Print-ready packaging files explained: a checklist for designers

A packaging design can be beautiful on screen and still fail at the printer. A missing bleed, an RGB image, a font that substitutes, or a foil layer that does not line up can delay production, cause reprints or ruin a launch. "Print-ready" means a file that a printer can take straight to press with no corrections. This guide explains what that involves for boxes, labels and pouches, and ends with a pre-flight checklist you can use on every job.

What "print-ready" means

A print-ready packaging file is one that:

• is built on the correct dieline for the exact box, label or pouch
• has the right bleed, safe areas and orientation
• uses the correct colour mode and spot colours
• has high-resolution images at the final size
• has fonts embedded or outlined
• has finish layers such as foil and spot UV set up separately
• has accurate, proofread text, including mandatory information and barcodes
• is exported in the format your printer specifies

Every printer has its own specifications. Before starting artwork, ask for them, along with the dieline. The rest of this guide covers the points that apply almost everywhere.

1. Start with the right dieline

The dieline is the foundation. It must come from your printer or manufacturer, for the exact structure, size and material. A dieline for a 400 gsm carton is different from one for E-flute board or a rigid box wrap, even at the same internal size. Our dieline guide explains this in detail.

Set it up correctly:

• Place the dieline on its own locked layer.
• Use a spot colour for the dieline, named clearly, such as "Dieline", and set to overprint or non-printing as your printer requires.
• Keep it at 100% scale. Never resize a dieline.

2. Bleed, safe area and orientation

Bleed

Extend any artwork that touches a cut edge beyond the cut line, typically by 3 mm. Cutting is never perfectly exact, and bleed prevents thin white edges. Some processes or printers ask for more.

Safe area

Keep important text, logos and barcodes inside the safe area, usually at least 3 mm from cut and fold lines. Folds can crack ink and shift alignment slightly.

Orientation

On a flat dieline, some panels are upside down or rotated relative to how they will be seen. Lids, tuck flaps and bottoms are common mistakes. Print a paper proof, cut it out and fold it to check.

Glue areas

Leave glue flaps and glue zones free of ink and coatings unless your printer says otherwise. Ink and varnish can stop adhesive bonding.

3. Colour

Colour mode

Set up artwork in CMYK for process printing, plus any spot colours such as Pantone references. Do not send RGB files unless your printer specifically asks for them. RGB colours shift, sometimes dramatically, when converted to CMYK.

Spot colours

Name spot colours exactly as your printer expects, and make sure there are no duplicate or unused spot colours in the file. A single brand colour defined three different ways can produce three plates.

Rich black

For large black areas, a rich black (black plus some cyan, magenta or yellow) looks deeper than black alone. For small text, use 100% black only, to avoid registration problems. Ask your printer for their preferred rich black values.

Total ink coverage

Too much ink in one area can cause drying problems, set-off and poor finishing. Printers often set a maximum total ink coverage. Check your darkest areas.

Colour on different substrates

The same CMYK values look different on coated white board, uncoated board and kraft. Our guide to Pantone vs CMYK explains how to handle this.

4. Images

• Use images at around 300 ppi at final printed size for most offset printing. Lower resolutions can work for coarser processes, but ask first.
• Convert or prepare images in the correct colour profile for the print process.
• Link or embed images as your printer requires, and include all linked files if you send native files.
• Avoid upscaling low-resolution images. It does not add detail.

5. Fonts and text

Fonts

Either embed fonts in the PDF or convert text to outlines. Outlining prevents font substitution but makes later edits harder, so keep an editable master with live text.

Minimum sizes

Small text can fill in or break up, especially on uncoated or textured materials, flexible films and corrugated board. Check minimum text sizes and line weights with your printer. Fine lines and small reversed text, such as white text on a dark background, are especially risky.

Mandatory text

Ingredient lists, nutrition panels, warnings, net quantity and addresses must be accurate and meet legal minimum sizes. Copy them from approved sources, not from old labels, and proofread line by line.

Barcodes

Use barcode artwork generated by reliable software at the correct magnification, with clear quiet zones and good contrast. Do not stretch, compress or redraw barcodes. See our barcode guide for detail.

6. Finish layers

Finishes such as foil stamping, spot UV, embossing, debossing, white ink and varnish each need their own setup:

• Create each finish as a separate spot colour or layer, named clearly, such as "Foil_Gold" or "SpotUV".
• Set finish layers to overprint so they do not knock out the artwork beneath, unless your printer says otherwise.
• Use 100% solid values for finish layers; no tints or gradients unless the process supports them.
• Align finishes exactly with the artwork they relate to.
• Check minimum line widths and gaps for foil and embossing; fine details can fill in.
• Keep foil and embossing away from folds and edges where they may crack.

White ink

For clear labels, metallic films and kraft board, a white underprint behind colours keeps them bright. Set it up as a separate spot layer and check which elements need it.

7. Export

Most printers prefer a press-ready PDF, often in a PDF/X standard, which embeds fonts and colour information in a reliable way. Check:

• the PDF standard required
• whether to include crop marks, bleed marks and colour bars
• whether the dieline and finish layers should be in the same file or separate files
• the file naming convention

If you send native files, package them with all fonts and linked images.

8. Proofing

Digital proofs

Your printer will usually send a digital proof showing the artwork on the dieline. Check every panel, every word and every finish layer. This is your last chance to catch errors cheaply.

Colour proofs

For new packaging, ask for a colour proof and a 3D mockup. A colour proof shows how colours print, and the mockup shows how finishes and folds come together.

Approval

When you approve a proof, you are usually confirming that the content and layout are correct. Errors you approve may become your cost to fix. Take approval seriously and involve everyone who needs to check content.

Pre-flight checklist

Use this before sending any packaging file to print:

Dieline

• Correct dieline from the printer, at 100% scale
• Dieline on its own layer, as a named spot colour, non-printing or overprint

Layout

• Bleed extended at least 3 mm (or as specified)
• Text, logos and barcodes inside the safe area
• Panels checked for orientation on a folded paper proof
• Glue areas clear

Colour

• CMYK plus named spot colours only; no RGB
• No duplicate or unused spot colours
• Small text in 100% black
• Total ink coverage within limits

Images

• About 300 ppi at final size, or as specified
• Correct colour profile
• All links included or embedded

Text

• Fonts embedded or outlined, with an editable master saved
• Minimum text sizes and line weights checked
• Mandatory text copied from approved sources and proofread
• Barcode correct, at the right size, with quiet zones

Finishes

• Each finish on its own named spot layer, set to overprint
• Finishes aligned with artwork
• Minimum line widths for foil and embossing
• Finishes away from folds and edges
• White underprint set where needed

Export

• Correct PDF standard and marks
• Files named as the printer asks

How we help

We design packaging and prepare print-ready files for our own factory and for other printers. Because we print rigid and printed boxes ourselves, our files are built for real machines, real dielines and real finishes, and we check them on a digital proof before production. See also the most common packaging design mistakes and how to avoid them.

See our box packaging design and label design services, or get a free quote for your artwork and production.

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Questions

What file format do printers want for packaging?

Usually a press-ready PDF, often PDF/X, built on the printer's dieline. Many also accept the native Illustrator file with fonts outlined and images linked.

How much bleed does packaging need?

Typically 3 mm beyond the cut line, but some printers and processes ask for more. Always follow your printer's specification.

What resolution should images be?

Around 300 ppi at the final printed size for most offset printing. Lower can work for large-format or coarse substrates; ask your printer.

Should I outline fonts?

Outlining or embedding fonts prevents substitution. Keep an editable version with live text for future changes.

What is a pre-flight check?

A systematic check of the file before it goes to press, covering dieline, bleed, colour, resolution, fonts, finishes and text, often supported by software.

Who is responsible for errors in print files?

Usually whoever approves the proof. That is why careful proof review, at actual size and on the real dieline, matters.