Inside print is the line item that marketing teams want and operations teams question. Printed outside, a mailer is seen by the courier, the neighbour and the customer for a few seconds on the doorstep. Printed inside, it is seen at the moment the customer opens the lid, which is the moment most likely to be photographed and shared. For a volume buyer, inside printed mailer boxes usually earn their extra cost where the opening is part of the product (subscriptions, gifting, cosmetics, campaigns) and rarely on replenishment or multi-item orders.
The extra cost comes mainly from a second print pass and, for bright colours, a white inner liner. The sections below cover how interior print is produced, what drives the price, how to design for the panels the customer actually sees, and cheaper ways to get a similar effect. For construction, board and outside print, see our main page on custom printed mailer boxes.
How is the inside of a mailer box printed?
The inside of a mailer is the reverse face of the same flat sheet, so printing it means printing the board on both sides. Depending on the process, that takes a second pass through the press, a press that prints both faces, or a separately printed inner liner before the board is made. Each route adds cost and process steps.
| Print method | How inside print is done | Practical implications |
|---|---|---|
| Flexo post-print | Board is printed on one face, then turned and printed on the other, or run on equipment able to print both faces | Second set of plates and set-up; risk of marking the first side; registration between faces must be managed on the dieline |
| Litho-lam (outside) with flexo or digital inside | Outside is an offset-printed sheet laminated to the board; inside is printed on the inner liner by another process | Two processes with different colour behaviour; inside usually simpler artwork |
| Pre-print | The inner liner reel is printed before corrugating | Economical only at large, stable volumes; artwork committed early |
| Digital inkjet | Both faces printed digitally, in two passes | No plates; good for short runs and versions; ink cost per box rises with coverage |
Because the inside face of a standard board is usually a brown testliner, bright interior colours generally need a white inner liner. Upgrading the inner liner is often a larger cost than the ink itself.
What makes inside print expensive?
Inside print cost is driven mainly by the extra print pass and set-up, the inner liner upgrade if colours must look bright, and ink coverage. A single dark colour on brown kraft inside is the cheapest option; full-bleed colour on a white inner liner is the most expensive.
Main cost drivers, roughly in order of impact:
- An extra print pass or process: plates or set-up for the second face, plus press time and waste.
- Inner liner colour: a white inside liner instead of brown testliner, for bright or light colours.
- Coverage: flood coats of colour use far more ink than a logo or line pattern, and on flexo they show board defects more readily.
- Number of colours: each additional flexo colour adds a plate and a print unit.
- Registration demands: artwork that must align precisely with folds or panel edges reduces acceptable tolerance and increases waste.
The overall effect on unit price depends on run length and specification and is confirmed at quotation. For how print set-up costs are spread over a run, see packaging cost drivers.
When are inside printed mailer boxes worth it?
Inside print tends to pay back where the opening moment is part of the product: subscription boxes, gifting, beauty and cosmetics, limited editions, and launch campaigns that rely on customers posting unboxing content. It is harder to justify for replenishment orders, multi-item fulfilment boxes, or products whose own retail packaging is the hero.
A useful test is to ask what the customer sees when the lid opens. If the product sits in its own printed carton or tissue that covers the interior, most of the inside print will never be seen. If the product sits directly in the box or on an insert, the lid panel and the front wall get attention.
Design rules for printing inside a mailer
Interior artwork is designed on the dieline, not on a picture of the finished box, because the visible panels when the lid opens are not the ones a mock-up suggests.
- Prioritise the inside of the lid. It faces the customer when the box opens and is the panel most often photographed.
- Use the inner front wall and tuck flap for short messages; they are seen as the lid lifts.
- Keep critical content off rolled side walls and dust flaps, which fold over each other and break up artwork.
- Leave glue, adhesive and tear-strip zones unprinted where the converter requires it, and keep text clear of creases.
- Design for reading orientation when the box is opened from the front, not as the sheet lies on the press.
- On kraft, choose dark colours or use an opaque white; light pastel colours disappear on brown.
- Pattern repeats tolerate registration variation better than a single large graphic that must line up across panels.
For artwork file set-up, bleed and dieline layers, see our packaging artwork guide. For matching brand colours on brown and white board, see Pantone vs CMYK for packaging.
Cheaper ways to create an unboxing moment
Several alternatives deliver much of the effect of full interior print for less, and can be changed more easily:
| Option | Effect | Cost and flexibility |
|---|---|---|
| One-colour inside print, lid only | Message or pattern where the customer looks first | Single plate; lowest-cost inside print |
| Printed insert card | Thank-you note, care instructions, offer code | Separate small print job; easy to change by campaign |
| Printed corrugated insert | Holds the product and carries the brand | Replaces void fill; doubles as protection |
| Printed tape or sticker seal | Branded first touch | Low cost; adds a packing step |
| Digital short runs for campaigns | Seasonal or limited-edition interiors | No plates; higher unit cost but low commitment |
A common pattern among volume brands is a flexo-printed standard mailer for everyday orders, with a short digitally printed run for campaigns or VIP customers. Another route is a plainer mailer with branded tissue paper and thank you cards for packages inside, which move the brand content onto separate printed items.
Recyclability and the PPWR
Inside print with water-based inks does not normally stop a corrugated mailer from being recycled with paper and board. What can complicate recyclability is the decoration added around it: full plastic film lamination, foil, heavy varnishes, foam inserts or plastic windows. Under the EU PPWR, Regulation (EU) 2025/40, packaging must meet recyclability performance grade A, B or C from 1 January 2030, and the minimisation requirement from 2030 discourages extra layers that add no function.
The PPWR also limits empty space in e-commerce packaging to 50 % for the operator who fills it, from 2030 at the earliest. Tissue and paper fill used for presentation count as empty space under that rule, which is another reason to put brand content on the box and insert rather than in loose fill. See e-commerce packaging and the PPWR.
Proofing and approval for two-sided print
Two-sided jobs need more careful approval than outside-only print:
- Approve a dieline proof showing both faces, with the inside mirrored correctly relative to the outside.
- Ask for a folded white sample or digital prototype to check what is visible when the lid opens.
- Agree colour targets separately for each face if different processes or liners are used.
- Check that no inside content falls under a tear strip, adhesive strip or insert.
Quality checks during production are covered in packaging quality control.
What to send when asking for inside print
- Outside and inside artwork on the supplier's dieline, or a brief if the dieline is not yet made.
- Number of colours inside and outside, Pantone references and coverage.
- Inner liner preference: brown or white.
- Whether inside print applies to all sizes or only some.
- Quantities per size and whether campaign versions are expected.
Send these with your size range through the custom printed mailer boxes page, and we will review the print route and liner options before quoting.