What's inside the print PDF?

A few things happen in the exported print PDF that you won't see on screen but the printer will.

Black text is real black, not four-color black

Your body text is set in DeviceGray black — pure black ink, printed on the black plate alone.

This sounds like a technicality and isn't. If text is specified as RGB black, a print-on-demand press can interpret it as rich black: black mixed from all four inks. Four plates have to line up perfectly, and on a fast POD press they don't quite — so the edges of small letters pick up a faint colored fringe, and a whole page of it reads as slightly fuzzy or muddy.

Grayscale text prints on one plate, so there is nothing to misalign. It's why a professionally prepared interior looks sharper than the same book exported from a word processor.

Your cover is a different matter — it's full color by definition. See Why do printed colors differ from my screen?

Pictures follow the same rule

A picture whose ink is genuinely black and gray — a logo, a drawn scene-break ornament, a line illustration — is embedded in gray, on the black plate, exactly like the text. It costs you nothing.

That matters more than it sounds, because printers price a color interior per page for the whole book, not per picture. One color picture on page 12 of a 300-page novel makes all 300 pages color pages. So the test is worth passing.

Two things to know:

• It's decided by the pixels, not the file. A PNG saved with an alpha channel is technically an RGB file even when every pixel in it is black. That's fine — what's checked is the ink, and pure black ink is embedded as gray whatever the file says.
• The preflight tells you before you upload. If a picture has real color in it, you'll see a warning naming how many — see The export says I have a color picture for what to do about it. Replacing those with grayscale versions keeps the whole book in the cheaper tier.
• "Almost gray" is not gray. The test is exact, because a printer's is. A picture can look perfectly black-and-white and still carry pixels one level off neutral — 6, 5, 5 instead of 6, 6, 6 — which is what image editors and AI upscalers leave behind. That is real color as far as a press is concerned. If a picture you believe is gray gets named in the warning, this is almost always why: open it and re-save it as an actual grayscale image.

Fonts are fully embedded

The typeface files are embedded whole, not cut down to just the characters you used. Subsetted fonts are a common cause of printer rejections and of glyphs quietly turning into blank boxes. The file is larger; it also arrives intact.

Your title and author are in the file

The PDF's properties carry the title and author you set, with BookPublish.app recorded as the producer. Some printers read these, and it's what shows in a PDF reader's title bar instead of a filename.

Worth knowing: this metadata comes from what you typed in the tool, so if the title bar says something unexpected, check your book's title field rather than the file name.

Selectable, searchable text

The text is real text, not an image of text. You can select and search it in any PDF reader, which is also how you can check the file yourself — search for a word from chapter three and confirm it's found.

What isn't in it

• No crop marks and no printer's marks. POD printers don't want them. See Does the export include crop marks?
• No bleed on the interior, unless your book has full-page images that need it. See Does the PDF include bleed?
• No contents page — see Can I add a table of contents?