Humans have been binding pages together since the second century. Bindery is a true testament to our desire to organize information and package it for convenience and safe-keeping. Modern bindery has some terminology that is good to know and modern bindery also has some pitfalls, the same pitfalls that have been around for nearly two thousand years!
Number of Pages Believe it or not, this can get kind of crazy… the counting of pages. I have had customers who only count the printed pages, not the blank pages and customers who count the number of sheets of paper as the number of pages. Needless to say this can get very confusing when your are receiving quote specifications. When you count pages the total page count must be an even number. It is impossible to have a physical document with an odd number of pages. Both sides of a sheet of paper are counted. When referring to the page count, you do not count sheets. Instead, you count pages. Each sheet has two pages.
The parts of a page, head and foot, recto and verso.
Signatures A signature is a large sheet printed with a multiple of four pages. When it is folded, it becomes a section of the book. Signatures can be any multiple of four pages, but 8, and 16 are the most common for letter size pages.
Imposition Imposition is the arrangement of pages on a press sheet in the proper order and orientation for the formation of signatures. Knowing imposition is important when designing features such as crossovers or large solid color areas on which you want exact color matches.
1. Design around Creep
Binding by stapling sheets together where they fold at the spine is called saddle stitching. Saddle stitching is economical and practical but has the disadvantage of creep. Your saddle-stitched booklet may have a cover that is thicker than the pages (this is referred to as pages plus cover) or the cover can be the same weight as the pages (this is referred to as a self-cover). You can have as few as eight pages saddle stitched or as many as 100 depending on the thickness of the paper. When a binding is saddle stitched, the signatures nest inside one another.
Allow for creep in your design. When the book is trimmed to make it even all around, the center pages are going to be narrower than the front and back pages. This is referred to as “creep.” If you are producing a 12-page catalog, the “creep” might not make much of a difference. For instance, if the catalog’s pages are 100# book weight, the bound catalog will be 1/32nd of an inch thick. A graphic element that repeats from page to page (such as a page number/folio) and is 1/8th of an inch from the edge of the sheet will have shifted 1/76th of an inch in the center of a 12-page catalog. Creep is more noticeable in a 72-page catalog, which is 3/16th of an inch thick. In this case, the same element in the center spread has shifted more than 1⁄16th of an inch, or half of the distance between where it was positioned in the center spread and the edge of the page. The diagram below illustrates how noticeable creep can be. If your print provider is using imposition software, this difference will be adjusted in the prepress department by changing the size of the gutter or page width in very tiny increments. (Moving things in imposition is known as shingling). To avoid noticeable creep, place elements far enough away from the edge of the page so that the shift will not be noticeable after saddle stitching.
2. Allow for Gutters
Perfect binding and case binding do not have the same problems with creep as saddle stitch binding, but there are other factors to be aware of. The most critical is the thickness of the finished document. Perfect binding requires a minimum thickness that changes slightly depending on the machinery used and the type of glue. Basically, count on a minimum thickness of 1/8 in. to be successful. If you use fewer pages, you run the risk of the binding not holding together.
Because perfect binding is far less costly than case binding and is similar in appearance, it is popular. Remember that when using perfect binding, the finished product does not lie as flat as books that have been saddle stitched or case bound. Therefore, allow more room in the gutter. “Lay flat binding” is a type of perfect binding with more flexible glue and a score on the cover to facilitate flattening the book, but it still does not result in as flat a product as other binding methods.
When specifying paper for the cover of a perfect bound book, it is preferable that the paper be uncoated on the side that receives the glue, a C1s sheet or uncoated.
3. Case Binding
Case binding involves gluing or sewing the pages together and then gluing them to a spine and cover that is rigid. An end paper holds the spine and cover to the pages. This paper cannot be coated and must be a minimum text weight of 80#. Because of the way smyth sewn books are put together, signatures of different page length add cost. This is why you might see a few blank pages at the end of a hardbound book. It may have been less expensive to just leave them there.
There are more decisions to make when designing a casebound book. In addition to the cover and text paper there is the endpaper, whether the back (spine) will be rounded or flat, and whether or not there will be a headband or endband. Due to the heavier weight of a casebound book, there also might be a need for extra protection for the cover in the form of lamination or a dust jacket.
4. Gatefold Considerations
A gatefold is a foldout that opens to double a page. A gatefold will never be joined end to end exactly where the two edges meet. Therefore, your printer will either leave a very tiny gap between the two edges or overlap the edges slightly. The degree of either measurement will depend on the thickness of the paper. Discuss with your printer how production will manage the gap or overlap and order a paper dummy so you can see the end result clearly before the item is printed.
When designing a gatefold, keep in mind that the thicker the paper, the greater the likelihood it will pop open. Paper up to 65# will lie flat after folding, but nearly every paper thicker than that will tend to lift. Scores made with a steel rule die (die scoring) are often preferred for a gatefold because they yield a sharper crease and more precise parallel folds than rotary scoring made with a wheel.
5. Parallel and Roll-Fold Considerations
Although the panels of a roll fold appear to be divided evenly, that is not the case. For example, a trifold, or letter fold, appears to be divided in thirds, but actually the first fold is shorter than the center panel, and the last fold is longer than the center panel. This gives the finished piece the appearance of being evenly folded because the edges will line up.
The size of the panels will be dictated by the thickness of the paper to some degree. If the paper is thin, 80# book for example, and your design elements are not critical, you may not even need to adjust your art. But if the paper is a thick cover weight and your design elements are critical, then you will need to discuss the width of the panels with your print provider.
If you do not specify the width of the panels in your file, your printer will adjust the width in the bindery stage when placing the trim and fold. The greater the number of panels that roll in, the greater the adjustment required in the design process.