Even though you can (and should) use the same interior file (as long as it’s also the same trim size and binding type) for KDP and IngramSpark, spine width is a domino effect of three factors:
- page count
- paper thickness
A 308-page book using cream paper will have a .77″ spine width for KDP and will have a .691″ spine width for IngramSpark.
You will have to prepare one cover for KDP, which will look like this…
and a separate cover for IngramSpark using their specific template, which will look this.
Amazon KDP has updated their cover calculator for both paperback and hardback bindings.
Go to KDP’s Online Cover Calculator.
For IngramSpark, you will need to know the ISBN of your project, and the cover template will be emailed to you. It will not be displayed immediately like KDP’s calculator.
Go to IngramSpark’s Cover Template Generator.
Instructional Video on How to Create and Export a Book Cover in Adobe Indesign
This video will show you how to set up and export a book cover in Adobe InDesign. I don’t recommend Photoshop for book cover compilation because that is not the right tool for the job. For starters, you are unable to individually manage or export each page of the cover (front, spine, back, dustjacket flaps, etc.). Second, Photoshop tends to export a more bloated PDF than InDesign.