Self-published paperbacks: make your line art PNGs non-transparent!

(Writing up my self-publishing process — I won’t have had new problems, but nobody will have had my precise problems. I realised I should Just Write, then index it all later. So let’s start deep in the details.)

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To publish a paperback book through Amazon’s CreateSpace or Kindle Direct Publishing services, you can submit either a Microsoft Word document — which the system will attempt to auto-format in some sensible manner — or a print-ready PDF of the interior.

(I used CreateSpace. KDP’s print service is very beta … I tried to use it, but strongly disrecommend it — it’s not good yet, and doesn’t do author proof copies.)

A book is not just a slab of text, but a designed object — you need to make it look nice. If you want something that looks professional, you’re going to do a PDF, with everything laid out just so.

CreateSpace and Kindle have a previewer, to show how your file will be rendered by their systems. So I prepared a nice print layout in LibreOffice, made a PDF with “Export as PDF” — then concatenated three PDFs with pdfjam, ‘cos I was being fussy and exacting — then uploaded it to CreateSpace, previewed it, and … well:

 

 

Here’s how the tulip looked in the original PDF (pages 146–147) and in Kindle’s previewer:

This was somewhat disconcerting. Fortunately, the CreateSpace user forums are very helpful, with a post from someone with similar apparent problems.

The root cause: transparency in PNG images.

PNGs are lossless — JPEGs are fine for photos, but you risk getting JPEG artifacts if you use them for line art. However, PNGs allow transparency.

When you include images in your LibreOffice document, LO doesn’t mess with them — it tries to include them as-is, unaltered. The PNGs had transparent bits — and the CreateSpace previewer didn’t handle it well.

The images would almost certainly have printed cleanly! But problems should always be fixed as early in the production chain as possible — and you can’t be sure some other system won’t choke on it. The rule is: get the source file right. So:

1. If you have black-and-white line art, make your PNGs 1 bit per pixel with no transparency, before you include them in your document.
2. Make them 300dpi if you can — more is a waste, and may get dithered or screened.
3. When you “Export as PDF” from LibreOffice, export as “PDF/A”.

CreateSpace’s checker still found some transparency in the PDF, but the print version came out fine.