Tag Archives: bookbinding

A Guide to Swell

In bookbinding, the term “swell” describes the thicker area of a book block at the spine due to the addition of sewing thread. It depends on factors detailed below, but a binder or conservator generally does not have control over all these variables. Knowing how to estimate the amount of swell that will develop is one of the most important aspects when planning to sew a book, since it corrolates to the degree of round and the shape of the shoulders that a book will end up with.

Different binding styles need different amounts of swell. Too much swell creates a textblock that is unstable, squiggly, and difficult to back. Too little swell and there are insufficent shoulders which are necessary for some styles of binding. In all case binding structures, there is more leeway with amount of swell, and as long as it is not excessive it will be sucessful; with bound books the tolerances are much tighter. For example, if you are resewing an existing text block it is critical the new shoulders exactly fit the original boards.

Softer, multi-ply threads afford much more control of swell while sewing as compared to a hard modern thread. Currently, I primarily use threads sold by Colophon Book Arts, including the Colophon Best Blake Thread and the Londonderry Linen Lacing Cord #4. Both can be deplyed if desired to make them thinner. I also prefer to support smaller, specialist bookbinding supply companies. If you are using standard threads, 25/3  is a reasonable starting place. 

Many early binding structures—even up to the late 18th century—manipulate the shape of the boards to fit the spine, rather than the modern fine binding tendency to fit the boards to a 90 degree shoulder.  This makes it easier to fit a wider range of boards to a given swell. Obviously, this is not an option for many binding structures.

There is no formula, instead these ten aspects need to be considered:

1. THICKNESS OF THREAD. Thick thread (or more plys) = more swell. Thin thread (or fewer plys) = less swell. Although not ideal, the thickness of thread can be changed during sewing if too much or too little swell develops. 

2. HOW HARD OR SOFT THE THREAD IS. Hard thread does not flatten in the signatures = more swell. Soft thread flattens in the signatures = less swell. A compressible thread gives more control. It is often advisable to untwist hard modern threads a bit to make them softer by running them through your fingernail and thumb, and let them relax.  Waxing thread also makes it harder, so I generally avoid it if possible. Sometimes excessive kinking and twisting comes from using too small of a needle. Softer thread can fray more during sewing, though. 

3. THICKNESS OF THE TEXT PAPER. Thick paper absorbs more thread = less swell. Thin paper absorbs less thread = more swell.

4. HOW HARD OF SOFT THE PAPER IS. Soft paper absorbs more of the thread = less swell. Hard paper absorbs less thread = more swell. It is easier to control swell with softer paper. Guarding the spine will increase swell. Washing and resizing can also affect how much swell develops. Swell can also be adjusted before sewing by beating or otherwise compressing the sections.

5. HOW MANY LEAVES ARE IN EACH SIGNATURE. More leaves can absorb more thread = less swell. Fewer leaves = more swell.

6. HOW MANY SIGNATURES THERE ARE. More signatures = more swell. Fewer signatures = less swell. Some binders like to visualize this by wrapping the thread around a pencil the same number of times as there are signatures.

7. SEWING STYLE. All-along, two-on, three-on, etc. All-along produces the most swell, more “-on” sewing styles = less swell. Packed sewing produces more swell due to a small overlap of thread. This can be controlled, to produce naturally packed sewing, which has one length of thread on the cords for each signature.

8. SEWING SUPPORTS. Tapes, cords, thongs. Tapes produce the least swell, cords and thongs slightly more since the thread can overlap slightly inside the signature. Supports also differ in the amount of adjustment that can be done after sewing, ie. how much the thread can move on the supports during consolidation and backing. A professional sewing frame, such as the Nokey makes this easier.

9. HOW MUCH CONSOLIDATION IS PERFORMED DURING SEWING. More consolidation during sewing= less swell. I have often observed students sewing identical text blocks, with identical thread, end up with significantly different results. A loaded stick, or knocking down stick can help with compression, although some people prefer to use a bone folder or wedge shaped piece of wood.

10. TIGHTNESS OF SEWING. Tighter sewing makes a thinner book before pressing. Looser sewing can develop due to improper tensioning or too large of a needle. A book sewn too tightly can develop a “banana” shape, thinner at the kettle stitch. Even tension is crucial.

Best practice: sew with the thickest thread possible.

News from 1886: Hand Bookbinding is Slowly Disappearing

“Bookbinding on a small scale seems to be one of those minor industries which are slowly disappearing. Yet we think that there is always a certain need of a good bookbinder in every country town. We recollect how such a person was once maintained in a small European city by official work, and now and then a few orders from the country gentlemen. Shopkeepers and farmers as a general rule are not bibliophilists. When, however, we come in this country to look upon a book as something of intrinsic value, we will insist on real books, in proper shape and goodly binding, and then the bookbinder’s day will have come.”

The Bookmaker: A Journal of Technical Art and Information, January 1886, p. 16.


Thinking About Making: You, Artifact and Tool


A work-in-progress diagram of the interactions that take place when performing a craft.

I’ve been thinking about using tools for a while now, starting in 2004 with a preliminary (and upon rereading inadequate) exploration in Vol. 1, No. 1 of The Bonefolder. Since then, the cultural literacy of tool use continues to decline. In fact, I often encounter people who think they can pick up any tool and it will work fine without any evaluation, prepping, sharpening, maintenance, etc.  If nothing else, thinking a bit more about tools before using them can lead to more successful craft outcomes.

This work-in-progress diagram summarizes some of my thinking. David Pye’s concepts of “workmanship of certainty” and “workmanship of risk” fit nicely into it; technique forms a continuum between you and the tool, not residing completely in one or the other. In paring leather, for example, using a schar-fix or Brockman paring machine involves relatively little technique from you, but resides mostly in the machine. Of course, you still have to know when to use it, and set it up and maintain it. Failure is often catastrophic, it usually works well or it doesn’t. This is the nature of the machine.

A middle ground between you and the tool might be the spokeshave.  Although a 151 spokeshave needs to be modified to work well, it is safer and quicker than using a French or Swiss knife to scrape the leather. It requires more skill to use than a paring machine, but accidents are usually small tears, or sometimes chatter, rarely catastrophic, can lead to uncomfortably small small pieces of leather.

The most risky way to pare leather overall is with a French or Swiss knife.  The locus of technique is almost entirely dependent on your skill.  It takes a steady hand and a lot of practice, but I have seen binders become suprisingly adept at it. Similar to the paring machine, failure can be catastrophic, like cutting a hole in the middle of the spine. All three of these methods of paring are not mutually exclusive, often they are all used by the same binder for various purposes at various times.

There is also room for conservation work in this diagram. Your intention on the artifact is much more limited due to ethical considerations about preserving existing information inherent in the artifact, there often has to be more creative thought put into material selection and tool use. If you are paring the leather on the original spine of a book that will be rebacked, there is little or no margin of error. A loss becomes a loss of information in the artifact. You can’t buy another one. Your tools have to work perfectly.

Materials also place limits on an original design. Often beginners want to experiment with something new, unique or unusual.  There is nothing wrong with this, but it is usually much more difficult than performing a craft activity in a more traditional manner. Unusual materials can require unusual tools.

One of the joys of craft is when the three elements in this diagram are so integrated that we think through the tool and into the artifact. It becomes embodied, a natural extension of our hands.  We often call this muscle memory, or getting a feel for something. Again to use a paring example, when you are competent, the leather pares down quite simply and easily without much conscious thought. When you first learn to pare leather, you need to conscious of how hard, soft, stretchy and thick the leather is, how sharp your knife is, the blade angle of the knife, the bevel angle of the knife, the angle you hold the knife at, where you start the cut, and the amount of leather you are cutting at one time.  This is a lot to keep track of.

I think many of us forget how much of an interplay there is between these three elements. It is important to remember that when things are not going right in any craft, it is not completely your fault, or the tool, or what you are making: it is usually an inter-relationship that can take some time to sort out. That’s one reason why we take classes to learn things.

To be continued….


Delrin Lifting Tool


Top of Delrin lifting tool. The tip is sharp for about an inch on each side. The rest of the tool edges are rounded for a comfortable grip..


Detail of the general shape of the tip.


Detail of the gradual reduction in thickness at the tip.

This delrin lifting tool is useful for general lifting, mechanical backing removal, and whenever you need to gently pry or delaminate something. Both book and paper conservators will find this an essential component of their toolkit. Although it is thicker than the carbon fiber lifter I make and sell, it has a slightly lower coefficient of friction, so slides a bit better, and it is more ridgid. If you like your teflon lifter but are tired of how easily the cutting edge bends, this might be the tool for you. Obviously, it is not as durable as metal.  But it is always great to have as wide of a range of tools as possible.  These delrin lifters are hand sharpened to achieve the best possible balance between initial cutting performance and edge retention. The edge is easy to maintain by sanding or scraping. Click on “Tool Catalog” above for ordering information.

DELRIN LIFTING TOOL.  Around 12 x 1 x .125″.  $40


The Importance of Papryus in the Sixth Century

In the sixth century, Cassiodorus wrote this wonderful description of the impact of writing on papyrus on the thought process:

“Before [papyrus was discovered] the sayings of the wise, the thoughts of the ancients were in danger. For how could the writer have been able to write quickly, when, the hardness of the bark resisting him he would scarcely have been able to be ready? The excitement of the mind submits to the unfitting hindrances; when the words are harassed, the mental powers are compelled to grow lukewarm … This was fit only for the beginnings of the world. Then papyrus was discovered, and therewith was eloquence made possible … So smooth and so continuous, the snowy entrails of a green herb, which keeps the sweet harvest of the mind, and resorts it to the reader whenever he chooses to consult it; which is the faithful witness to all human action.”

-Elspeth Whitney, “Paradise Restored: The Mechanical Arts from Antiquity through the Thirteenth Century”, Transactions of the American Philosophical Society 80, Part 1, (1990): 67.

Book Slate

Nelson’s School Series Book Slate for Home and Student Use (London & Edinburgh: T. Nelson and Sons, [1900?]) is an odd structure, a diptych in a case binding. The exterior looks like a standard quarter cloth case binding with printed paper sides. The interior, however, is made from a painted slate-like material. It can be written on and erased. The earliest known diptych is from 14th-century BCE, making the codex seem like a newbie.  Is the laptop a 20th century iteration? Long live the diptych!

book slate

Nelson’s Book Slate. Exterior front board. This is a well used, but largely intact book. My Collection.

book slate 2

Nelson’s Book Slate. Open. Chalk marks of addition and subtraction. My Collection.

Sobering Statistics Concerning Book Conservation

There are some sobering statistics in The FY2014 Preservation Statistics Report, by Annie Peterson, Holly Robertson, and Nick Szydlowski.  Eighty-seven cultural institutions responded; primarily academic libraries. Although the authors caution about extrapolating the data since the respondents were self-selecting, I find it difficult not to view the results as roughly indicative of general trends in libraries. The most striking finding is the steady decline in the money spent for bound volumes.

The treatments reported tend to be quite utilitarian, more aimed at circulating rather than special collections. For example, a Level 1 treatment takes less than 15 minutes, a Level 2 between 15 and 120 minutes, a level 3 more than 120 minutes. Most conservation treatments for special collections materials take much longer than 120 minutes.

The authors report that “from 2000 to 2014, total conservation treatment of bound volumes declined faster than commercial binding; treatment declined by 77% in that period, while commercial binding declined by only 69%.”  This survey includes in-house and outsourced conservation activities: 92% of respondents had at least some type of in house conservation program, and 70% outsourced at least some treatments. In all, the survey encompasses the treatment of 1.6 million items.  The only growth area is a slight—though not dramatic— increase in spending for digitizing and in reformatting of audiovisual materials.

No, the sky is not falling, but as a book conservator, it is worrisome to see these trends. Frankly, I don’t see the situation changing significantly in the coming decades, until we reach the point where the book and the text have become totally individuated. Then, hopefully, the book will experience a reappraisal.

It is well worth reading the full report:  The FY2014 Preservation Statistics Report.