InDesign page margins, safe margins, two-page spreads.
Take a closer look at InDesign page margins, safe margins, and two-page spreads. They are topics that self-publishers should understand, and especially understand in relation to how the books will be printing.
InDesign page margins
There are quite a few graphic design books that discuss page sizes and margins. Some are confusing. For instance, often books show a diagram of a two-page spread with inner margins that are quite narrow and wide outside margins. That makes for gorgeous white space.
But from a practical point of view, the print book with a hefty page count, may be difficult to read. To read the text in the middle of a thick book with narrow inside margins, you may have to push down the text pages, and in the process, break the spine. Consider the final page count when planning page margins. In this case it makes sense to make the inside and outside margins equal.
There are two more layout considerations though. If the outside margins are not wide enough, the text appears too close to the page trim. There is no set rule for outside margins.
The solution is to test, creating several pages with different margins and filling the pages with placeholder text. Most importantly, print out the pages. Do not overlook trimming the page to size. Put a half point (0.5-point) rectangle on the page dimensions to use as a trim guide to see on the page that is printing out, or use the crop marks. It is surprising at how trimming the page will change the look.
Either allow an image to bleed, or give it a substantial margin. Avoid the mistake of having an image that is only a quarter inch from the trim. This is an example of a page that might look good on the computer screen. But, when printed full size on press and trimmed to size, the mistake of having an image too close to the trim is apparent.
Print-on-demand services instruct you to use “safe” margins. There is no need for high-quality book printing providers to require safe margins, as books are printing on commercial printing presses and in signatures.
POD services are usually outputting a page or two at a time from a digital output device. It is high-end equipment by copier manufacturers and does what desktop copiers do. They need the safe margin because paper sometimes jostles around when outputting pages.
Also, POD services need to make sure they have enough margin for side-sewn hardcovers. Professionally printed books are never side-sewn. They print on press in signatures and professionally bound.
The two-page spread
A spread is one or more images together in a grouping that are the width of two pages. It crosses over the gutter of the book. There are many self-publishers who come to our company to print books having “printed” a book at a POD service. They often want assurance that two-page spread images will not clip off or be lost in the gutter, as it may do at a POD service.
No clipping on books printing on press
This clipping will not happen on the books we print on press and here is why. When pages are output a page or two at a time at a POD service, the entire stack of single output pages, binds together by side-sewing. However, books often have two-page spreads. The center of the spread image may be clipping off in the gutter, when using a POD service. It happens when a book is side-sewn or is binding with glue, so that some of the image is simply not seen.
This loss of part of the two-page spread image will never happen when books are printing on press in signatures. The size of the signature depends on the number of pages as well as the size of the sheet. Star Print Brokers always prints on sheet-fed presses, never on web presses using roll stock, and never using digital output devices.
The signature sheet may have for example, six pages on one side of the sheet and six pages on the other side to make up a 12-page signature. The sheet then folds down to the signature size, like a booklet. The booklet-like signatures are then “married” together to form the text block of the book. The printing process is the same for a hardcover book or a soft cover book.
If the book must be print-on-demand, then design it without any two-page spreads crossing over the gutter. If you do not do this, spreads will be clipping in the middle as shown in this photo of a dog.