Our printer requires that the final page of a book be completely blank, so they add a blank page during pre-media setup of your print files. Our printer needs the final page blank to add an internal production tracking bar code to that page. This bar code is used to scan the book interior during book binding to be sure that the correct cover is matched to the correct book interior. (This production bar code is unrelated to and should not be confused with any ISBN or UPC bar codes.)
Depending on a book's size, the final page count of a book must be evenly divisible by either 4 or 6. Therefore, it is best for you to submit book interiors that are one page less than an evenly divisible page count, so the printer can add the blank page at the end and then print the book at that page count. Otherwise, the printer may have to add additional blank pages to the end of the book in order to make it appropriately divisible and thus printable.
The following table summarizes whether a book type and size requires a page count divisible by 4 or 6.
|6.14" x 9.21" and smaller||6|
|6.69" x 9.61" and larger||4|
For example, if you submit a 6.14" x 9.21" book (whether hardcover or softcover), a page count such as 107 is ideal. The printer will add a blank page to make it 108 which is evenly divisible by 6, so the book will print at 108 pages. If you instead submitted the book at 105 pages, the printer would add a blank page to make it 106, which is not divisible by 6 and would therefore need to add two additional blank pages to get to 108, the next highest number evenly divisible by 6.
Back matter (back-of-book ads or promo pages) for your other titles is an excellent way of filling out page count.