A 2D code can look clear to the human eye and still fail to scan reliably in production, logistics or at the point of sale.
That is why 2D code verification matters. It goes beyond confirming that a scanner can read a QR code or Data Matrix once. It measures whether the symbol has the quality required to be read consistently by the systems, customers and partners that need to use it.
For manufacturers adopting 2D codes for traceability, serialisation, product information or GS1 Digital Link, verification should be part of the production process—not a final check after a problem appears.
What is 2D code verification?
2D code verification is the process of measuring the quality of a printed or marked code against defined technical criteria.
A verifier assesses the symbol and generates a quality grade. Depending on the application, it can evaluate characteristics such as contrast, symbol dimensions, damage to fixed patterns, modulation, grid uniformity and error correction.
This is different from simply scanning a code.
A scanner or camera confirms whether it can decode a symbol under specific conditions. A verifier assesses whether that symbol is likely to be read reliably by other compatible systems throughout the supply chain.
Why reading a code is not enough
A code may scan successfully on the production line but fail later because it was read using a high-performance camera, ideal lighting or a fixed position that does not reflect real-life conditions.
The same code may become difficult to read when it is:
- Scanned at high speed.
- Printed on curved or reflective packaging.
- Damaged during sealing, handling or transport.
- Covered by condensation, frost or abrasion.
- Read by a different scanner in a warehouse or retail environment.
- Positioned too close to pack edges, seams or graphics.
Verification helps identify these risks before a poor-quality code reaches a customer, distributor, pharmacy, warehouse or retail store.
2D code verification and GS1 requirements
For GS1 DataMatrix and QR codes, code quality is not only about appearance. It also depends on whether the symbol is correctly constructed, carries the right data and meets the requirements of the intended application.
GS1 guidance highlights that barcode quality combines ISO/IEC technical specifications with GS1 General Specifications. The required grade can vary according to the code type, its application and where it will be scanned. GS1
This is particularly relevant as manufacturers prepare for wider use of GS1 2D barcodes in retail, healthcare, logistics and industrial traceability.
What does a 2D code verifier check?
The exact criteria depend on the symbology and application, but a verification process may assess the following elements.
Symbol contrast
The contrast between the dark and light areas of the symbol has a direct impact on readability. Low contrast can be caused by unsuitable packaging colours, inconsistent marking, glossy surfaces or poor interaction between the code and the substrate.
Code size and X-dimension
A code that is too small for the printing or marking process may lose definition. The X-dimension, or module size, needs to be suitable for the data content, available space, print technology and scanning environment.
Quiet zone
A 2D code needs sufficient clear space around it. If graphics, text, seals, pack edges or other printed information interfere with this area, scanners may struggle to identify the symbol correctly.
Print or mark quality
Missing modules, blurred edges, ink spread, low definition, wrinkles or damage to the symbol can reduce code quality. On flexible packaging, these issues can be influenced by film movement, tension, sealing and substrate variation.
Data accuracy
A code may be readable but still contain the wrong information. Verification of the symbol should be combined with data validation to ensure that the encoded data matches the active product, batch, date, serial number or production job.
Verification versus validation: what is the difference?
These two terms are often used interchangeably, but they solve different problems.
| Process | What it checks |
|---|---|
| Code reading | Whether a scanner can decode the symbol at that moment |
| Verification | Whether the symbol meets defined quality requirements |
| Validation | Whether the encoded data is correct for the product and production job |
A complete quality-control process should consider all three.
For example, a vision system may read a Data Matrix code and confirm that it contains the expected batch number. A verifier can then assess whether the physical symbol meets the required print-quality criteria.
Printed codes and direct part marking require different approaches
Not all 2D codes are applied to labels or packaging.
In automotive, electronics, medical devices and industrial manufacturing, codes are often marked directly onto metal, plastic or coated components. This is known as direct part marking, or DPM.
Direct part marking presents additional challenges because the code may be engraved, annealed, ablated or created through a change in surface finish. Reflective metals, curved parts, textured plastics and low-contrast marks can all affect how the code is evaluated.
For printed 2D symbols, ISO/IEC 15415 is commonly used to assess print quality. Direct part marks may require a different verification method and suitable lighting conditions. The relevant requirement will depend on the application, customer specification and industry standard.
Common causes of poor 2D code quality
Many 2D code failures can be prevented by reviewing the application before production starts.
Common causes include:
- Insufficient contrast between the code and the substrate.
- An unsuitable code size for the available print area.
- Excessive data encoded into a small symbol.
- Film wrinkles or substrate movement.
- Inconsistent print position.
- Curved, glossy or reflective surfaces.
- Poor code placement near a seal, edge or fold.
- Incorrect laser parameters or ink settings.
- Inadequate quiet zone.
- Damaged or worn packaging after production.
A code should always be assessed on the final product, not only on a test sample.
How to build 2D code verification into production
Effective verification begins before the line is running.
First, define the code’s purpose. Is it for retail scanning, internal traceability, serialisation, warehouse automation, regulatory compliance or consumer engagement? The intended use will influence the data structure, symbology, size and quality target.
Next, test the code on the actual packaging or component. Production conditions matter: line speed, material variation, temperature, moisture, marking position and downstream handling can all affect the final result.
Finally, create a clear process for ongoing control. This may include:
- Approving a reference sample at line start-up.
- Validating variable data at product changeovers.
- Carrying out periodic verification checks.
- Defining actions for failed or borderline codes.
- Recording results for quality and traceability purposes.
- Reviewing code quality when packaging materials or artwork change.
Verification should be treated as a preventive quality-control step, not only as a response to a rejected product or customer complaint.
Choosing the right marking solution for 2D codes
The best marking technology depends on the application.
Flexible films may require a solution that delivers consistent contrast at speed without affecting the packaging. Bottles, cartons and labels may present different challenges in terms of material, curvature and available coding area. Industrial components may need permanent direct marking that remains readable after assembly, use and exposure to demanding environments.
At Macsa id, we assess the code, material, production conditions and traceability objective together. This helps manufacturers apply 2D codes that are not only visible, but dependable throughout the product lifecycle.