Reference guide
Preparing Artwork for Mailer Printing
This is the walkthrough. It assumes you have not produced packaging artwork before and takes the whole thing in order, from the decisions that come before anyone opens a design application to the moment a proof is approved.
If you already know the process and just need the file specification — formats, bleed, resolution, colour mode — that is a separate page and it is shorter.
Before anyone opens a design application
Four decisions that constrain the design. Making them afterwards means redrawing.
Settle the size on a physical sample
Artwork is laid out for a specific panel. A size change after approval is a redraw, not an adjustment.
Choose the base colour
The base decides which inks will read. A dark mark cannot go on a dark film, and finding that out at proof stage wastes a week.
Choose the finish
Matte and gloss change how the same ink reads. Approving artwork before the finish is set means approving it twice.
Decide the coverage
Logo, partial or full. This is the budget conversation, and it belongs before the design rather than after it.
Building the file
Six things to get right while designing, rather than fixing afterwards.
Work at final size
Design at the dimensions the bag will actually be, so type and line weights are judged at real scale.
Mark the dead zones
Draw the flap area and the side welds onto your template and keep anything important out of both.
Draw the label zone in
Decide where the shipping label goes and leave that area clear. This is the most commonly skipped step.
Add bleed on any edge the artwork reaches
At least 3 mm. Without it, part of the run comes out with an uneven white edge.
Set colour deliberately
CMYK or a named spot colour, not RGB. An RGB file will be converted, and the conversion is where surprises come from.
Outline the fonts
Live fonts substitute silently. Outlining removes an entire class of problem.
Design decisions that survive a supply chain
A mailer is packed, folded, sealed, labelled, stacked and carried before anyone sees your design. These choices survive that.
Fewer elements, larger
One idea at generous scale reads across a warehouse. A dense composition reads at arm’s length and nowhere else.
Strong contrast over subtle palettes
Tonal designs that look sophisticated on screen turn to mush on film under fluorescent light.
Heavier line weights than feel necessary
Fine lines close up on flexible film. If it looks slightly heavy flat, it is probably right printed.
A centred composition with breathing room
Edge-to-edge designs distort once there is something in the bag. Centred ones survive packing.
The brand mark somewhere it will not be covered
Work out where the label lands before you decide where the logo goes, not after.
The proof stage, and how to use it properly
A proof is not a formality to click through. It is the last point at which anything can change without cost, and the document the finished run will be 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 cannot know any of those are wrong.
Then check placement against a packed bag rather than a flat one in your head. Ask where the label will go. Ask what happens to the design when the flap folds over. Ask for as many rounds as you need — a proof round costs a fraction of a reprint.
What a proof will not tell you reliably is colour. A screen is backlit and film is not. Where a colour is commercially important, ask for a physical check rather than approving on a monitor.
Different surfaces, different rules
Everything above assumes flat film. A cushioned surface breaks up fine lines and closes small type, and translucent frosted film reduces contrast because whatever is inside shows through. A file that works on one will usually need heavier weights and simpler shapes on another rather than a straight rescale. The differences between the printable surfaces are set out on the printed format comparison.
Questions about the printing and artwork guide
What should I decide before designing packaging artwork?
Size, base colour, finish and coverage — in that order. Each one constrains the design, and settling them afterwards means redrawing the file rather than adjusting it.
How do I know if my logo will print well on a mailer?
Print it at the exact size it will appear on the bag, on paper, and look at it from arm’s length. If any element becomes hard to read, it will be worse on film, and worse again on a cushioned surface.
How many proof rounds should I expect?
As many as you need. A proof round is inexpensive; a reprint is not. Suppliers who discourage additional rounds are optimising their own process rather than your outcome.
Can I approve colour from a digital proof?
For placement and scale, yes. For colour, only approximately — a screen is backlit and film is not. If a colour is commercially important, ask for a physical check instead.