Skip to content

Folding the Leaves

Cover to Cover: Exposing the Bookbinder's Ancient Craft

As the knowledge of papermaking spread it was discovered that sheets of paper could be folded.  In fact paper was pliable enough to be folded several times.  This process of folding became the first step in the craft of bookbinding.

The true nature of imposture fully displayed in the life of Mahomet... Humphrey Prideaux. 1698.
The signature, shown here as F3, usually appears at the centre bottom of the first page of a folded section.

The binder had no choice as to size or layout of the book and, perhaps frustratingly, the quality of the paper upon which its text was printed.  It was simply their job to follow the publisher’s or printer’s instructions.  Fortunately, when it came to folding, they were guided by what was known as a signature.  This printed identification mark, usually in the form of a letter from the alphabet, appeared at the bottom of the first page of what would become a folded section.  If it did not end up on the outside of a section, the binder could be certain that the printed sheet had not been folded correctly.  An error in the succession of the pagination will also confirm this.  Here’s how the signatures were utilised when making books of different sizes:

The Folio

Comprises sheets of paper, folded once down the centre, forming two leaves and four pages.  The sheets to be folded are laid out lengthwise in a pile.  The signature must be on the lower left-hand corner and on the underside.  A bone folder is taken in the right hand and held at the bottom of the sheet at approximately the centre.  The binder’s left hand then pulls the right-hand edge of the sheet over the folder towards the left.  When a careful check reveals that the print of the two pages facing each other registers exactly, the binder’s left hand holds the sheet perfectly square whilst the right uses the bone folder to crease the sheet – first from the middle upwards and away from the binder, then downwards towards the binder.

Note: each sheet of paper, once folded constitutes a section, with the exception of folios where it is common practice to make up the sections by inserting two or more sheets, one within the other.

The Quarto

Comprises sheets of paper, folded twice, forming four leaves and eight pages.  As with a folio, the sheets are laid out lengthwise.  In this case the signature must be on the underside of the top right-hand corner.  The sheet is folded as in the folio but then it’s turned so that the crease is furthest from the binder and the right-hand side is brought over to the left.  The quarto tends to be an old-fashioned fold, although it is still used for books such as family bibles, dictionaries, encyclopaedias and atlases.

The Octavo

Top: The teflon folder
Bottom: The (cow) bone folder

Comprises sheets of paper, folded three times, forming eight leaves and sixteen pages.  The sheets for an octavo are folded in much the same way as the folio.  The signature again appears on the lower left-hand corner and on the underside.  The bone folder is used to first make a folio, then the sheet is held in the middle of the first fold by the bone folder and, with the left hand, the right-hand corner is drawn over until the pagination of the opposing sheets registers.  The crease is formed by running the folder off the top right-hand corner along to the left.  The final fold is simply a repetition of the first fold as completed for a folio.

There are numerous other sizes and the process for folding them is virtually the same, it’s just the number of folds that changes.

In all books there exists preliminary matter: half title, title, dedication, preface pages etc.  These may run over more than one sheet; they may be printed on odd sheets.  It is the binder’s job to make them into an orderly section.  They may have signatures but unlike the book’s pages of text, these will appear as lowercase letters.  Maps or plates (full page illustrations) are also printed separately from the text, sometimes on different paper.  These must be carefully put in order as per the accompanying list of plates or ‘instructions to the binder’.  Where the plates are not sewn in as part of a section, they must be guarded, that is, pasted in by the inner edge onto a prepared slip of stout paper.  At all times the inscription or title of the plate must be on the right-hand side of the page such that the reader will not have to reverse the book when inspecting the plates.

The signatures used at the bottom of book sections usually take the form of letters from the alphabet.  Occasionally the letters J, V and W were omitted.  This is thought to be a survival of the days when books were mostly printed in Latin and these letters had no separate identities.  In general, the text of the book began with the letter B, as A was allocated to the title and following pages. If a book was long enough to exhaust the alphabet, the sections would continue on as AA to the end of the alphabet and then on to AAA if necessary.  Variations of this form of continuance also included Aa or 2A etc.

The true nature of imposture fully displayed in the life of Mahomet... Humphrey Prideaux. 1698. Catchwords, seen here as "be", appear at the lower right-hand side of the pages.

In books of the 15th-18th centuries it is not uncommon to see catchwords.  Similar to the signature, a catchword assisted the binder in ordering the leaves correctly.  It also confirmed whether the pages were set up accurately in the press.  Essentially the first word of a page, the signature appeared printed under the bottom line (usually on the right) on the previous page, to ensure continuity of the text.  This practice disappeared upon the arrival of the industrial printing press.

This black horn folder is made from Nepalese water buffalo. It's ideal for folding and also scoring and burnishing.

The hand-tool that binders use for folding and creasing sheets of paper is called a bone folder. So named for its composition of bone, usually cow, the folder traditionally measured about 8-9 inches in length and was dull-edged on all sides, with one end slightly more pointed. Old folders were also made of ivory. Today the options for folders are many and varied. Most are still made from bone but some are made from horn (elk, moose, deer, even Nepalese water buffalo), whilst others such as the Teflon folder are entirely synthetic. They are created in all shapes and sizes and assist with not only folding but with turning corners of cloth and leather, scoring paper, burnishing surfaces and in pushing cloth-coverings into slip cases and clamshell boxes. Over time, the bone folder can form to its user’s hand, so the binder might be reluctant to share his or hers with you!

There exists an old standard of sizes most frequently accepted for books.  You may hear the terms: folio, quarto, octavo, duodecimo, sextodecimo, etc.  These names represent the number of pages that the printer puts on each sheet of paper.  In the case of a quarto, there are four pages on each side of the sheet.  It also denotes the number of leaves in a book section, where two pages constitute one leaf.  These names will often appear abbreviated: quarto as 4mo and octavo as 8vo, etc.  Occasionally the ‘mo’ and ‘vo’ are dropped altogether and replaced by a small “o”, as in 4º.  In recent times, these terms have begun to lose their true meaning, and are often used loosely to signify pages of certain sizes, regardless of the number of the pages that were printed on the original sheet.  Below are examples of some book formats and their corresponding sizes:

Name Abbreviations Leaves Pages Size (Inches)
Folio fo. 2 4 12 x19
Quarto 4to 4 8 9.5 x 12
Octavo 8vo 8 16 6 x 9
Duodecimo 12mo 12 24 5 x 7.0375
Sextodedimo 16mo 16 32 4 x 6.75
Octodecimo 18mo 18 36 4 x 6.5
return to top
Did You Know...?

19th century French olive wood paper knife with carved handle depicting a seated man. Note the clean, thin edges and the rounded tip. Its purpose is to gently slice open the folded sections of a book.

In 2016 Ian Spellerberg, the author of Reading & Writing Accessories…, turned what people knew, or thought they knew, about paper knives and page turners on its head.  For years page turners, with their 6-12 inch blades, were thought to have been used to turn the pages of books, magazines and newspapers.  Often described as ‘antique’ or ‘Victorian’, page turners came in a variety of sizes and were frequently ornately carved or decorated.  They were made of materials such as ivory, wood, tortoiseshell and brass but they all shared two common features – a clean (but not sharp) edge and a rounded tip.  Spellerberg had been fascinated by a group of blades that he’d found in a London antiques shop, labelled as page turners.  He started to research them but soon realised that there existed no historical literature on page turners.  What he discovered instead was that a page turner was in fact a paper knife.  Its purpose was to gently tear the unopened sections of a book, created by the binder in the folding process, thereby allowing the reader access to the text.  It came in a variety of sizes; those with 12+ inch blades used for opening newspapers and those made to fit in the palm of a hand for opening miniatures.  For modern books the paper knife is no longer required as machines now trim any uncut pages during the binding process.

Note: A letter opener differs from a page knife.  It was dagger-like in shape with a pointed tip designed to get into the corners of envelopes and open them with haste.  It must not be used for opening the folded edges of book paper, also known as bolts, for its sharp blade may veer off the crease causing unnecessary damage.  Unlike a dull-edged paper knife, the letter opener does not need a crease to cut through paper.

Lee Hayes
May 2018

University Library

Barr Smith Library
South Australia 5005


Phone: +61 8 8313 5224