QR codes on packaging and labels
On packaging a code has three enemies: a size that is too small, glare from varnish and four-colour printing. Here are the requirements print shops check first.
The file for the print shop
- Send vector — SVG or PDF. A raster file will be resampled to the press screen and the module edges will smear.
- Print a black code with black ink only (100% K), never rich black from four inks: the smallest misregistration adds a colour fringe and the code falls apart.
- A coloured code must be one flat colour without a gradient — gradients on small modules print as patches.
Size and quiet zone
| Surface | Code side | Quiet zone |
|---|---|---|
| Label on a jar or bottle | from 15 mm | 4 modules, at least 2 mm |
| Box, bag | from 20 mm | 4 modules |
| Sachet, stick pack, sample | from 12 mm with a short link | 4 modules |
| Shipping carton | from 30 mm | 4 modules |
The shorter the link, the larger the modules at the same code size. Thirty characters instead of eighty make every square about a third bigger — enough to read a code off a creased label.
Varnish, lamination and material
| Finish | Effect on the code |
|---|---|
| Gloss varnish or gloss lamination | Glares under lamps and cameras often miss the code — ask for matte |
| Spot UV over the code | Better not to apply at all |
| Kraft board | Contrast drops: print the code on a white patch |
| Clear film | A white fill under the code is mandatory |
| Foil stamping | Not suitable — glare and lost edges |
Curves and placement
The code needs a flat area. On a round jar its width should not take more than a third of the circumference, otherwise the camera sees it distorted. Keep the code off box folds, bag seams, flaps and glue lines: it almost always breaks there.
Leave at least 5 mm between the code and the trim line. If the label is trimmed to size, add bleed so the quiet zone does not get cut away.
Before the run, print a proof on the real material and scan it from the distance your customers will use: a metre in a shop window, thirty centimetres on a shelf.
FAQ
What is the minimum code size on packaging?
The practical minimum is 15 mm with a short link and good printing. Anything smaller depends on the press and the material and needs a proof.
Can the code use our brand colour?
Yes, if the code is clearly darker than the background: contrast of 4:1 or better, ideally 7:1. Yellow, light green and light blue do not work for modules.
Can the code be inverted — light on dark?
The standard allows dark modules on a light background only. Some scanners handle inversion, some do not, so avoid it for a print run.
Do we need a separate code per batch?
Not if the link stays the same. If you need batch tracking, put the number in the page address and generate the codes in bulk.