NoFussKit field guide
QR code error correction and print checklist
A QR code that looks correct on screen can still fail after printing. Contrast, quiet space, physical size, content length and damage all affect scanning reliability.
What error correction does
QR error correction adds redundant information so a code may remain readable when part is dirty, scratched or covered. Higher levels add more redundancy but also make the pattern denser for the same content.
Level L prioritizes capacity, M is a balanced default, and Q or H can help when a printed code may suffer damage or include a small central logo. Higher is not automatically better when the code must remain physically small.
Protect contrast and quiet space
Use a dark code on a light, plain background. Low contrast, reflective material and busy photographs can make module boundaries difficult for a camera to detect.
Keep an empty margin around all four sides. Do not crop the code tightly or place text and borders against the outer modules. The margin is part of reliable detection, not decorative whitespace.
PNG or SVG
PNG is straightforward for screens and fixed-size documents. Export it at enough pixels for the final placement and avoid enlarging a small raster file after download.
SVG remains vector sharp at different sizes and is often the better master for professional layout or printing. Confirm that the destination software preserves the viewBox and does not alter colors or margins.
Test the real object
Print one sample at final size on the intended material. Scan from different distances, angles and lighting with at least two devices before producing a large batch.
Verify the decoded destination, including protocol and spelling. A visually perfect code can reliably lead to the wrong URL if the encoded text was incorrect.
- Use strong contrast
- Keep clear space around the code
- Prefer SVG as a scalable print master
- Test final size and material
- Scan the decoded destination