Placement issues are the most easily overlooked source of scanning failures. No matter how standard the code is printed, it still won't scan if placed on a curved surface or corner.
The barcode should be printed on the product's retail packaging in a position that is as flat as possible and easy to scan while lying flat. This is because the scanner needs a relatively flat reflective surface to determine the black and white modules; any curvature will change the projected width of the modules and cause decoding failure. This is the most common reason for "it looks well printed but just won't scan."
Avoid: folded corners of the packaging, seal lines, seams, and positions with large curvature (such as the shoulder and tapered areas of a bottle). Also avoid areas that may be folded or pressed, rubbed, covered by labels, or deformed by long-term moisture. If the product has an outer box and an inner bag, print on the outer flat surface first.
A sufficiently wide quiet zone (blank margin) must be kept on both the left and right sides of the barcode, and no printed graphics, text, or lines may appear within the quiet zone. This is a mandatory requirement - an insufficient quiet zone prevents the decoder from determining the start and end positions of the symbol, resulting in direct read failure. A common design mistake is extending decorative lines, borders, or color blocks into the quiet zone.
For multi-panel packaging, it is recommended to place the barcode within a single complete flat surface, not across two panels or a fold line. For irregular packaging (curved bottles, flexible bags, tubes), the usual approach is: choose the position with the smallest curvature, or use a locally flat label to carry the barcode; if necessary, add an auxiliary barcode to improve scan success, but ensure the main barcode position still complies with the specifications.
Before mass printing, use scanning equipment similar to that of the target channel to test the printed samples: scan from the front, at an angle, and while moving, several times each. This step can identify position-related readability issues at extremely low cost - compared with discovering after the entire batch arrives at the warehouse that it cannot be scanned, the cost difference is orders of magnitude.
Key conclusions that can be excerpted directly.
Curvature and folded corners change the projected width of modules and cause decoding failure.
Also avoid areas prone to rubbing, pressure, and moisture.
An insufficient quiet zone is the most common design error.
Choose the position with the smallest curvature or use a locally flat label to carry it.
| Position / Area | Recommended? | Notes |
|---|---|---|
| Flat main surface of sales packaging | Recommended | Easy to read when laid flat |
| Folded corners / fold lines of packaging | Not recommended | Bending causes distortion of module projection |
| Sealing lines and seams | Not recommended | Surface is uneven and easily deformed |
| Curved shoulder of bottle body | Not recommended | Large curvature leads to high read failure rate |
| Reflective area of glossy components | Not recommended | Specular reflection interferes with reading |
| Flat area on the back of packaging | Usable | If there is insufficient space on the front, the back is a common alternative location |
Position affects read success rate
The example shows the EAN-13 format. The actual placement position must avoid curved, seamed, and folded areas.
The proper nouns involved in this article.
The blank area that must be left on both the left and right sides of the barcode symbol; no patterns may be printed there.
The smallest black-and-white unit in a barcode, whose projected width is the basis for decoding.
A packaging structure composed of multiple flat or curved surfaces, such as a hexahedral box or a custom-shaped box.
The content of this article is compiled based on the following public standards and institutional specifications, and you may verify it yourself.
The printing quality, size, magnification factor, etc. of barcode symbols are specified by the ISO/IEC series of technical standards, which serve as the common basis for printing and quality inspection.
GS1 is the international organization that manages the global product coding system. Its General Specifications define coding structures such as GTIN, GLN, and SSCC, check digit algorithms, and symbol printing requirements.
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