Printing Inside the Lid of a Mailer Box

What is inside print on a mailer box?

A mailer box is cut and creased from one flat sheet of corrugated board. Printing the outside puts your artwork on the face the postie sees. Printing the inside puts it on the face your customer sees when the lid lifts.

The two surfaces are printed in separate passes, so you can treat them differently. Many brands keep the outside plain kraft and save the colour for the inside. Others print both faces in full, which is what our double sided printed mailer boxes are built for.

The inside of the lid is the first thing a customer reads. A short line of text there does more than the same line on the base, because the hands have not reached the product yet.

Where does the inside print sit on the flat net?

The flat net, or dieline, shows every panel of the box laid out before folding. The inside artwork is drawn on the reverse of that net. Three areas matter most.

• The lid: the large panel that folds over and shows first. Headline messages and the main pattern go here.
• The base: the floor of the box under the product. A pattern here frames the item once the tissue or insert is lifted out.
• The inner front: the roll-over panel the lid tucks behind. It shows as a strip under the lid and suits a small line or a repeat of the pattern.

The side walls and dust flaps are usually left plain or carry the same flat colour. Fine detail on them is wasted, because they fold tight against the product. On a tuck top mailer the front is double thickness, so the print on the inner layer faces inward and shows once the lid is lifted.

One colour on kraft or full colour on white-lined board

Brown kraft board takes one or two colours well. The ink sits on the natural brown fibres, so a dark red, navy or black reads as a clear mark. White ink on kraft looks soft and slightly textured, which suits handwritten-style text and simple line patterns.

Pale colours such as yellow or pink disappear into kraft unless a white underprint is laid down first. The underprint is a flat layer of white under the colour that gives it a clean base. It is a good option when you want a bright inside on a brown box.

White-lined board is coated on the print face, so full colour sits bright and even. Photographs, gradients and tight patterns need this board. The photos on our custom printed mailer boxes page show how a flat block of colour fills the inside without any patchiness.

What can you put inside the lid?

Inside print is not only decoration. Think of the lid as a panel the customer is certain to look at for a few seconds.

• A thank-you line, a greeting or a short message from the founder.
• A repeat pattern that carries the brand colour across the lid and base.
• Care or set-up instructions for the product, so the leaflet can be dropped.
• A line that asks for a photo, a review or a share, with a handle to tag.
• A discount code or a prompt to come back for the next order.
• A map of what sits where in a kit, printed on the base under each item.

Keep the wording short. One line in a large size reads better than a paragraph in small type. Text under 8 pt on corrugated board can fill in on kraft and is best avoided.

How does inside print change the unboxing?

A plain brown box that opens onto a full colour interior gives a small surprise. That contrast is why so many subscription brands print the inside and leave the outside quiet. The outside says little to the courier and the neighbour; the inside says everything to the customer.

The same trick works for gift sellers. A birthday or wedding order arrives looking like a parcel and opens like a present. For monthly orders, the inside can change each quarter while the outside stays the same, which is how our subscription box mailers are often run.

If customers film their unboxing, the lid is the panel the camera sees first. Put the message or pattern there rather than on the base.

How does the proof show inside print?

Every order gets a free design proof before anything is printed. For an inside printed box, that proof comes in two parts.

The first is the flat net with the outside artwork on one sheet and the inside artwork on a second. Each panel is labelled, so you can see which area becomes the lid, the base and the inner front. Bleed and creases are drawn as lines on top.

The second is a folded view that shows the box open, with the lid up and the base visible. This is where you check that the pattern reads the right way up when the lid lifts towards the customer. Nothing is printed until you approve both views.

Setting up the artwork

A few rules make inside artwork print cleanly the first time.

1. Work on the dieline we send, not a drawn guess. Each panel is already sized to the inside dimensions of your box.
2. Extend any background colour or pattern 3 mm past the edge of every panel. This is the bleed, and it stops a white sliver showing at the cut.
3. Keep text and logos at least 5 mm inside the crease lines. Creases crush the board slightly and a crease through a letter breaks it.
4. Never run fine text or a thin line across a crease from the lid onto the back wall. A bold pattern can cross a fold; small type cannot.
5. Check the orientation. The lid artwork should read the right way up to someone facing the open box, not to the person looking at the flat net.
6. Supply vector files for logos and text, and images at print size. Convert colours to CMYK, or name a single spot colour for a one colour job.

If your file is not ready, the Design Your Mailer Box page lets you place a logo on the lid and see it on the box before you send anything.

What does inside print add to the job?

Inside print adds a second printing pass, so the job costs more than an outside only box. How much more depends on the board, the number of colours and any finish, and the written quote shows it as its own line.

Board choice also changes the result. E-flute gives a smoother surface for fine pattern work, and our guide on E-flute and B-flute board explains that choice in more detail.

Ordering an inside printed mailer box

Tell us the inside size of the box, the board, and which faces you want printed. Say how many colours go on each face. If you have the files, attach them; if not, describe the idea and we will draw a first version.

We reply with a written quote within one working day. After you approve the proof, production takes 4 to 6 working days, and tracked UK mainland delivery is free and takes 2 to 3 working days.

Boxes arrive flat in bundles, with the printed inside facing in on the folded net. Fold one, open the lid and check the message reads as it did on the proof. Then request a written quote for the full run.