Artwork and Dieline File Preparation: A Buyer's Checklist

Artwork is the first hand-off in any packaging project, and it is where most avoidable delays start. A file that looks fine on screen can still be unusable for production if the dieline is missing, the colour space is wrong, or the bleed is too small. This checklist covers what buyers should prepare before sending files to a supplier.

Why artwork preparation decides your schedule

Printers work from files, not from intentions. When a file is missing a dieline or uses RGB images, the supplier has to stop and ask questions, and every round of clarification adds days to the schedule. Preparing files properly is usually faster than fixing them later.

What a dieline contains

A dieline is the technical drawing of a packaging shape. It normally includes:

• Outer cut lines that define the finished outline
• Crease or fold lines, shown as dashed lines
• Glue flaps and tuck-in areas
• Registration marks and a job reference
• Sometimes a separate layer for the printed face

Ask for the dieline in a vector format and keep the printed artwork on a separate layer, so the printer can hide or show lines as needed.

File formats and colour settings

Vector versus raster

• Supply logos, text and line art as vector paths (PDF, AI or EPS) so they stay sharp at any size.
• Keep photographic images as embedded or high-resolution linked files.
• Avoid editing files in bitmap tools after the final proof is approved.

Colour space

• Convert images to CMYK before sending files for process printing.
• Specify brand colours as a spot ink, for example a Pantone reference, when the colour must stay consistent across reprints.
• Ask the supplier which colour reference they will match against, and agree the viewing conditions for approval.

Image resolution

• Use images at 300 dpi at final printed size, or higher if the printer requests it.
• Check that image files are not upscaled, which shows as softness in print.

Bleed, safety margin and folding

• Add bleed on every trimmed edge. 3 mm is a common starting point, and larger formats sometimes need more.
• Keep text and logos inside a safety margin of around 3 to 5 mm from trims and creases.
• Avoid thin lines and small type across creases, where cracking is more likely.
• For heavy ink coverage over folds, ask the supplier about creasing and scoring options.

Barcodes, legal text and language panels

• Leave the quiet zone around barcodes clear and confirm the minimum barcode size with the retailer.
• Check that required legal, ingredient or recycling text fits inside the panel, not across a fold.
• Agree which language versions are needed and whether they are printed on the same panel or as separate versions.
• Legal and labelling requirements differ by destination market, so confirm the wording with your own compliance advisor.

A pre-send checklist

• Dieline included as a separate layer, with cut and crease lines clearly marked
• Bleed and safety margins applied
• All images at print resolution and in CMYK
• Spot colours named and matched to a reference
• Fonts embedded or outlined
• Overprint settings reviewed for dark text on dark backgrounds
• File exported as a single print-ready PDF at the agreed version
• Page order and version number in the file name
• Contact details included in case the printer has questions

Common reasons files are rejected

• RGB or low-resolution images left in the layout
• Missing bleed, or bleed applied but not used
• Text placed over a crease or inside the trim
• Spot colour and process build mixed on the same element
• Several versions of the same file with no clear version label

Most suppliers will produce a physical or digital proof before the main run. Review that proof carefully, keep the approved version as a reference, and refer to it when later reprints are ordered.

Key figures and tolerances

• Bleed: 3 mm on cartons, 5 mm on rigid boxes; keep type and logos 3 mm or more inside the trim.
• Raster resolution: 300 dpi at final size; keep lines and type as vector.
• Minimum type size: 5–6 pt positive, 6–7 pt reversed out.
• Trap: 0.1–0.2 mm to cover misregister.
• Total ink coverage: 300–320% maximum on coated, 240–260% on uncoated or recycled board.
• Colour target: ΔE 2.0 or better at press under ISO 13655, with offset process control to ISO 12647-2.
• Ranges are typical industry values for the material or process named and are not a specification; confirm the exact value, the current edition of each standard and the applicable grade with your supplier or test laboratory.