Should KDP coloring books use gray-black backing pages?
Short answer: Some coloring book authors place a dark gray or gray-black backing page after each artwork page to reduce show-through when readers color with heavier media. This is a design choice, not an Amazon requirement.
When it can help
Backing pages can make sense for one-sided coloring pages, marker-friendly layouts, or books where the author wants a cleaner separation between drawings. They also add pages, so printing cost and book thickness should be checked before publishing.
How Book Interior Kit handles it
The desktop app includes an optional anti-bleed page setting. When enabled, it can insert a gray-black backing page after each artwork page and include those pages in the local PDF preview.
Always review the final page count, blank-page pattern, and KDP Previewer result before submitting a coloring book interior.
Book Interior Kit is independent software, is not affiliated with Amazon or KDP, and does not guarantee KDP approval.