Binding Processes

Wire Stitching | Perfect Binding | VeloBind®
Loose Leaf Binding | Spiral Binding | Plastic Comb Binding
Double Loop Wire Binding | Sewn Case Binding | Sewn Soft Cover Binding

A variety of methods are used to bind multiple pages of a digitally printed application. Some methods may be accomplished as an online operation which reduces the overall cost of the application, while other methods must be performed off-line and therefore add another step to the workflow as well as additional cost.

Wire Stitching

Wire stitching is divided into two categories: saddle wire and side wire stitching.

Saddle Wire Stitching


Saddle stitched books are constructed with sheets that each represent four pages of a book. A page is printed on the left side of the sheet and a page is printed on the right side. The back side of the sheet is also printed this way, which creates a printed sheet containing four pages of a book. The sheets are stacked with other sheets in the correct page order and then stapled along the fold line, or saddle. The stapling is accomplished on equipment that cuts staples from a continuous roll of wire mounted on the machine. The machine inserts the wire staples into the fold line of the stack of sheets. Some machines can accomplish the folding and stitching in one operation. There are several digital press models that include online stitching as an option. Many booklet manufacturers use this multiple task equipment to increase efficiency and reduce the expense of producing the print project.

Types of Saddle Wire Stitched Covers

There are two types of saddle wire stitched books that are most often used for booklet production: the standard cover and the self cover.

Saddle Wire Stitching Limitations

Saddle stitched wire binding is effective for volumes up to 128 pages (32 sheets, printed with 2 pages front and back), but only if the paper stock is thin enough. It isn't practical to saddle stitch books with more pages than 128 pages. There can even be problems when attempting to stitch fewer pages than this if the paper stock is heavier. You may find that 64 pages is the maximum for heavier stocks.

The limitation on the number of pages that should be contained in a saddle wire stitched book is due to a phenomenon called page "creep". Page creep is a characteristic of booklet binding in which the inner sheets stick out farther than those closer to the outside due to the paper thickness. When the edges of the booklet are trimmed flush after stitching, the width of the innermost sheet will be the narrowest in the book, with each successive sheet being wider than the next one (working from the inside of the book to the outside). The printed area of each page will appear to get farther from the outside margin, as you go from the inside of the book to the outside.

To compensate for page creep, the pages are "shingled", which means that the inner margin, or "gutter," is increased on the pages working from the inside of the book to the outside. The gutter is successively wider page-by-page. The outside page has the widest gutter and the inside page has the narrowest gutter. Increasing the gutter moves the printed area closer to the outside margin. When the pages of the book are trimmed flush, the printed copy appears to cover the same portion of each page. This procedure is not normally performed on booklets with only a few pages because the effects of creep are minimal on such publications, however it should be considered on booklets that approach the page maximum for saddle wire stitching.

Side Wire Stitching

Digitally printed applications that are bound with side wire stitching are generally booklets or books that contain too many pages to be effectively saddle stitched. The problem of page creep is not an issue because the sheets are individually folded prior to binding (they are not stacked together prior to folding) and they are bound in a stub area on the side of the book. A wrap around cover is usually bound to the pages. The staples are inserted from the front side of the book, through the pages, and are pinched closed on the back side of the book.

Side wire binding does not allow the book to be opened as flat as a saddle stitched book and an extra allowance for the inner margin must be made when the application is printed to allow for the stapled stub. Covers for side wire books are usually scored so that they can be opened easily and neatly. The binding area is often covered with decorative tape, not only to hide the staples, but also to provide added strength to the binding and make the book easier to handle (the staples will not catch on other books if tape is applied).

Perfect Binding


A popular method of binding books printed with digital technology is perfect binding. It is one of the most automated of the binding processes, which makes it inexpensive. The low cost makes it an extremely popular choice for binding a variety of books. Perfect binding is used to bind many types of publications including magazines, catalogs, paperback books, and telephone directories.

Perfect binding is an easy and inexpensive method of binding single sheets into a book. Many digital books are printed as stacks of single sheets rather than groups of folded sheets (signatures). The single sheets are gathered, stacked, and placed in special equipment in which the binding edge is covered with glue. A cover is attached to the book and is held in place by the glued spine. The title and other pertinent information are often preprinted on the area of the cover that attaches to the binding edge. Perfect binding is most successful when the paper grain runs parallel with the spine of the book.


Books that are perfect bound must have square backs, smooth spines, and adequate binding strength to prevent the pages from being pulled from the binding. In the past, the only way to accomplish this was with large off-line production machines, which required lengthy make-ready periods and resulted in very expensive short run applications. The large off-line machines were better suited to larger print runs.

An alternative to the large off-line binding devices is smaller, less expensive, off-line perfect binders, which are specifically designed for small digital print applications. They have the capability of producing perfect bindings that are of nearly the same quality as the bindings produced with the larger machines. The overhead cost is much less than the larger machines and the make-ready time is greatly reduced.

Some digital printing devices are equipped with finishing units that are capable of performing the perfect binding online. This makes the process of completely a printed book much more efficient because it eliminates a step from the workflow, which saves time and expense.


Perfect binding can be divided into three categories according to the specific process that is used: hot adhesive, cold adhesive, and thermal binding.


1. Hot Adhesive Perfect Binding

Hot glue is the most widely used of the perfect binding adhesives. Books are usually 1/4" up to 2 1/4" thick depending on the thickness of the substrate. A major disadvantage with hot adhesive is that the book cannot lie flat when it is open. The binding will break if too much pressure is applied in attempting to make the book lie flat when it is open.

2. Cold Adhesive Perfect Binding

Cold glue is not used as often as hot glue because it is more expensive and requires more time to cure than hot glue, but it is stronger and more flexible. When the cold adhesive is used in conjunction with a scored and hinged cover, the book is able to lie flat when it is open and the binding will not crack. Books with cold adhesive perfect bindings range in thickness from 1/8" to 2 1/4".

3. Thermal Binding

Thermal binding is similar to the hot adhesive method of perfect binding in that adhesive and heat are used to form the binding, however, rather than using hot glue, an adhesive strip is used as the material for binding. Pages are fed into a machine where the adhesive strip and a wrap around cover are applied to the binding edge of the pages. Heat is used to secure the adhesive strip and cover to the pages.


There is only one manufacturer for this type of binding, so it is a trademarked brand name. Security strips are used for the binding of pages and it is most often used for legal documents and publications. The equipment used for this type of binding is expensive. Pages cannot be added or removed unless the security strip is cut.

Loose Leaf Binding

Loose Leaf Binding is one of the simplest methods of binding. Cut pages are punched with holes to accommodate the metal rings or posts contained in the binder. An advantage of both ring and post binders is that pages can be added or removed easily. The ring binder also has the advantage of allowing the pages to lie flat when the book is open, making it a good choice for technical or training manuals. It is important to remember the when printing pages that will be bound in this manner that an allowance for the inner margin (gutter) must be made so that the holes punched into the pages will not interfere with the printed area of the page.

Spiral Binding

A spiral binding consists of a continuous wire, which is coiled through evenly spaced holes that have been punched into the pages of a book. The spiral wire can be made of metal, plastic, or plastic coated metal. Plastic is available in a variety of colors, but the metal spiral has a limited color selection. When the books are open, the pages lie flat. The pages can also be folded over completely, which makes spiral binding a good choice for training manuals, cookbooks, notebooks, and calendars.

Diameter Guide for Spiral Binding

The examples below are based on booklets consisting of
20 lb. bond pages and heavy weight covers on the front and back.

Number of Sheets

Approximate Thickness
(including covers)

Coil Diameter

30 (60 pages)


6 mm

40 (80 pages)


7 mm

50 (100 pages)


8 mm

60 (120 pages)


9 mm

70 (140 pages)


10 mm

80 (160 pages)


11 mm

90 (180 pages)


12 mm

100 (200 pages)


13 mm

110 (220 pages)


14 mm

125 (250 pages)


16 mm

140 (280 pages)


18 mm

160 (320 pages)


20 mm

180 (360 pages)


22 mm

210 (420 pages)


25 mm

230 (460 pages)


28 mm

250 (500 pages)


30 mm

265 (530 pages)


32 mm

Plastic Comb Binding

Plastic combs are another binding method that allow for the addition or removal of pages from a book. Rectangular holes are punched into the pages of a book and the pages inserted over the fingers of the plastic comb. A standard 11" sheet has 19 holes punched into it. The plastic combs are durable and come in a variety of colors. Book titles or descriptions can be printed on the spine of the plastic comb so that the book can be identified when it is being stored. The plastic combs allow the book to lie flat when it is open, but the book cannot be completely folded over. Books up to 1 7/8" thick can be comb bound.

Diameter Guide for Comb Binding

The examples below are based on booklets consisting of 20 lb. bond
pages without covers. For booklets with covers, add 1/8" to the comb diameter.

For the number of sheets shown on the left,
use the comb diameter shown on the right.

20 sheets (40 pages)


40 sheets (80 pages)


55 sheets (110 pages)


70 sheets (140 pages)


90 sheets (180 pages)


100 sheets (200 pages)


120 sheets (240 pages)


150 sheets (300 pages)


170 sheets (340 pages)


200 sheets (400 pages)


220 sheets (440 pages)


230 sheets (460 pages)


290 sheets (580 pages)


360 sheets (720 pages)


425 sheets (850 pages)


Double Loop Wire Binding

Double loop wire binding consists of a series of double wire loops from a continuous pre-formed wire, which are inserted into pages that have been punched with square or round holes. The loops of the wire are held opened by a machine to allow the pages to be inserted over the loops. Once the loops are closed, extra pages cannot be added.

Double loop wire binding is more expensive than plastic combs or spiral binding, but it is more attractive and long lasting. When books with this type of binding are open, the pages lie flat and the pages can be folded over completely. Double loop wire works best for books of one-inch thickness or less. Many technical manuals and cookbooks have this type of binding and they are very popular among architects. Double loop wire binding is also known as "Wire-O-Binding", which is a brand name for this type of binding. Listed below are the types of wire available.

  • 3:1 Wire

    With this wire, the paper is punched 3 holes per inch, which is 32 holes per standard 11" sheet size. It is available in sizes ranging from 3/16" up to 9/16" in diameter. It has the best appearance of all double loop wire.

  • 2:1 Wire

    Pages are punched with 2 holes per inch or 21 holes per standard 11" sheet size. 2:1 wire is used for binding books that are too large for 3:1 wire and is available in sizes ranging from 5/8" to 1". The wire is more durable and sturdy than 3:1 wire.

  • 19 Loop

    The pages are punched with 19 rectangular holes per standard 11" sheet size and the wire comes in diameters ranging from 1/4" to 1". The wire is similar in appearance to 2:1 wire.

Diameter Guide for Double Loop Wire Binding

The examples below are based on booklets consisting of
20 lb. bond pages with heavy weight covers on the front and back.

Number of Sheets

Approximate Thickness
(including covers)

Double Loop Diameter

45 (90 pages)


1/4" (3:1 Wire)

60 (120 pages)


5/16" (3:1 Wire)

75 (150 pages)


3/8" (3:1 Wire)

90 (180 pages)


7/16" (3:1 Wire)

105 (210 pages)


1/2" (3:1 Wire)

120 (240 pages)


9/16" (3:1 Wire)

135 (270 pages)


5/8" (2:1 Wire)

160 (320 pages)


3/4" (2:1 Wire)

190 (380 pages)


7/8" (2:1 Wire)

220 (440 pages)


1" (2:1 Wire)

Sewn Case Binding

Sewn case binding, also known as "edition binding", is the most expensive binding method, but is the most durable. It can be used for any book thickness, but the most common thicknesses range from 1/4" up to 3". A number of steps are required to complete a sewn case bound book, so much of the process is automated to increase efficiency and reduce costs. The following steps are typical of the process employed with sewn case binding.

  • A large printed sheet containing 16 or 32 individual book pages, called a signature, is cut, folded, and assembled in the correct page order.

  • The signature is sewn together with other signatures.

  • Endleaf papers, which are usually made of heavier stock than the other pages of the book, are glued to the outside of the first and last signatures.

  • The book is trimmed on all sides except the sewn binding side.

  • The sewn edge (spine) of the book is coated with glue.

  • The spine of the book is rounded in a special machine to allow the cover of the book to function properly when it is attached to the pages.

  • A strip of gauze is wrapped around the spine of the book.

  • The cases (covers) that will be used for the book are made from heavy board stock with its grain running parallel to the spine of the book, which prevents warping of the cover. The heavy board cases are wrapped with embossed paper, cloth, plastic coated material, leather, or a variety of other materials (occasionally a combination of materials) to form the final book covering.

  • The book is attached to its hard case/cover on a casing-in machine, which glues the endleaf papers to the case.

  • The final step is to insert the book into a hydraulic press to ensure that it dries properly and does not warp.

Sewn Soft Cover Binding

Occasionally the pages of a book are attached to paperback or soft covers with the use of strong thread, which is sewn through the pages and cover using special equipment. This binding method is often preferred for technical manuals and textbooks the books need to withstand the constant wear and tear of being repeatedly handled by number of people. A sewn soft cover is more durable than perfect binding or wire binding in which the overuse of a book may cause the binding to fail quickly.

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