Preparing PDFs for Print
How to prepare a print-ready PDF for your book — bleed, margins, fonts, and the mistakes that will cost you money at the printers.
Why Print PDFs Are Different
A PDF that looks perfect on screen will not necessarily print correctly. Print PDFs require specific settings that most people never think about until their first print run comes back wrong. Here is everything you need to get it right first time.
Resolution
Screen images display at 72 to 96 DPIDots per inch. A measure of image sharpness for print, minimum 300. Print requires a minimum of 300 DPI. An image that looks crisp on your monitor will print blurry and pixelated if it was not created at print resolution. Always source or create images at 300 DPI minimum.
Colour Mode
Screens display in RGBThe colour format screens use. Printers need CMYK instead colour. Printers print in CMYKThe colour format printers use, made of cyan, magenta, yellow and black ink. An RGB PDF submitted to a printer will have its colours converted automatically — and the results are often dull and unexpected. Always export your cover PDF in CMYK colour mode.
Embedded Fonts
If your PDF uses a font that is not embedded in the file, the printer's computer will substitute a different font. Always export with all fonts embedded. In InDesign, Word, and most design tools this is a standard export option.
Bleed and Margins
Bleed and margins are the two settings that cause the most problems for first-time authors going to print.
What Is Bleed?
Bleed is the extra area of colour or image that extends beyond the edge of the page. When a printer trims your book to size, the blade cuts slightly differently each time. Without bleed, you get a thin white line at the edge of your cover. Standard bleed is 3mm on all sides.
Safe Zone
The safe zone is the area inside your page where important content — text, logos, faces — must sit. Keep all critical content at least 5mm from the trim edge. Anything outside the safe zone risks being cut off.
Interior Margins
Interior pages need a larger inside margin (the gutter) to account for the spine. For a perfect bound book under 200 pages, a gutter margin of at least 15mm is recommended. For books over 300 pages, increase this to 20mm or text near the spine will be difficult to read.
The Checklist Before You Send
Run through this before submitting your PDF to any printer.
Cover PDF
CMYK colour mode. 300 DPI minimum. 3mm bleed on all sides. All fonts embedded. Spine widthThe thickness of your books spine, based on page count and paper weight calculated correctly based on page count and paper weight.
Interior PDF
All fonts embedded. Correct trim sizeThe final cut size of your printed book after trimming matching your chosen book size. Gutter margin appropriate for page count. All images 300 DPI. No RGB images. Page numbers present and correct.
Final Check
Order a single proof copy before your full print run. No checklist replaces holding the physical book in your hands. A proof copy costs £15 to £30 and will catch errors that would ruin an entire print run.
Need Help Preparing Your Files?
We have experience preparing print-ready files for local printers. Get in touch if you need guidance.
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