Preparing your files for printing

It sounds like such a simple thing to do, right? Surely it’s as easy as printing a document from your home printer. Well, maybe so. Or maybe not.

When it comes to professional printing for products like flyers, business cards and banners, there’s certain rules and approaches that must be undertaken in order to yield the best possible results. From understanding your printing trim lines to the difference between RGB and CMYK modes – your complete guide to printing set up is here!

Feel free to save this guide to help you for any future projects.

What is RGB and CMYK?

When you’re getting ready to send a design to print, one of the first (and most important) steps is choosing the right colour mode. This determines how colours are created, displayed, and ultimately reproduced. The two modes you’ll encounter most often are RGB and CMYK, and they serve very different purposes.

RGB – for digital use only

RGB stands for Red, Green, Blue. This is the color model used by digital screens—like phones, monitors, and tablets.

• RGB is an additive color model, which means colors are created by adding light.
• The more light you add, the brighter the color (and combining all three gives you white).
• RGB has a wider color gamut than CMYK, so you can see more vibrant, luminous colors on screen than printers can reproduce.

When to use RGB:
✔ Web graphics
✔ Social media content
✔ Digital ads
✔ Anything meant to be seen on a backlit display

CMYK – for printing

CMYK stands for Cyan, Magenta, Yellow, and Key (Black). This is the standard color model for commercial printing.

• CMYK is a subtractive color model, meaning it works by subtracting light reflected off a surface.
• Colors are created by layering ink; combining all four generally gives you a dense dark tone.
• Because it relies on ink rather than light, CMYK has a smaller color gamut—so some vibrant RGB colors can appear duller when printed.

When to use CMYK:
✔ Business cards
✔ Posters and flyers
✔ Packaging
✔ Magazines, brochures, and anything printed on paper

Why Converting Matters

If you design in RGB and send that file straight to print, the printer will convert your colors to CMYK automatically.
That can lead to:

• Unexpected color shifts
• Duller or less accurate tones
• Inconsistency between what you saw on your screen and the final print

By converting your document to CMYK before you start designing—or at least before exporting—you can catch and adjust these shifts early.

Pro Tip

Always check your printer’s specifications. Some want files delivered in CMYK PDF/X-1a or PDF/X-4; others may accept RGB for certain digital printing processes, but they’ll clarify that in their guidelines.

What is borderless printing?

Borderless printing simply means that the final document will be produced with the content reaching the edges of the media – instead of a white border running along the edge. It’s a favourable, popular choice for professional printing, but to achieve it, there’s some things you need to prepare.

Why You Need Trim Lines and a 3 mm Bleed for Borderless Printing

If you’re designing anything that goes right to the edge of the page—a full-bleed photo, a background colour, or graphics that run off the side—you’ll need to prepare your file with trim lines and bleed. These small additions make a big difference in achieving clean, professional results.

What Is a Trim Line?

The trim line (sometimes called the trim box) shows exactly where the finished product will be cut.
Printers trim stacks of paper in bulk, and even with precise equipment there’s always a tiny margin of movement. That’s why you never want important content sitting directly on the trim line.

Think of the trim line as the “final size boundary” of your design.

What Is Bleed?

Bleed is the extra area that extends beyond the trim line.
It ensures that when the printed sheet is trimmed down, any slight cutting variation doesn’t leave an unwanted white edge.

Your required bleed: 3 mm on all sides.

For example – if your final (trimmed) size is 210 × 297 mm (A4), then your document size with bleed should be:

• 216 × 303 mm total
  (That’s +3 mm on each side.)

Your artwork—photos, background colors, shapes—should extend all the way into this bleed area.

Keep important content inside the safe zone

Just as artwork should extend outside the trim line into the bleed, important elements like:

• Text
• Logos
• UI elements
• Anything you want clearly visible

should stay inside a safe zone, usually 3–5 mm inside the trim line, to avoid being cut too close.

How to Set Up a 3 mm Bleed

In Adobe Illustrator / InDesign

• Set bleed to 3 mm on all sides when creating your document.
• You’ll see a red line that marks the bleed area.

In Photoshop

• Manually increase canvas size by 6 mm (3 mm per side) for bleed.
• Add guides at the trim size to mark your final cut area.

When exporting

• Export as PDF with “Use Document Bleed Settings” enabled.

🎯 The Result

Proper bleeds + trim lines =
✔ Clean, borderless prints
✔ No unexpected white edges
✔ A polished, professional finish

File types

Now that we’ve conquered colour modes, trims and bleeds together, I want to show you the different file types you may encounter and what their best uses are. There are many after all, and it can be sometimes daunting about choosing the right output for the best results.

Quick summary

🏆 Best Choice: PDF (Print-Ready PDF/X)

Recommended for: almost all professional printing

Why it’s ideal:

• Preserves vector graphics (logos, text, line art) at full quality
• Embeds fonts and images
• Handles CMYK, spot colours, and transparency correctly
• Includes trim marks and bleed
• Universally accepted by commercial printers

Best settings:
✔ PDF/X-1a (flattened, CMYK) – super reliable for traditional print
✔ PDF/X-4 (supports transparency and modern workflows)
✔ Include 3 mm bleed + crop marks

When to use:
Any time you’re sending artwork to a print shop — business cards, brochures, posters, packaging, signage.

🧩 AI, INDD, PSD (Native Design Files)

Recommended for: sending to a designer, not directly to a printer

Native file formats from Illustrator, InDesign, or Photoshop are great for editing, but not ideal to hand directly to a print provider unless they specifically request them.

Pros:

• Fully editable layers
• Perfect for collaboration

Cons:

• Fonts may be missing
• Linked images may break
• Colour settings might not transfer

When to use:
Only if your printer or designer asks for them, usually as part of a project workflow — not for final print delivery.

🖼 High-Resolution JPEG

Recommended for: simple photographic prints and posters

Why it works:

• Great for images and photos
• Small file size
• Easy to handle

Limitations:

• JPEG is compressed, so repeated saving reduces quality
• Not ideal for vector graphics or small text
• Cannot contain transparency
• Doesn’t support spot colours

When to use:
Photo prints, basic posters, or large-format images where no detailed vector work is required. Always use 300 dpi minimum for print.

🌐 PNG

Recommended for: online use, NOT printing

Why PNG isn’t great for print:

• Limited to RGB
• Can’t handle CMYK
• Larger file sizes
• Not meant for high-resolution print output

When to use:
Web graphics, UI elements, transparency on digital content — not print.

📄 Microsoft Word / PowerPoint / Publisher Files

Recommended only when no design software is available

Printers can technically output these files, but they are highly unpredictable.

Issues:

• Fonts may reflow or substitute
• Colours are RGB only
• Layouts can shift depending on version or OS
• Limited bleed support

If you must use them:
Export to PDF before sending.

💎 TIFF

Recommended for: high-end image reproduction

Pros:

• Lossless quality (no compression artefacts)
• Supports CMYK and high bit-depth
• Excellent for photography or fine art printing

Cons:

• Very large file sizes
• No vector support

When to use:
High-quality image-based work — gallery prints, photo books, art reproduction.

🧭 EPS

Recommended for: vector graphics (sometimes)

EPS is an older format for vector artwork.

Pros:

• Good for logos, line art, technical drawings

Cons:

• Doesn’t handle transparency well
• Largely replaced by PDF
• Can produce unexpected results in modern workflows

When to use:
Only if a printer specifically requests EPS. Otherwise, PDF is safer.

Conclusion

Preparing your artwork correctly before sending it to print isn’t just a technical formality — it’s the key to getting crisp, accurate, professional-looking results. By choosing the right colour mode, adding trim lines and a proper 3 mm bleed, and exporting in the correct file format, you’re setting your project up to look exactly the way you intended.

A little extra care at the setup stage can save you from colour shifts, blurry edges, missing fonts, or costly reprints later on. Whether you’re designing a simple flyer or a full brochure, following these best practices ensures your final print comes out clean, sharp, and true to your vision.