Surface guide
QR codes on t-shirts and apparel
A QR code on clothing needs 5–10 cm because people scan it from conversational distance, and error correction Q because fabric stretches, wrinkles and distorts the pattern. Print flat-chest or back, never over a seam.
| Typical scan distance | 50 cm–1 m |
|---|---|
| Minimum code width | 5–10 cm |
| Error correction | Q |
Fabric is a hostile substrate
Three things happen that do not happen on paper:
- Stretch. Knit fabric distorts under the wearer, warping the module grid. Alignment patterns correct some of it; a small code with none cannot.
- Weave texture. On coarse fabric the thread pattern adds noise at the module scale.
- Wrinkles. A fold across the code puts halves at different angles and lighting.
Hence Q, and hence a generous size.
Print method
| Method | Suitability |
|---|---|
| Screen print | Best — solid opaque coverage, sharp edges |
| DTG | Good on light fabric, softer edges on dark |
| Vinyl transfer | Sharp, but stiff and cracks with wear |
| Embroidery | Poor — stitch pitch is far too coarse |
| Sublimation | Good on polyester, colours can shift |
Placement
Flat chest, upper back, or a sleeve panel. Never across a seam, a zip, a pocket edge or a shoulder curve. Allow for the code sitting on a curved torso — a slightly larger code tolerates it.
Social reality
People are reluctant to point a phone at a stranger's chest. Codes on merchandise work best on the back, on tote bags, or on staff uniforms where scanning is expected.