How to Prepare Artwork for Mailer Printing

Most artwork problems in packaging are sequencing problems rather than design problems. The file is fine; it was simply made before a decision that constrains it.

Getting the order right removes almost every reason for a second proof round, and it costs nothing.

Four decisions that come before design

Each of these constrains the artwork. Making them afterwards means redrawing rather than adjusting, so settle them alongside the rest of the decisions that belong before a quotation.

Size, settled on a physical sample. Artwork is laid out for a specific panel. If the size changes, the layout changes, and a design approved for a 10x13 does not simply scale onto a 12x15 — the proportions of the printable area are different once the flap and welds are accounted for.

Base colour. The film colour decides which inks will read on it. A dark mark cannot go on a dark base, white barely reads on blush, and a mid-grey disappears against almost anything. Discovering this at proof stage costs a week for no reason.

Finish. Matte and gloss change how the same ink reads to a noticeable degree. Approving artwork before the finish is chosen means approving it twice.

Coverage. Logo, partial or full, and one side or two. This is the budget conversation, and it belongs before a designer starts rather than after they have produced something that cannot be afforded.

Designing for a bag rather than a page

By the time anyone sees your artwork, the mailer has been packed, folded at the flap, sealed, labelled, stacked and carried. Designs that ignore that arrive looking wrong even when they printed perfectly. Placing a mark on a mailer outline is a quick way to see where the folds fall before drawing anything.

Four rules cover most of it.

• Keep the important elements clear of the flap. The top band folds over and is sealed. Anything placed there is invisible on a packed parcel, and it is a surprisingly common mistake.
• Keep clear of the side welds. The edges are sealed and pinched, so artwork running into them distorts.
• Design a deliberate zone for the shipping label. A standard label covers a substantial share of a mid-size front panel and it goes wherever the packer finds space. Either leave a clear area sized for it, or put the design on the reverse and keep the front plain.
• Design for the packed shape, not the flat one. A composition that fills a flat template stretches once there is something inside. Centred marks with breathing room survive packing; tight edge-to-edge compositions do not.

Building the file

With the constraints settled, the file itself is straightforward. Six things to get right while designing rather than fix afterwards — the printing and artwork reference has the same list as a table to work against.

1. Work at final size. Design at the dimensions the bag will actually be, so type sizes and line weights are judged at real scale rather than scaled up at the end.
2. Mark the dead zones on your template. Draw the flap area and the weld margins and keep anything important out of both. Doing this visually beats remembering it.
3. Add bleed on every edge the artwork reaches. At least 3 mm. Film moves fractionally during production, and without bleed some proportion of the run gets an uneven white sliver.
4. Set colour deliberately. CMYK or a named spot colour rather than RGB. An RGB file has to be converted, and the conversion is where unexpected colour shifts come from — better that you see it than that we make the decision for you.
5. Outline the fonts. Live fonts substitute silently if the exact version is not available, and the substitution is usually invisible until the run is printed.
6. Increase line weights beyond what feels necessary. Fine lines close up on flexible film in a way they never do on paper. If an element looks slightly heavy on a flat proof, it is probably right on the bag.

What the surface does to your design

Everything above assumes flat film. Two other surfaces behave differently enough to need separate treatment.

A cushioned surface is a field of raised domes with valleys between them, and ink lands on both. Fine lines cross the texture and read as dotted. Small type loses its counters. Large areas of solid colour reveal the dimple pattern as highlights and shadows, which looks like inconsistent printing even when it is not. Designs for this format need heavier weights and simpler shapes rather than a rescale.

Translucent frosted film reduces contrast, because whatever is inside the bag shows through and affects how the ink reads. Dark inks hold their edge; white ink looks crisp or washed out depending on the contents, which makes it a risk when contents vary.

The practical rule is that a file works on the surface it was drawn for. Moving it to another means revisiting it rather than reusing it, and the differences are set out on the printed format comparison.

Using the proof properly

A proof is not a formality to click through. It is the last point at which anything can change without cost, and it becomes the document the finished run is checked against.

Check the things only you can check. Spelling. Your web address. Your social handles. Whether the mark is the current version rather than the one from two years ago. We have no way to know any of those are wrong, and once approved they are what gets printed.

Then check placement against a packed bag rather than a flat one. Ask where the label will land. Ask what happens to the design when the flap folds. Ask for the artwork at real size on paper if it helps — it usually does, and it catches problems that no amount of on-screen review will.

Ask for as many rounds as you need. A proof round costs a fraction of a reprint, and a supplier discouraging additional rounds is optimising their own process rather than your outcome.

What a proof will not reliably tell you is colour. A screen is backlit, film is not, and a colour that looks correct on a calibrated monitor can arrive materially different. Where a colour matters commercially — a brand colour customers recognise — ask for a physical check rather than approving digitally.

Rights, which are easy to forget

Before sending artwork, confirm you actually hold the commercial reproduction rights to everything in it.

Stock illustration bought on a personal licence, an image found online, and a design a freelancer was paid to produce are three different legal positions, and only one of them is safe to print at volume. Fonts carry licences too, and some restrict use in a logo or in packaging specifically.

This is not a hypothetical concern. Packaging is highly visible, produced in quantity, and easy to trace back — it is a poor place to find out about a licensing problem. What you confirm when you send us a file is set out in the custom order policy.

A short pre-flight list

Before sending a file, check all of these. It takes two minutes and prevents most of the correspondence that follows a first submission.

• Vector, or raster at 300 ppi at final size
• CMYK or a named spot colour, not RGB
• Bleed on every edge the artwork reaches
• Fonts outlined
• Nothing important in the flap or weld zones
• A clear zone for the shipping label
• Line weights heavier than feel necessary
• Spelling, web address and handles checked by someone other than the designer

If all eight are true, the file goes straight to proof. If any is not, it comes back — which costs a day, and is the entire reason this list exists. The full technical specification is on the artwork guidelines page.