How should I prepare my cover for printing?
To obtain a professional cover that perfectly fits your book, it is important to prepare it with the correct measurements, bleeds, colors and spine thickness.
Here's how to send it to ensure a clean, high quality result in HD toner.
🟪 1. The cover page should be indented 3 mm all around.
All covers - even if they do not have border backgrounds - must include:
➤ 3 mm bleed per side
This avoids:
- Unwanted white edges
- Errors due to minimum cut-off variations
- Misalignment in high-volume printing
📌 If your cover page measures 15 × 23 cm, the file should be measured like this:
15.6 × 23.6 cm (including bleeds)
🟪 2. How to prepare the file?
Your cover should be sent in:
✔️ print-ready PDF
✔️ Resolution 300 dpi
✔️ Colors in CMYK
✔️ Final size EXACT
✔️ Embedded fonts
This format ensures that your cover is printed with true colors, correct borders and no typographical errors.
🟪 3. How to prepare the complete front cover (front + spine + back cover)?
This is the most professional presentation.
Your file must include:
| Back cover | Spine | Front cover | Front cover | Back cover | Back cover | Back cover | Back cover | Spine | Spine | Front cover | Front cover
All in one PDF only, with indentations included.
🟪 How do I calculate the spine of my book?
The thickness of the spine depends on:
- Total number of pages
- Type of paper
- Grammage
- Margin for hot-melt glue
We use this simplified formula:
Spine (mm) ≈ (Pages × paper thickness) + 0.5 mm
Examples of approximate thicknesses per page:
- White bond: 0.05 mm
- Cultural bond: 0.055 mm
- Couché matte 130 g: 0.06 mm
- Couché glossy 150 g: 0.07 mm
📌 For complete examples and practical table, see:
👉 Item #21: “How many pages must my file have to match the spine?”
🟪 5. Alternative option: send front and back cover separately
If you don't know how to calculate the spine or you prefer us to assemble it, you can send it to us:
- Cover (final size + bleeds)
- Back cover (final size + bleeds)
- Final interior PDF
And we generate the right spine.
🟪 6. What cover sizes do we recommend?
Depending on the type of book, these are the most commonly used:
📘 Letter size books
21.5 × 27.9 cm (+ 3 mm of bleed)
📘 Half Letter
14 × 21.6 cm (+ 3 mm bleed)
📘 A5
14.8 × 21 cm (+ 3 mm bleed)
📘 Personalized square books
E.g. 20 × 20 cm, 21 × 21 cm (+ indentations)
The final size is entirely up to the author's choice.
🟪 7. Final Recommendations
- Always use 300 dpi
- Exports in PDF/X-1a if possible
- Check that the spine is centered
- Keep texts at 7 mm from edges
- Avoid placing text on the spine line.
- Uses CMYK for faithful printing
🟪 Useful links to prepare your cover page
- Book printing
- How to configure files (Item #19)
- How to calculate the back (Item #21)
🟦 Conclusion
For professional printing, prepare your PDF cover with bleeds, 300 dpi, CMYK and in the exact final size, including front cover, spine and back cover.
You can use our simplified formula or let us calculate the spine based on your internal file.
