If your publication is very thick you should make inner margin wider than usual.
Explain inside outside and gutter margins.
Also keep in mind that prepress imaging at the printer or pod vendor is going to also account for creep in the thickness of the book by moving page images away from the spine to account for the thickness of folded signatures.
However one of your margins will need to be bigger than the others and that is the inside margin otherwise known as the gutter.
This means that the top of the page will alternate from outside on verso pages to inside.
The gutter margin is a typographical term used to designate an additional margin added to a page layout to compensate for the part of the paper made unusable by the binding process.
This particular book happened to be fairly thick 356 pages so i set the gutter to 0 3 inches.
That is what you see in the photo.
In a facing pages layout word refers to this type of layout as mirror margins the gutter margin is on the very inside of both pages.
In practice there is no difference between the gutter margin and the inside margin since both refer to exactly the same thing.
The reason for this is that books do not lay flat when they are opened.
There are spots there for you to set up your left margin your right margin and your gutter.
By convention landscape pages whether recto or verso are oriented with the top of the page to the left.
The pages have to bend out from the spine.
A standard is to set the left and right margins at a half inch each and to then have a quarter inch gutter.
Top bottom and outside margins and a 1 25 inside margin or a 1 margin and a 0 25 gutter on your portrait pages.
As the pages disappear towards the binding the.
To make it easier for the reader to read the text you should prevent the type from hiding in the gutter.