknesses to add control. Hotmelt glues, however, come with their own set of problems. Because they set quickly they are generally unsuitable for fan-gluing and are used primarily for edge gluing. With hotmelts we cannot get the extra strength at the point of leaf attachment that we can get with fan-glu- ing using a PVA adhesive. Secondly, though hotmelts allow us to control the spine by simply thickening the application, when used as the primary means of page attachment they do not allow us to easily control the pivot line. The thicker the hotmelt, the farther the pivot line moves from the point of page attachment. Hotmelt adhesives can be suitable as a method of page attachment, but only where the the spine is fixed or highly controlled. Because the pivot line is often too far from the point of leaf attachment, the flat opening of a hotmelt binding will usually split the book. The split may not be cataclysmic, but it will expand the glueline beyond its elastic limit and, at the very least, leave a gap in the text where the opening was forced. As there is a variety of PVA adhesives so also there is a wide variety of hotmelts. Of these my knowledge is sparse. I have done some tests using a simple glue gun with stick glue to lay beads across spine of textblock. This adds control but at the cost of raised cords (see illustration). Ideally a flat coat of even thickness would be better. Furthermore, the hotmelt I used adhered poorly and popped off after some use. The poor adhesion may be a function of either the way it was applied (laid on with no pressure working it in) or the glue itself. But my very basic experiments indicate that though hotmelts may be less than ideal for leaf attachment, there are probably hotmelts that would make an excellent choice for controlling layers on the compressive side of the pivot line. Though PVA adhesives do not build easily, the effective thickness can be increased through notching. Notching is a method whereby small, shallow grooves or â&#x20AC;&#x153;notchesâ&#x20AC;? are cut into the spine perpendicular to the length of the spine. In a larger commercial operation the notches are usually milled with a machine and are often vee shaped. 62
In a smaller hand-binding operation the notches are often cut with a fine tooth saw and are rectangular. Notches can be cut at varying frequencies along the length of the spine. Whereas the extra strength of a notched binding is frequently attributed to the extra length notching adds to the glueline, I believe the added strength comes from stiffening of the spine. Notching effectively alters the structure of the spine as does sawing the spine and gluing in strings. If you took a piece of paper that was 15” long (we’ll say it is 2” wide) and added a series of little accordian folds across the width about a 1/16th inch deep, at sufficiently close intervals such that the length of your accordianed paper was now 10” long you will have approximated the glue line of a notched binding with a 10” spine. This “glueline” is 15” (the length of our unfolded paper) though the end to end length of the “spine” is now 10”. Think about the accordianed folded paper in your hand. At 15” length it flexed easily across the width. With the accordian folds the paper has stiffened across its width. We have corrugated our piece of paper and added rigidity perpendicular to the length of the paper. We experience this type of structural strength everytime we use corrugated cardboard. Notching effectively corrugates the spine of the book, adding rigidity to the spine. The concentration of glue in the notches essentially creates many small cords and further enhances this effect. The advantage of notching over actual cords is that the cords remain slightly elastic (assuming some elasticity in the glue), the depth of the cords can be less than actual string cords, and it is easy to add them at frequent intervals. The added length of the glueline probably has little to do with the increased strength notching seems to add to a binding. A very close, magnified inspection of the inside gutter of a notched binding frequently shows that as the book is used, the cord of glue in the notched area works itself free of the paper to which it is supposed to be attached. This makes sense since these PVA cords represent a salient beyond the remainder of the glueline which sets slightly back. However, this brings us back to tests of notched bindings that do show improved strength. So, what does notching do to add strength if it is not the length of the glue line? Just as corrugated paper adds rigidity 63
to cardboard by adding thickness, so I would say it is the added rigidity of the notched structure that contributes to the durability
of the page attachment. In addition to adding control to the spine, notching positively affects the placement of the pivot line. Since the overall thickness of the notched spine encroaches into the textblock, the pivot line probably moves closer to the point of leaf attachment.
Controlling the Spine - Liners and Cords With a fan-glued binding, notched or otherwise, I can think of no case where we would not add a cloth liner. The cloth liner serves two and possibly three functions. First it integrates with our PVA and reinforces the spine. Without the cloth liner the strength of the textblock is the strength of the glue between two sections. Once the cloth liner is added, the strength of the textblock becomes the strength of the cloth. Second, the cloth liner provides the structural connection to the boards or cover of the textblock. And third, the cloth liner, particularly if it is strong and inelastic, establishes the limit of the pivot line. If the cloth has sufficient tensile strength such that it will not stretch with the opening the Case Failures textblock, and the glue on the leaf attachment side is elastic, Both of these books have unyieding case the pivot line generally will not spines and uncontrolled textblocks. In the move beyond the liner (though top sample the case itself failed. In the bottom sample the hinge joint failed. In the combination of glue, paper both books the potential energy of the and liner may actually keep the open book exceeded the strength of the binding. 64
pivot line slightly inside the liner). In addition to the structural strength of the cloth liner, we must consider the thickness of the liner. As with the glue or anything else we add to the spine, the thicker it is the more control it exerts and the more it affects the placement of the pivot line. Ideally a very strong and very thin liner is the most effective. If the book is designed to open flat (a small radius opening) it is particularly important that the liner be as thin as possible and that nothing further be added after the cloth liner. Should our book require a larger radius opening (as would be the case with many coated papers) we can add control by thickening the spine. Ideally everything added after the cloth liner should be compressible in nature. This is easier said than done. Traditionally, paper is often used as a liner. Paper stiffens the spine but is not actually compressible. An examination of most any used book that has a paper liner will show that the paper bunches and delaminates where it compresses. These delaminations become memory points to which the book will easily open and will tend to be the points most prone to failure. Once we begin thickening the spine it is important that our method of control remain consistent over time. As paper liners delaminate over repeated uses they become an ineffective means of control. If not paper then what are the alternatives (assuming a perfectly compressible, adequately adhesible and infinitely layerable hotmelt is not in your toolbox)? For papers, such as thin coated papers that drape well, but still require slightly more control than a single cloth, I would simply double the cloth liner being sure to glue thoroughly both under the second liner as well as on top of it to ensure that the PVA permeated both liners to form a single thickened layer. The cloth combines with the PVA to build a compressible thickness. Achieving this requires cloth liners that are sufficiently porous to allow the wet adhesive to bleed through. I also experimented with a 5 mil Mylar J (a glueable mylar whose competitive equivalent is Mellinex 454). Though Mylar is not typically 65
found in bookbindings it has some Quarter-Joint Hinge wonderful properties that I find From peel to pull useful. It has the ability to add a durable, flexible stiffness. Once paper folds or creases it delaminates at the fold and will not return to its former stiffness. Unlike paper and board products, mylar resists In a traditional tight joint stress The loose hinge in folding and creasing. Because of concentrates as a peeling stress at quarter joint case gives the foredge of the glue joint. This the movement this I used it to build endsheets for relationship is maintained through into rather than resist it the quarter-joint binding (see arti- the full opening of the book with the case pulling out and the corner cle on â&#x20AC;&#x153;Flexible Strengthâ&#x20AC;?). I of the textblock pulling in. thought it might also be put to work controlling the spine. I layered a strip of mylar J between the book fully open stress in a two cloth liners. This added almost With quarter-joint cover runs parallel to as much control as beads of hotmelt, the glue line (endsheets to cover) playing to the strong pull strength of but with a much lower profile (see the glueline. This contrasts with traditional case bindings where the illustration page 60). stress of the opened book tends to exert a peeling force on the glueline.
In addition to thickening the spine outward, we can thicken the spine inward with encroachments into the textblock. As discussed earlier, notching is one means of doing this. We can do this more aggressively by making the notches large enough to accommodate strings or cords. These cords can be of various thicknesses and are glued into the notches. Because cords tend to be inelastic, they add significant control to the spine and can easily immobilize the spine. The thicker, deeper and more frequent the cords the more they limit the motion of the spine. Inserting cords into the textblock affects the opening of the textblock in two possible ways. Should the cords remain fully ad- hered to the pages at their point of foremost incursion, the stress of opening the textblock is absorbed fully at those points rather than distributing along the length of the glueline. The spine on such a book will tend to be unyielding, much like a sidesewn book. 66
Should the cords break free, as the notched gluelines tend to in a notched binding, yet remain part of the spine structure (as in a notched binding) the stress of opening will now be distributed along the entire glueline. However, the inelasticity of the cords effectively moves the pivot line into the textblock inside the point of leaf attachment. Once the pivot line moves into the textblock, this effecively puts the glueline/point of leaf attachment under compression when the book is opened. This would probably be ideal except for the fact that this area is not very compressible. If a bent structure is incapable of compressing on its concave side and incapable of stretching on it convex side it will either not bend at all or, once sufficient force is applied, will break. Generally, the result of cords set into the spine is a spine that will move very little. If our purpose is to immobilize the spine, set-in cords will do the job, but so will hot melt adesives as well as the addition of other stiff materials to the spine. The disadvantage of using cords is that they may be encroaching on very limited margins and there may be aesthetic objections to their appearance in the open book. The advantage is that the force to break such a binding is equal to force
The only variation in the quarter-joint books above is in the joint size of the case. The page pull test results for the top book were double those of the bottom book.
required to break the cords which is quite significant. I would not discount cords completely, but I would suggest that if they are used at all, very thin cords in shallow groves are most likely to give us the control we actually need. Once we begin to control the spine by adding layers it is important to make sure control is sufficient to prevent the textblock from opening flat. As the spine becomes thicker the potential for selfinflicted damage increases. The thicker the spine the greater the spread at the point of leaf attachment. A book with a spine layered for control will often split when forced into a flat opening. Though the split may not actually separate the book in two, it may cause leaf detachment at the point of the split. At the very least it will create a “memory” spot to which to book will tend to open. However, if we are casing in our book with a hardcover, there are other ways to control the spine.
Controlling the Spine with the Case Generally a book is cased in or covered without any thought to the fact that the case might add control to the motion of the spine. Such control is easily seen as we move through the process of binding a book. Open the book while it is still an uncovered textblock and
note the degree to which it opens. Open it again when the binding is complete and again note the degree to which it opens. In most cases our book will not open with the same freedom it opened with as a plain textblock (see illustration). The difference between the two is a measure of how much control the case adds to the the book’s opening. Generally, this added control is incidental to the casing-in and not part of our design process at all. But by understanding what is taking place we can integrate this control into our design process. On any book whose spine flexes on opening, the two shoulders of the spine tend to move toward each other. The movement of these shoulders is a measure of the amount of control in the spine. As discussed in the previous section we can control this movement with various combinations of glue, liners and cords. The book’s cover or 68
case, however, can also control this spread. With proper design we can actually fine tune the case design to achieve most any opening radius to provide the needed control or to support the control already in the textblock spine. When a book opens, in order for the spine to arc, the case must give somewhere. In a normal hollowback book the case spine tends to flex. The amount of the opening arc is limited by the amount of flex in the case spine. The stiffer the case spine the more it will restrict a book’s opening. If the case spine is inflexible the textblock cannot arc. If the forces of opening the book exceed the strength of the materials resisting the opening, the book will fail. In a traditional book with a hollowback case the stress of opening falls on the leading edge of the hinge joints. Frequently these joints will separate giving the book some of the flexibility it needs to open. If the case is unyielding and the textblock is uncontrolled failure is a natural consequence (see illustration page 64). With a standard case design we can control the case somewhat by our choice of materials. The thickness and flexibility of our book cloth can be mixed with various spine inlays to create various amounts of give. However, no matter how we assemble the case, the inherent weakness of the design remains. The ultimate point of stress remains at the leading edge of the hinge joint. This stress can be alleviated by putting most of our control into textblock itself. But this is not always possible or desirable. Building up the spine too much has its own problems. Ideally case and spine structure should work together. I found the quarter-joint case uniquely suited to the job of spine control. Almost 15 years ago I published an article called “Flexible Strength” that looked at the quarter- joint binding and introduced an endsheet construction that made it workable. The purpose of working with the quarter-joint case was not to control the spine but, to actually take the spine out of the control equation and to let a book open freely with no resistance from the case. This was accomplished by not adhering the joint areas of the case to the textblock and making them wide enough to provide the give needed to allow the textblock to open fully. The “quarter” in quarter-joint refers to 69
hinge joints that are one quarter of the thickness of the textblock. Assume a sample book that is 2” thick . Unopened the corners of the spine are 2” apart. If we open such a textblock right to its middle such that it hinges at the point of opening, and allow it to open flat, the edges of the textblock are now side by side with virtually no space between them. There had to be a total of 2” of movement for this to happen. In this particular case, each edge of the textblock moved 1” toward the other side. By creating a joint area one quarter the thickness of the book that is unattached and free to move, the case spine can move out ½” (relative to the textblock) and the outer board can move in ½”. (relative to the case spine) for a combined movement of 1”. Since the movement is the same on both sides there is total movement of 2” and the book opens freely unhindered by the case (see illustration on page 65). So, what does this have to do with spine control? Joint size in a quarterjoint case determines movement and how much a book can open without being hindered by the case. Conversely, a quarterjoint case, because of the stiff binder’s board which lines the spine, cannot allow any more motion than that built into the case. A joint sized less than one quarter the thickness of the textblock limits the opening of the finished book. Getting back to our 2” thick textblock, a ½” joint allows 2” of motion or full opening. However, a ¼” joint would allow only 1” of motion and would prevent the edges of the textblock from coming closer that 1” together. Assuming there is no control built into the text- block of the spine, the case assumes full control by holding the textblock in a state of tension. By adjusting the width of the joints from one quarter the thickness of the spine on down to the smallest manageable joint width our materials will allow, we can almost dial in the amount of control we want in the spine. Instead of quarter-joint case being defined by the thickness of our textblock, it is now defined by one quarter of the amount of motion we want in the spine. The advantage of the quarter-joint construction is twofold. First, and as already mentioned, is the ability to fine tune the amount of control by adjusting the width of the hinge joint. The second advantage 70
is that the quarter joint case plays to the strength of our materials and adhesives. Whereas the stress on a traditional case is a peeling force at the leading edge of the hinge joint, the stress on a quarterjoint case is a pulling force on the edge where hinge meets boards (see diagram below). All things being equal a pulling force distributes stress whereas a peeling force concentrates stress. A quarterjoint design plays to a strength whereas a traditional design plays to a weakness. However, this design does require boards that are adequately stiff and covering and lining materials with good tensile strength. The effect of case design on the strength of leaf attachment can be significant. I tested two sample bindings comprised of a stack of National Geographic magazines. To ensure the compatibility of the samples I made one book from the top half of the magazine and the other from the bottom half for a finished textblock size about 4” high by 5 ½” wide x 1 3/4” thick. The two samples were matched page for page. The pages were fan-glued with Wisdom R1603 glue, a glue that is flexible but of relatively low elasticity (a stiffer, more cohesive glue). Each sample was cased in with a quarter-joint case, the only variation being the size of the hinge joint. The spine of the first sample moved freely (see illustration page 67). Pull strength averaged 13.6 lbs. The spine of the second sample was controlled such that it opened in a gentle arc. Its average pull strength was 28 lbs. Controlling the spine doubled the pull strength. The only difference between the two samples was in the case design. The textblocks were identical (see illustration page 67). This brings us back to the beginning of our article and our microphoto of the coated paper binding. Increasing spine control whether by altering the spine structure or through case design increases durability by protecting the bonds between pages (as measured by page pull testing) in bindings where the adhesive bond between fan-glued pages is problematic. Similar tests to books with uncoated papers showed no significant difference in page pull tests.
The Built-up Spine or Case design When do we control by building up the spine and when do we control with case design? My answer is that we do both. Controlling the spine purely with case design can work with the right materials and design, but with a large book there can be quite a bit of tension in the spine. Putting some control into the spine itself reduces this tension. A quarter-joint case can also be used to limit the motion of the spine such that it does not exceed the control built into the spine itself. For example, when binding books with coated paper, I would often build up the spine to the appropropriate level of control and then match the quarter-joint case to the natural movement of the textblock. The case provides a virtual lock on the motion of the spine that would prevent a user from forcing the book open to the point of damage, as someone might be inclined to do on a photocopy machine. On the other hand, assume a book calls for a tradi- tional case design. Almost all standard case designs tend to unintentionally add control to a book. Having no control in the textblock and nonintended, incidental control in this case frequently leads to delamination of the hinge areas if the book recieves any significant use. Adding control to the spine can alleviate this. Where the case spine is quite stiff (fake raised bands on a hollow leather spine come into mind), putting adequate control into the spine takes the stress off of the case and can prevent the type of case failure pictured on page 64
To Control or Not to Control... The reasons for controlling the spine vary from durability to useability to aesthetics. Whereas a flat opening quarter-joint book may rank high in useability, it may not be the look we want to achieve even if we can do it durably. We should also be aware that the options to control include both less control (toward a flat-opening book) and more control (toward a gentle arced opening or even a fixed spine). Some materials may suggest either. 72
For instance, thick, stiff papers may offer several options depending on the perceived behavior of the end user. As paper gets thicker, a fan-glued binding poses greater challenges. With thicker papers, glue tends to encroach more deeply between the pages than it will with thinner papers. This combined with the stiffness of the papers usually requires significant An edge glued. stiff -paper (.007â&#x20AC;?) quarterjoint binding. The pages in this binding can be peeled out, but book is quite control to counteract the durable if not abused. stiffness and to protect the bond between the pages. However, if the paper is thick enough (like a 10 mil cardstock) we probably have enough surface on the edge that we donâ&#x20AC;&#x2122;t need glue between the pages. Such a book can be clamped tight, edge-glued with an elastic glue, lined with a single cloth liner and put in a quarter-joint case. The result will be a very flat opening book that will be durable if properly handled. Here is where the perceived behavior of the end user comes in. The pages in such a book are easily peelable such that they can be peeled out from top to bottom (think of a gummed pad) if the user so desires. However, if the user is not inclined to peel the pages out they will remain intact. However, if your perceived user is the general public (such as library patrons) you may not want to offer them such an easy opportunity to lift pages from the book. In this case, you would fan-glue and add maximum control. The end result would be a very stiff binding, but one that would be significantly harder to vandalize. Though I have focused on fan-glued bindings, this is not to imply than fan-gluing is always the solution. Frequently binders do not have the option to choose the paper and format of the book they 73
bind. However, if we could choose, I would recommend that books with stiff heavy, coated papers (such as is found in many artbooks) be printed in signatures, sewn without tapes or cords and cased in a quarter-joint cover. Sewing would alleviate the problems of protecting the glue joint between the pages (which are unnecessary in a sewn binding) and the need to control the spine. Avoiding cords or tapes will keep the pivot line close to the point of leaf attachment so the book could open freely without undue expansion where the signatures meet. The quarter-joint case will allow the textblock to move freely and open flat. Though sewn bindings are sometimes the best design solution, this is qualified with the understanding that the structural dynamics of the spine apply to sewn bindings also. Understanding the pivot line in relation to different sewing structures can lead to designs that work as intended or, at least, lead to a better comprehension of those that fail. As sewing structures become more â&#x20AC;&#x153;supportedâ&#x20AC;? with tapes or cords, the pivot line moves away from the point of leaf attachment and the need to control the spine becomes greater, lest the sewing itself becomes a leveraged force of destruction.
Conclusion How a spine is controlled affects how a book works, how long it lasts and how it will ultimately fail. The simple attachment of a bookâ&#x20AC;&#x2122;s pages at the glueline cannot be understood simply as a relationship between glue and page but as a relationship between the page and the entire book structure. Traditionally, spine control is seldom considered in the design process but is the incidental result of the methods and machinery at our disposal. The techniques I have proposed in this article are few, but hopefully the ideas are enough to encourage a greater comprehension of the dynamics of the working book as a basis for experimentation and better book design.
Postscript After I concluded this article, I was rummaging through my samples in search of several I wanted to re-photogragh and came across the mylar test book above. I originally put this together to show that with sufficient control you can glue most anything. The mylar in this sample is not Mylar J (the glueable mylar) but the more commonly found Mylar D (which is barely glueable). Mylar D represents a worst case scenario. It has a high drape factor and any glue apllied to it can be peeled off when dry. However, this sample works (though it does require at least one hand to keep it open). I fan-glued the Mylar textblock with an elastic glue (Wisdom R150), lined it three times with a cotton super using a stiffer glue (Wisdom R160 ) to consolidate the supers, and finally added a layer of hotmelt to thicken the spine. P
Single Leaf Binding by Nick Cowlishaw (Cowlishawbookbinding)
Emil Lumbeck, a German Bookbinder, introduced the double fan binding process in the 1930's. Each leaf is secured to the other with a fine line of adhesive applied when the single leaf text block is in a fanned position. To increase strength, thin cords can be recessed diagonally across the spine after the adhesive application in a process known as band driving. The Lumbeck technique can be carried out with the use of a finishing or small lay press. A protective waste sheet of clean paper, followed by a thin flexible card, is placed on each side of the book. The book is knocked square on the spine and head and placed in the press with a centimetre of the spine proud of the cheeks. This can easily be achieved by inverting the press and positioning it on two one centimetre thick pressing boards. If the foredge of the book protrudes beyond the bottom of the press it will have to be supported on blocks when it is turned over to the upright position.
It is at this stage that the cord recesses can be made. Four diagonal cuts are made across the spine using a fine saw held at a 45O angle to create an inverted flowerpot like cavity, a two-ply sewing cord should be of adequate thickness to fill the cavity. Two fine saw cuts at head and tail can also be made to accommodate a thin sewing thread simulating the kettle stitch on a sewn book.
After sawing, the book is raised in the press until between two and three centimetres of the foredge are gripped by the cheeks. The book is pushed over until it touches the side of the press first one way and then the other and reversible PVA applied in each fanned position.
After the adhesive applications the book is lowered back down into the press until one centimetre protrudes and the cords and threads are pushed into the saw cuts. It is possible to round the spines of these books, prior to inserting the cords and threads, by removing the wet adhesive from the saw cuts with a knife and allowing the spine to partially dry before removing thebook from the press and rounding the spine on the bench in the usual way. After rounding, the book is returned to the press, the saw cuts re-glued and the cords and threads inserted. When completely dry the book is removed from the press and the thin card and waste sheet removed. The sewing thread is cut off flush with the spine and the cords are cut or frayed out to become part of the binding structure.
Nick Cowlishaw started an apprenticeship in bookbinding at the age of fifteen. After many years hand bookbinding for various companies, he took up lecturing in the craft. Nick taught at the London College of Printing. Today he teaches advanced classes in Craft Bookbinding at Morley College, London. Nick and his wife Charlotte formed their own bookbinding business, Cowlishaw Bookbinding in 1996.
Nick's informative DVD, 'Rebacking a Cloth Binding', published by the Society of Bookbinders is available to purchase from our web site.
Perfect Bound? Jana Pullman (WS Bindery) Perfect binding is the technique of securing loose single pages of a book into a solid text block with an adhesive rather than by means of sewing. A common example of this is the paperback; almost everyone has seen at least one where the binding has failed and the pages have begun to fall out. Less than perfect, the binding with glue is sometimes needed for a book. To aid in the gluing of the edges of the pages I have made a simple jig. Measuring the height of the cross pieces of my laying press, I cut two pieces of book board to this height by the opening between the screws. Then two more boards cut to around 5 inches wide by the length between the screws. I hinge the two boards together on one side with book cloth leaving a small gap between them. I made this
set of boards to use with pages that are 8 1/2 x 11, the most common size I am asked to bind. These boards should lay in the press as seen in the photograph.
They will help to hold the pages together when you put them in the press and provide a surface when gluing and then finally will hold the pages together after they have been glued.
The text block is squared up between the boards with the fore edge is placed inside the press. Check to see that the spine is out for gluing and the pages are squared up to the spine. After the pages are secure put down waste sheets under them as you fold them over to one side. This fans out the edges and when you glue you actually are gluing the sides of the pages at the spine edge. Before gluing, I place another waste sheet on top to keep the glue from going too far on the top page. Brush PVA glue across the fanned edges. Quickly before the glue starts to dry the pages are folded over to
the other side and glued again so both side of the pages are glued at the edge. Sometimes you will hear this kind of adhesive binding called a "Double Fan Binding." After the second side is glued, remove the waste paper and slip wax paper between the pages and the boards of the jig. Bring the pages back upright and clamp the boards around the pages. Let the
glue dry over night in the press and then line the spine and prepare a case as usual to finish the binding. For thicker books, I sometimes give the text block a slight rounding by using a cardboard tube under the press so when I put the pages and board in the press they shift over the curve of the tube. You do
Double Fan Adhesive Binding Susan Angebranndt (Green Chair Press)
Quick and easy, the double-fan adhesive or millennial binding is a great solution for turning single sheets into an extremely durable paperback book that opens flat and stays open. Its strength comes from the way the pages are glued, using a double-fanning technique that brings glue just a millimeter or so into the textblock. And its “openability” comes from a pop-off spine that moves independently of the textblock. I learned this method from notes by Dominic Reilly, who learned it from Gary Frost. Currently conservator for the libraries at the University of Iowa and author of the Future of the Book blog, Frost is renowned for devising conservation bindings based on enduring mechanical features of historic bindings that he has “deconstructed” and reproduced. In this particular structure, he sought not only to protect a book’s contents and ensure that it opened flat for easy reading but also to incorporate such modern materials as transfer 85
tape and Tyvek and accommodate laser-printed copies and production editioning methods. I’ve adapted this structure for my food & exercise diary and Sherlock Holmes notebooks. it’s good for anything that needs to open flat — like a calendar or day planner. It can also be used to rebind a favorite paperback book. While it’s an easy book to make, please note that you’ll need access to a guillotine (stack paper cutter) to give the book a final trim. Materials & Equipment Gluing up the spine Attaching the covers Generalized measurements A few notes and resources Materials and Equipment These directions are for a book of approx. 4¼” by 5½” by ¼” thick, before trimming. For all materials used in the book, the grain should be parallel to the spine, or 5½” dimension. 1 textblock of single sheets, 4¼” by 5½” pre-printed (with the first and last pages blank) 2 endsheets, 8½” by 5½”. I orginally learned to make this book with Tyvek endsheets, but colored text-weight paper (not cover stock) also works 1 spine covering, 1¼” by 5½”, made from Tyvek or Japanese mending paper. 2 pieces of cover stock, 4¼” by 5½” 1 spine piece, made of cover stock, 1¼” by 5½” 1 cover, made of Tyvek, decorative paper or bookcloth, 8-7/8 by 5½”. I made my first double-fanned adhesive books with painted Tyvek covers. My current technique is to cover the textblock with plain Tyvek, then cover it again with decorative paper. The Tyvek 86
makes the book stronger, especially in the areas it gets most wear — the joints next to the spine Equipment you’ll need: waxed paper, bone folder, straight edge/ruler, white glue (PVA if you have it), scrap paper, glue brush or small sponge paint roller, X-acto knife, weights (heavy book will do), guillotine for final trim. You’ll also need a way to hold the textblock together while you glue the spine — see Step 1 below. Gluing up the spine 1. Jog the textblock edges on your work surface to even up all the pages. You’ll need to keep the textblock together while you glue the spine. To do this you can put it in a finishing press, spine end up, with about 1/3 of it sticking out. You can make a simple finishing press using these directions. Binder clip If you don’t have a finishing press, attach binder clips to the head and tail of the textblock edge. Either stand the block up, balanced on the open binder clips, or lay the textblock on the work surface with the spine extended out over the edge of the table, weighted so that it won’t move while you glue. Whichever method you use, be sure to check carefully that the spine is even, straight and square. 2. Fan the pages over to one side. The textblock should be fanned evenly so all the pages are ever-so-slightly exposed. Work glue (undiluted PVA) onto the surface with a brush or a small sponge paint roller. 3. Fan the pages the other way and brush on the glue again. 87
4. With the textblock upright, squeeze the spine between your fingers to remove any excess glue. Smooth the spine with your finger. Let the glue set up for a few minutes.
5. Take the textblock out of the press, wrap it in waxed paper, put it under weight and let it dry. 6. Fold each 8½” by 5½” endsheet in half lengthwise. For the first sheet, brush a bead or very thin line of glue next to the folded edge on one side only. Tip the glued side onto the front of the textblock about 1/16 back from the spine edge. Repeat with the second endsheet, attaching it to the back of the textblock. Bone down the endsheets.
7. Put the textblock back in the finishing press, spine end up. Glue up one side of the 1¼” by 5½” spine covering, aligning it with the 88
head and tail of the textblock and centering it so that ½” falls on each side of the spine. Work the spine covering into the spine and endsheets with your bone folder and fingers. 8. Take the book out of the press, wrap it in waxed paper, put it under weight and let it dry.
Making and attaching the cover 1. Here’s how to create centered folds in your cover to fit the spine of the textblock exactly: Measure the width of your spine, W” (in our case, ¼”). Make a mark at the top and bottom of the short end of the sheet W” (¼”) from the edge. Fold the opposite short edge to the mark and use your bone folder to get a crisp fold. Turn the sheet around and repeat. Now you have two parallel folds exactly in the middle of the cover, which will wrap perfectly around the spine of your textblock. 2. Glue up the 1¼” by 5½” spine piece and lay it onto the spine fold in the cover. Be sure it is straight and bone it down well.
On left: step 1: fold short end to marks to get the spine fold. On right, step 2, the spine piece is glued into the spine fold.
3. Glue one side of the first piece of cover stock (4¼” by 5½”). It is to be attached to the endsheet on one side of the textblock, 1/16 from the spine edge. Start laying the cover stock down from the spine edge toward the foreedge, smoothing with your fingers and bone folder as you go. Repeat with the other piece of cover stock and other side of the textblock. Put the textblock under a weight and let it dry. 4. Using a pencil and straight-edge, draw a line on the cover stock parallel to and about ¼” from the spine edge. Do this on both front and back sides. This ¼” by 5½” area will not be glued, allowing the cover to pop away from the spine as the book opens. 5. Put a piece of scrap paper between the back cover stock and endsheet. Masking the ¼” by 5½” area at the spine edge, apply a thin layer of glue to the back cover stock. Remove the scrap paper.
6. Lay the 8-7/8 by 5½” cover on your work surface, colored/decorated side face down. Place the glued-up side of the textblock onto the cover, aligned with and to the right of the spine piece. Press on the textblock gently with your palm to set the cover in place. Immediately repeat with the front other cover, pulling snug and square against the textblock. (Don’t forget: put a piece of paper between the cover stock and endsheet before applying glue; and don’t put any glue in the ¼” by 5½” area at the spine edge.)
7. Put waxed paper between the endsheets at both front and back (so excess glue doesn’t stick to anything) and press under light weight until dry. 8. You’re almost done. Trim the book in the guillotine. Do a minimal trim, taking off as little as possible, starting with the foreedge, and then the head and tail. Finished books. To the left are books that I’ve made using this technique. I covered the spine with a piece of red paper, and then added decorative paper over the Tyvek.
Generalized material list For a book W” x H” x S” thick (before trim): 1 textblock of single sheets, W” by H” by S” thick 2 endsheets, (Wx2)” by H” 1 spine covering (S+1)” by H” 2 pieces of cover stock, W” by H” 1 spine piece, S” by H” 1 cover, (S + Wx2 + 1/8)” by H” Notes Grain direction Tyvek doesn’t have a discernible grain direction. For the cover stock, spine piece and textblock paper, it’s important that they all have the same grain direction, running parallel to the spine. On most paper, such as 8½” by 11 printer paper, the grain is parallel to the long side. To make a book 5½” by 8½”, you can’t just chop or fold printer paper in half; the grain will be in the wrong direction. However the grain direction for the 4¼” by 5½” in these directions is just right for printer (letter-sized) paper. Glue for the spine While you can use regular white glue for the fan gluing part of the procedure, PVA (polyvinyl acetate) is better. PVA is an extra strong white glue and is available in small bottles online at Hollander’s, Daniel Smith and Dick Blick amoung others. Or buy in larger quantities from Colophon Book Arts Supply or Talas Online . Rebinding a paperback book To use this technique to rebind an existing perfect bound book, first chop off the existing spine (which will also remove the covers) with a guillotine. Be sure the book is square in the guillotine — old 92
worn paperbacks often arenâ&#x20AC;&#x2122;t square and the spine will come off on an angle. Cut the new covering material a bit bigger than the resulting text block and trim them once you have rebound the book. Other resources Gary Frostâ&#x20AC;&#x2122;s transfer tape binding is described here and here. Pete Jermann has a tutorial for a similar method, another for rebinding a paperback, plus a page of related How-Tos using fanned adhesive bindings. He also sells a fan-gluing press, an aligning device for making fan-glued bindings. Indiana University has instructions for rebinding a paperback using the double-fan method. Atomic Publishing sells several machines for making perfect bound books, using hot glue. Thereâ&#x20AC;&#x2122;s a video on the website showing how it works.