Book Preflight, Explained › Who needs book preflight?
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Who needs book preflight (and what each person should check)
Every print book gets checked by the printer. What changes is which rules are most likely to catch you. Find the line that sounds like you.
Anyone uploading a print book to KDP, IngramSpark, Barnes & Noble Press or Lulu needs preflight. The highest risk is for first-time authors, authors switching printers or paper, and hardcover, color and picture books.
"This is my first book, and I'm using KDP"
Your biggest risks are the ones nobody warned you about: a cover without bleed, a PDF made at letter size, margins that are too small by the spine, and a spine width you guessed. KDP's previewer will catch some of these, but it won't tell you how to fix them. Start with the checklist, then read our first book guide.
"My book is on KDP and now I want IngramSpark too"
This is where good books get rejected. IngramSpark's rules are stricter: 0.5" safety margins on every page (KDP allows less on the outside), a 240% total ink limit, its own spine width (its paper is different) and a different barcode box. A file that passed KDP can fail IngramSpark on day one. Read why it passed KDP but failed IngramSpark.
"I'm changing paper, page count or trim size"
Every one of these changes your cover size. Going from white to cream paper makes a 300-page KDP spine about 0.074" wider. Adding a chapter changes the spine. A new trim size changes everything. Re-check the cover and margins each time. See the cover size chart.
"I'm making a hardcover"
Hardcovers have extra pieces: a case wrap that folds over boards, and maybe a dust jacket with flaps. Each piece has its own size, its own hinge or fold areas and its own "no text here" zones. A dust jacket book can need three files: case, jacket and interior. Hardcover rules, explained.
"My book has color pictures, or it's a children's book"
Color and full-page pictures bring the most rules: pictures must be 300 DPI, art that touches the page edge needs interior bleed, and dark pictures can go over the ink limit. Picture books also tend to use fonts and effects (shadows, see-through shapes) that need flattening. Check picture sharpness and transparency first.
"I'm a black and white novel or non-fiction book"
Your risks are fewer, but sneaky: "black" text saved as RGB color, a blue link left in the text, a colored logo on the copyright page. Black and white printers treat all of these as color. How to make it truly black and white.
"I help other authors" (formatters, small presses, coaches)
If you send files for clients, one rejection costs you time and trust. Run every client book through the same checks, every time, and keep a record of what passed. SparkPrep's report lists every check, for the printer you chose, so you can hand the client proof that the files were checked.
Find out what's wrong with your files before the printer does
SparkPrep checks your cover and every interior page against the exact rules Amazon KDP, IngramSpark, Barnes & Noble Press and Lulu use, tells you each problem in plain English, and can fix it for you.
Scan my book free See how SparkPrep worksThe scan is free and shows how many problems your files have. To see every problem and where it is, the audit is $1.99 ($3.99 after January 1). The Advanced Audit checks every page, up to 300, for $9.99.
Questions people ask
Do experienced authors need preflight?
Yes, mainly when something changes: a new printer, new paper, a new page count, a new trim size or a hardcover. Each change can break a file that passed before.
Is preflight harder for children's books?
Usually yes. Full-page color pictures need 300 DPI, interior bleed and an ink limit check, and effects like shadows often need flattening.
Free help from SparkPrep
Last updated 2026-11-01. Written by Joshua Davis, founder of SparkPrep. Numbers come from each printer's own published guides; always double-check your printer's current rules before you upload.