Print File Setup for Self-Publishing a Picture Book

The distance between a finished illustration on your iPad and a book a child can hold is not artistic. It is a stack of unglamorous technical decisions: trim sizes, bleed margins, color profiles, file formats, and one upload form. Diana McDerMott, who has illustrated 23 children's books, spends the final part of her Twotap course walking through every one of them, and her message up front is that the stage feels intimidating mostly because it is less creative, not because it is hard.

This post follows her print production process end to end: the vocabulary a printer expects you to know, her actual file preparation workflow out of Procreate, and what the Kindle Direct Publishing upload really looks like.

Trim, bleed, safe zone, spine

Four terms carry the whole lesson. Trim size is the finished size of your book after the printed sheets are cut down; everything in your illustration is designed relative to that cut line. Bleed exists because the cut is not perfectly precise: every trim has a margin of error around a sixteenth of an inch, so any art meant to reach the page edge must extend about an eighth of an inch past the trim line. Without bleed, a slightly off cut leaves a white sliver along one edge. The safe zone is the mirror image, a margin about an eighth of an inch inside the trim line where anything critical, especially text, must stay so it cannot be cut off. And spine width is the one dimension you cannot know in advance, because it depends on page count and paper; the print on demand platforms calculate it for you once the interior is final.

Two more requirements sit alongside these. Work at 300 DPI minimum from the very first canvas, and export at full resolution, because a screen will happily show you a sharp image that prints soft. And check which file format your platform wants before you export: usually a PDF, sometimes specifically PDF/X-1a, the standardized flavor that embeds fonts and flattens transparency, occasionally TIFF or JPEG for ebooks. Knowing before the upload fails, she notes, saves a lot of frustration.

From Procreate spreads to a print PDF

McDerMott's own pipeline runs Procreate to Photoshop. She exports her spreads as PSD files, airdrops them to her computer, and converts each one from RGB to CMYK via Edit, Convert to Profile, choosing US Web Coated SWOP v2. The conversion flattens the layers and visibly dulls the image, especially the blues, and she is upfront that the CMYK version looks drab on screen but prints correctly. The discipline is in the saving: always save a copy into a separate CMYK folder and never overwrite the original.

Because KDP prints perfect bound books, pages cut and glued into the binding, spreads have to be split into single pages. For her 8 by 10 inch book that means cropping each half to 8.125 by 10.25 inches, and she names each file with its page number so the PDF assembles in order later. There is a Procreate specific trap here: at 300 DPI, Procreate refuses to make a canvas exactly 8.125 inches wide, rounding it to 8.127, and some platforms reject dimensions that are even slightly off. Rather than wrestle with it she crops in another program entirely, and she demonstrates the same workflow in Canva, where you can type exact inch dimensions, snap each half of a spread into place, and export a PDF with an optional CMYK setting on the Pro tier.

The PDF itself she compiles in Photoshop with File, Automate, PDF Presentation, sorted by filename, quality set to Press Quality, then checked against KDP's 650 MB file size limit. Then comes the step she refuses to skip: open the finished PDF in two page view and read the whole book, checking page order, the seams across spread centers, and errors one more time.

You can't have enough eyeballs on this thing to make sure nothing slips past you.

Diana McDerMott, "Exporting Interior Pages for Print" (Part 6, Lesson 19), From Manuscript to Printed Book

Before this tedious stage she has her authors do a final error check, reads the book aloud herself, and hands it to her sister for one more pass.

What the KDP upload actually involves

On Kindle Direct Publishing, a few decisions matter more than the rest. Choose paperback: at the time of recording, Amazon only offers hardcover for books of 72 pages or more, which rules out standard picture books. Choose premium color interior with white paper, the right option for full page color. Set your real trim size, because the form defaults to 6 by 9. And tick bleed if your art reaches the page edge.

ISBNs are simpler than they sound. You can buy one at bowker.com, or let KDP assign you a free one during setup; either way the platform can place the barcode on your cover automatically, so you never have to buy a barcode separately. The cover itself is one flat file wrapping back cover, spine, and front cover, built from the platform's template once the spine width is calculated. Keep all cover text in the safe zone, keep spine text large and legible if your book is thick enough to carry any, and resist the temptation to just reuse an interior illustration, which she calls a pretty weak cover; hint at what is inside and make the reader curious instead. One modern wrinkle: KDP requires you to disclose AI generated content, and McDerMott asks her students plainly to be able to answer no for their images.

The built in previewer flags anything outside the safe zone before you can proceed, and then the pricing page does honest math with you: her demo book costs $4.20 per copy to print, so a $9.99 list price returns $1.79 per sale, numbers worth playing with before launch.

Always order the proof

Her firmest rule comes at the end. Before hitting publish, order a physical proof copy. It arrives with a watermark and cannot be sold, but it is the only way to check what the screen cannot show: whether anything important sits too close to the trim, how the colors landed, how the gutter swallows the middle of each spread, whether the spine text reads. If you fix anything, order another proof. Only then publish, and allow up to 72 hours for the book to go live, which matters if you are timing a launch. After that, author copies at print cost, $2.84 each for her demo book, are how you stock a craft fair table without paying retail for your own work.

Print production is Part 6, the final part, of Diana McDerMott's From Manuscript to Printed Book on twotap.art. The course starts much earlier, with pagination, character design, storyboarding, and color, and ends here, with a proof copy in your hands. As she puts it, it is one thing to see everything on a screen and another to actually hold it.