Cover image to print PDF

Which colour option?

• IngramSpark: its guide says cover images must be CMYK with total ink no more than 240%, and recommends PDF/X-1a. It converts RGB files to CMYK before printing, which can shift colours. Choose CMYK.
• KDP: its cover guide says images "should be in CMYK color to ensure your cover looks good in print". It doesn't say an RGB cover is rejected. CMYK is the safe choice.
• Lulu: its printers prefer sRGB, so keep the colours as they are.
• Bookvault: asks for a CMYK workflow where possible.

Checked 4 October 2026 on each platform's own pages. More in RGB, CMYK and colour errors.

What the CMYK option does

It converts your colours the way design software does, with a colour profile: GRACoL 2013, the current US standard for printing on coated paper (Lulu's guide names its 2006 version). Then it keeps total ink to 240%, IngramSpark's limit, by lightening the coloured inks in the very darkest areas. No printer publishes the exact profile its presses use, so this is a close, standard conversion rather than a match for one machine. Bright blues, greens and pinks change most whoever converts them: order a printed proof before you publish.

Before you upload

• If your designer worked on top of the platform's template, the guide lines must be hidden before the image was saved.
• Leave the barcode area clear unless you put your own barcode there (make one free).
• Check the PDF in the print file checker: it draws your platform's guides over your cover.

Why the size has to match

The spine's width comes from your page count and paper, so the whole cover's width does too. If the image is the wrong shape, it was made for a different page count or trim size, and stretching it would squash your artwork. The converter tells you and doesn't make the PDF. The spine width calculator gives your designer the exact size and a template.