How to Prepare Artwork for Custom Packaging

One of the most common causes of production delays is artwork that is not print-ready. Files arrive in the wrong format, at the wrong resolution, with fonts not outlined, or without proper bleed. The result is days of back-and-forth between the brand, the designer, and the supplier before a single box gets made.

Here is what you actually need to prepare and how to get it right the first time.

Step 1 — Get the Dieline First

A dieline is a flat, technical template showing the exact shape and fold lines of your packaging. Every box style has its own dieline — a tuck-end carton looks completely different laid flat than a mailer box or a rigid box lid.

Do not start designing until you have the correct dieline. Designing on a generic template and then trying to adapt it to the actual structure almost always results in misaligned artwork.

At UPG, dielines are provided as part of the quoting process for your specific dimensions. If you are working with a designer, share the dieline file (usually an Adobe Illustrator .ai or .eps format) with them before design work begins.

Step 2 — Set Up Your File Correctly

When your designer opens the dieline, they should set up the artwork with these specs:

• Format: Adobe Illustrator (.ai) or print-ready PDF. Photoshop files are rarely accepted for final print.
• Color mode: CMYK, not RGB. RGB is for screens. Printing is CMYK. Colors will shift significantly if you send an RGB file.
• Resolution: 300 DPI minimum for any raster images (photos, textures). Vector elements (logos, text) are resolution-independent.
• Bleed: Typically 0.125 inches (3mm) beyond the dieline edge. Bleed prevents white edges appearing on the printed piece if the cut shifts slightly.
• Safe zone: Keep important text and logos at least 0.125 inches inside the dieline edge.
• Fonts: Outline all fonts before saving the final file. This converts text to vector shapes so the printer does not need your exact font installed.

Step 3 — Check Your Colors

If brand color accuracy matters — a specific Pantone red, a precise navy blue — specify your PMS (Pantone Matching System) colors in addition to CMYK values. CMYK printing has a limited gamut and cannot reproduce every Pantone color exactly.

For packaging printed in full color (process printing), CMYK is sufficient. For spot colors where precision matters, request PMS color matching and confirm with the supplier whether it is supported for your run size.

Step 4 — Submit with a Mockup

Along with the print-ready file, include a 3D mockup or a visual reference showing what the finished packaging should look like. This gives the production team a reference point if they have any questions about intent.

If you do not have 3D mockup software, even a PDF showing each panel of your design labeled (front, back, left, right, top, bottom) works as a clear reference.

The Short Version

• Get the dieline before designing
• Work in CMYK at 300 DPI
• Include 3mm bleed on all edges
• Outline all fonts
• Submit as .ai or print-ready PDF

If you have artwork in progress but are not sure whether it is ready, include it with your quote request and note its status. We review artwork as part of the quoting process and will flag any issues before production begins.