The Plaid Studio / What to create / Mugs, boxes and notebooks
Pattern sizes for mugs, boxes and notebooks
A seamless pattern is not only for cloth. The same tile goes on a mug wrap, a box, a notebook cover, wrapping paper and a tin — and each of those is a rectangle with a real size, so the pixel count is one multiplication. Here is the geometry per surface, and the sum done for you.
The shape of each surface
Only one of these is a rectangle you can measure directly. The rest have to be opened out first, and that is where most files come back wrong:
| Surface | Artwork size | What the formula leaves out |
|---|---|---|
| A mug | π × diameter × height | A mug is a cylinder, so the artwork is its circumference by its height. Measure the diameter and multiply by 3.1416. Two things the geometry does not tell you: most printers leave a gap where the handle is, so the wrap is not a full circle, and the pattern has to work cut off at top and bottom. |
| A box or a tin | 2 × (width + depth) × height | For a band round the four sides. A full net -- lid, base and flaps as one flat shape -- is the manufacturer's drawing, not a formula; ask for the die line. Every fold wants the pattern to continue across it, which is what a seamless repeat is for. |
| A notebook or journal | 2 × cover width + spine × cover height | Front, spine and back are usually printed as one piece. The spine is the book's thickness; on a case-bound book add the hinge and the turn-in, which again is the binder's number. |
| Wrapping paper | roll width × any length | The width is fixed by the roll and the length is not, so a repeat that divides into the width cleanly is worth choosing. This is the one surface where a large repeat is an advantage rather than a risk. |
| A phone case or a tag | the template, exactly | Small, curved and cropped hard. Take the template and treat the whole edge as bleed; a repeat over about 4 cm will show as two or three motifs and read as a crop rather than a pattern. |
| A tote or a pouch | print area, from the template | Printed flat on one face, so it is a rectangle -- but the seams eat the edges and a bag folds in use, so keep anything you want read away from the sides. |
Take the exact figures from your printer's template. A mug wrap, a box net and a notebook's turn-in are the manufacturer's numbers, not the world's, and two mugs sold as the same size are not the same wrap. The arithmetic on this page does not change; theirs does.
Paper, at the sizes that are actually standard
ISO 216 is a standard rather than a supplier's choice, so these are safe to work from — and a notebook cover printed in one piece is two of them plus the spine:
| Size | Trimmed | At 150 dpi | At 300 dpi |
|---|---|---|---|
| A6 | 10.5 × 14.8 cm | 620 × 874 px | 1,240 × 1,748 px |
| A5 | 14.8 × 21 cm | 874 × 1,240 px | 1,748 × 2,480 px |
| A4 | 21 × 29.7 cm | 1,240 × 1,754 px | 2,480 × 3,508 px |
| A3 | 29.7 × 42 cm | 1,754 × 2,480 px | 3,508 × 4,961 px |
| A2 | 42 × 59.4 cm | 2,480 × 3,508 px | 4,961 × 7,016 px |
Pixels are inches times dpi, and inches are centimetres over 2.54 — that is the whole sum. A4 at 300 dpi is 2,480 by 3,508 pixels, and a 3 mm bleed on each edge adds 71.
Scale is the decision, not size
The tile is printed over and over, so it does not have to fit the product. What it has to do is read at that size. Three things worth settling before export:
- How many times should the repeat appear? On a mug wrap of 23 cm, an 8 cm repeat lands just under three times, which reads as a pattern. A 20 cm repeat lands once and reads as a picture that got cut.
- What survives the crop? A mug has a handle gap, a box has folds, a tote has seams. A small, evenly scattered repeat forgives all three; one big motif does not.
- How close will it be held? Paper in the hand wants 300 dpi. Cloth at arm's length generally gets away with 150 — the DPI guide has that argument in full, and the fabric sizes page does the same sum per fabric product.
Where the file stops being possible
Two limits are worth knowing before you promise a client a resolution. A browser stops encoding a PNG at about 8,192 pixels on a side, which is a surface of roughly 69 cm at 300 dpi or 138 cm at 150 — the calculator above turns red when you cross it. And a seamless tile has to be a whole number of pixels, or the joins land half a pixel out and show as a faint grid at print size. Set the repeat in centimetres and let the export work the pixels out.
Questions
What size should a pattern be for a mug?
As big as the mug's wrap: circumference by height. Measure the diameter, multiply by 3.1416 for the circumference, then convert to pixels at your printer's dpi — at 300 dpi a 23 by 9.5 cm wrap is 2,717 by 1,122 pixels. Take the exact wrap from your printer's template, because it usually leaves a gap at the handle.
How many pixels is A5 at 300 dpi?
A5 is 14.8 by 21 cm, which is 1,748 by 2,480 pixels at 300 dpi and 874 by 1,240 at 150. A notebook cover printed as one piece is two of those plus the spine.
What dpi do paper products need?
300 dpi is the usual answer for anything held in the hand — stationery, boxes, notebook covers, mugs. 150 dpi is generally accepted for fabric seen at arm's length, but paper close to the eye shows the difference.
Does the repeat have to fit the product exactly?
No. A seamless tile is printed over and over, so the tile's own physical size is what matters, not the product's. What does matter is scale: a 20 cm repeat on a 9 cm mug shows a fragment of the design rather than the design.
How big can the file be?
A browser stops encoding a PNG somewhere around 8,192 pixels on a side, so a surface wider than about 69 cm at 300 dpi, or 138 cm at 150, has to be exported at a lower resolution or in pieces. The calculator above says when you have crossed it.