Guide to Barcode Symbologies

PDF417 Barcode

 

Example of PDF417

PDF417

 

PDF417 is a two-dimensional (2D), high-density, stacked barcode symbology designed for storing large amounts of data in a compact and highly reliable format. The name PDF417 stands for “Portable Data File”, reflecting its original purpose of encoding complex datasets rather than simple identifiers.

The term stacked refers to the way multiple small linear barcodes are layered on top of each other to form a single 2D symbol. A PDF417 barcode can contain between 3 and 90 rows, allowing it to scale flexibly depending on the amount of information that needs to be encoded.

Data Capacity and Encoding

One of PDF417’s greatest strengths is its large data capacity. It can encode the full 255-character ASCII character set, as well as binary data (8-bit byte data), making it suitable for mixed data formats such as text, numbers, and machine-readable data stored together in a single symbol.

This capability allows PDF417 barcodes to store significantly more information than traditional 1D barcodes, often replacing databases or manual data entry entirely in certain applications.

Error Correction and Reliability

PDF417 includes built-in error correction, allowing damaged or partially obscured barcodes to remain readable. This makes it highly reliable in environments where barcodes may suffer wear, handling damage, or less-than-perfect print conditions.

Because PDF417 is a bi-directional symbology, it can be scanned from multiple orientations, further improving read success rates in real-world use.

Scanner and Printing Considerations

Due to the density and two-dimensional structure of PDF417 barcodes, scanner quality is critical. For consistent and reliable reading, the use of a high-quality CCD scanner or camera-based barcode reader is strongly recommended.

Low-resolution laser scanners may struggle with PDF417 symbols, particularly when barcodes are printed at smaller sizes or contain large volumes of data. Proper print quality and contrast are also essential to ensure accurate scanning.

Common Uses of PDF417 Barcodes

PDF417 is widely used in applications where large amounts of structured data must be stored securely and read reliably. Common use cases include:

  • Identity documents (driving licences, ID cards, visas)

  • Transport and logistics documentation

  • Boarding passes and travel documents

  • Inventory and asset tracking systems

  • Government and secure identification systems

Its ability to encode detailed datasets makes PDF417 especially valuable in regulated or data-heavy environments.

Limitations and Considerations

While PDF417 offers exceptional capacity and reliability, its size and scanning requirements mean it may not be suitable for very small labels or low-cost scanning environments. In such cases, other 2D symbologies may be considered depending on the data requirements and scanning infrastructure.

Summary

PDF417 is a powerful, high-capacity 2D stacked barcode symbology capable of encoding large amounts of text and binary data with excellent reliability. With built-in error correction and broad industry adoption, it is ideal for identity documents, transport systems, and applications where complex data must be stored directly within the barcode.