As shown above, the punches for the spiral extend approximately 0.27" in from the spine edge. Therefore, this has to be taken into account when setting up the margins for a spiral book and added to the desired margin of the design.
For example, if a 0.5" margin is needed, then the margin on the spine edge would be 0.5" plus 0.27" for binding, for a total of 0.77", but only on the spine. On the other three edges, the margin would be 0.5" to give the illusion that the content is centred. The reader's eye will basically ignore the part of the page that is covered by binding.
Also, the spine edge alternates on the "even" and "odd" pages. This is independent of any actual page numbers that are added to the artwork, as the numbers can vary based on whether the cover is included, whether there's a table of contents, if there is a section at the beginning that is numbered separately, etc.
If the front cover is "page 1", the inside front cover would be "page 2", etc so for a conventional book that is read from left to right, all of the odd pages starting with the front cover would have the spine on the left-hand side, and all the even pages starting with the inside front cover would have the spine on the right-hand side.
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