Artwork delays are the most common cause of packaging production timelines running over. Not material availability, not press capacity. Artwork. The box has been designed, samples approved, the order placed. Then the pre-press check comes back with problems, and you're looking at two to three weeks of revision before the job can go to plate.
Almost all of it is avoidable. Here's what needs to be in order before you send a print file to a packaging supplier.
Why starting without a confirmed dieline costs you two weeks minimum
Every printed packaging job begins with a dieline: the technical flat-layout template showing exact box dimensions, fold lines, cut lines and bleed area. The dieline is structural information from the packaging manufacturer, not something your designer creates.
Starting artwork development before you have a confirmed dieline is the single most common source of rework. Your designer works to approximate dimensions and creates artwork that doesn't fit the actual flat layout. When the confirmed dieline arrives, the artwork needs to be rebuilt.
Get the dieline first. This requires confirming your box style, dimensions and board grade with the supplier. If any of those change after artwork development starts, the artwork changes too. The dieline should be a vector file (PDF, AI or EPS) and locked on its own layer in the design file, never modified by the designer.
The colour and format errors that stop jobs at pre-press
Colour mode. Print is CMYK. Artwork designed or supplied in RGB will shift colours on conversion, sometimes subtly, sometimes considerably. Blues are particularly prone to shifting. Design in CMYK from the start, not as an export step at the end.
Pantone colours. If your brand uses a specific Pantone (spot) colour, confirm with your supplier whether their print process can match it. Flexographic printers can usually accommodate spot colours. Digital press operations typically convert everything to CMYK, which means your Pantone 485 red becomes a CMYK approximation. If an exact Pantone match is required, specify it by reference number in the brief.
File format. PDF/X-1a or PDF/X-4 are standard for press-ready files. Packaged InDesign or Illustrator files are usually acceptable. Never supply PSDs or Word documents.
Image resolution. Any photographic or rasterised element needs to be 300dpi at the final printed size. 72dpi screen-resolution images look sharp on screen and print soft. Easy to check before submission; impossible to fix without redesign.
Bleed, safe zones and barcodes: where jobs get rejected
Bleed is the artwork extension beyond the cut line, typically 3mm for corrugated packaging. It exists because cutting isn't perfectly precise: without bleed, small misregistrations produce a white edge. All background colours and images extending to an edge must extend into the bleed area.
Safe zone is the margin inset from the cut line within which all critical content should sit: text, logos, barcodes, legal information. Minimum 5mm from the cut line for most corrugated applications.
Barcodes cause persistent pre-press problems. The most common failures: the barcode is too small (GS1 minimum sizes for EAN-13 and ITF-14 codes must be met for reliable scanning), the colour combination won't scan reliably (supply as black bars on white background unless the substrate forces otherwise), or the barcode data itself is incorrect. If your barcode was generated in-house, run it through a verification check before submitting. A barcode error that gets through to printed stock creates a retail listing problem that's expensive and disruptive to fix.
The content check suppliers cannot do for you
Pre-press checks catch technical file problems. They don't catch incorrect content. Before submitting, verify: the product name is spelled correctly, weight or volume declarations are accurate and legally compliant, all required regulatory text is present (recycling logos, legal manufacturer details, allergen information if applicable), contact details are current, and any legally controlled claims have been approved.
Discovering a content error after printing costs more than checking before submission. Always.