The key parameters that affect QR code scan success: quiet zone, size, and color contrast.
Quiet zone directly affects recognition
The blank area around a QR code is how scanners locate it. Too little padding makes the code impossible to scan.
Ensure enough padding first, then set the size. Avoid trimming the blank area after export.
Avoid low-contrast color combinations
Dark foreground on a light background is the safest. Bright foreground colors reduce recognition rates noticeably.
If you must use color, scan the code with a real phone before shipping it to materials.
Content determines error tolerance
Longer content makes the code denser and harder to scan. Prefer short URLs and plain text over long strings.
Export the PNG at its original size. Do not recompress it for layout, which can lose detail.