| Pre-Press & Design | Jaina Offset Team
How to Prepare Print-Ready Files – A Complete Guide
One of the most common causes of delayed print jobs and unexpected costs is receiving files that are not print-ready. As a commercial printer that produces lakhs of pages every month, we see this regularly — and it is almost always avoidable.
This guide covers everything your design team needs to know before sending files to us (or any offset printer).
1. Set Up Your Document Size Correctly
Always set your document to the final trimmed size — the size the printed piece will be after cutting. Do not work at a different size and scale later.
- A4 book page: 210 × 297mm
- A5 book page: 148 × 210mm
- Standard catalogue: 210 × 297mm or 200 × 200mm (square)
- Diary pages: Confirm exact size with your printer before starting layout
2. Add Bleed and Maintain Safety Margins
Bleed is extra artwork that extends beyond the trim edge. It ensures there is no white border if the cutting machine is slightly off-register. The standard rule:
- Bleed: Extend all background colours, images, and full-bleed elements 3mm beyond the trim edge on all sides.
- Safety margin: Keep all critical content (text, logos, important images) at least 5mm inside the trim edge.
If you are designing in Adobe InDesign, set bleed in the Document Setup. In Illustrator, set the artboard with bleed guides. In CorelDRAW, use the bleed settings in Document Properties.
3. Use CMYK Colour Mode — Not RGB
RGB is a screen colour mode (used for monitors, phones, websites). CMYK is the colour mode used in offset printing (Cyan, Magenta, Yellow, Key/Black). Always design in CMYK from the start.
If you submit an RGB file, your printer will convert it — and the colours can shift significantly. Bright oranges, greens, and blues often look very different in print compared to screen. Convert your document to CMYK before exporting.
If you have specific brand colours, provide Pantone codes alongside CMYK values for reference.
4. Use a Minimum of 300 DPI for Images
Images that look sharp on screen at 72 DPI will appear blurry and pixelated when printed. The minimum resolution for print is 300 DPI (dots per inch) at 100% final print size.
Key points to remember:
- Scaling a 300 DPI image larger reduces its effective resolution — always source high-resolution originals.
- Vector graphics (SVGs, AI, EPS) are resolution-independent and always print sharply — use them for logos and icons wherever possible.
- Check image resolution in Photoshop under Image > Image Size, ensuring "Resample" is unchecked.
5. Embed or Outline All Fonts
If you use a font that is not embedded in your file (or outlined), your printer's computer may substitute a different font — completely changing the layout. To avoid this:
- InDesign/Illustrator PDF export: Make sure "Embed All Fonts" is checked in the PDF export settings.
- Illustrator files: Convert all text to outlines (Type > Create Outlines) before sending the native file.
- CorelDRAW: Convert text to curves before saving or exporting.
6. Export as PDF/X-1a or PDF/X-4
PDF/X is a subset of PDF specifically designed for print exchange. It ensures all fonts are embedded, colours are in CMYK, and transparency is flattened (PDF/X-1a). If you are using transparency effects or overprinting, PDF/X-4 is preferred.
In Adobe InDesign, go to File > Export > Adobe PDF (Print), and select the [PDF/X-1a:2001] or [PDF/X-4:2008] preset.
7. Check Black Text: Use 100% K, Not Rich Black
For body text, always use 100% K (pure black: C0 M0 Y0 K100). "Rich black" (e.g., C60 M40 Y40 K100) is good for large black areas and backgrounds, but if applied to small text it can cause misregistration and blurry edges.
Pre-Flight Checklist Before Sending Your Files
| Item | Requirement |
|---|---|
| Colour Mode | CMYK (not RGB or Spot unless agreed) |
| Bleed | 3mm on all sides |
| Safety Margin | 5mm from trim edge |
| Image Resolution | Minimum 300 DPI |
| Fonts | Embedded or outlined |
| Black Text | 100% K only |
| File Format | PDF/X-1a or PDF/X-4 preferred |
| Page Size | Matches agreed finished size |
When in doubt, share your file with our pre-press team before finalising — we will flag any issues before plates are made, saving you time and money. Contact us to send your files for a free pre-press check.