Book Preflight, Explained › Preflight vs. a proof copy
Three checks, three jobs
Preflight vs. the printer's review vs. a proof copy
Authors often think, "I'll just order a proof." A proof copy is great, but it can only show you a book that the printer already accepted. Here's how the three checks fit together.
Preflight is your own check of the files before upload. The printer's review is their automatic check after upload, which can reject the files. A proof copy is a printed book you order to see how it really looks. Preflight gets you through the review; the proof shows the final look.
Side by side
| Preflight | Printer's file review | Proof copy | |
|---|---|---|---|
| When | Before you upload | Right after you upload | After the files are accepted |
| Who does it | You, or a tool like SparkPrep | KDP, IngramSpark, B&N Press or Lulu | You, holding the book |
| Catches | Size, bleed, margins, fonts, pictures, color, ink, spine | Mostly the same things, as pass or fail | How it looks and feels: color shifts, readability, spine centering, typos |
| Tells you how to fix it? | A good one does | Rarely. Usually a short error message | No |
| Cost of a miss | Nothing yet | A rejection, a new upload and another wait | A new proof, more shipping and more waiting |
Why the printer's review isn't enough
The printer's review is pass or fail. When it fails, you get a message like "insufficient bleed" or "content outside the safety area", often with no picture of where. You fix what you think is wrong, upload again and wait again. Authors commonly go around this loop several times. SparkPrep's founder went around it 18 times with his own book, which is why SparkPrep exists. Our rejection messages site explains what those short messages really mean.
Why a proof copy isn't enough
You can only order a proof once your files are accepted, so a proof can't save you from a rejection. And some problems don't show in one copy: a spine that's slightly off-center may look fine in your proof and wander in the next print run, because the printer's fold can move a little each time. Preflight makes sure there's enough room for that movement.
The order that saves the most time
- Preflight both files and fix everything it finds.
- Upload. The printer's review should pass the first time.
- Check the printer's online preview page by page.
- Order one printed proof. Read it with a pen in hand.
- If you change anything after the proof (even one word that moves a page), preflight again before re-uploading.
KDP lets you order printed proof copies for the printing cost plus shipping, and they are marked as proofs. It's money well spent, after preflight, not instead of it.
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
Should I order a proof copy if I preflighted?
Yes. Preflight gets your files accepted. A proof copy lets you see color, readability and feel on real paper. You want both.
Why was my file rejected after it looked fine on screen?
Screens don't show bleed, ink coverage, embedded fonts or true picture resolution. The printer's review checks those, which is why preflight checks them first.
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.