Chapter 55: The Printing Industry's Limitation - Code 39 and the Challenge of Limited Space | 1. A Brief Summary | At its core, Code 39 is a symbology of remarkable utility. Invented in 1974 by David Allais and Raymond Stevens of Intermec, it was the first barcode capable of encoding both numbers and letters, a breakthrough that opened up a world of tracking and identification possibilities across countless industries . Its design---using a series of wide and narrow bars and spaces---is simple, robust, and, perhaps most importantly, it can be read by virtually any barcode scanner in existence. This universal compatibility has made it a mainstay in logistics, industrial automation, medical device tracking, and government applications like the U.S. military's LOGMARS system . | However, this very simplicity is also the source of its most significant technical limitation: a low data density. To encode information, Code 39 uses a 'self-checking' pattern where three out of every nine elements (bars or spaces) are wide . This characteristic, while making it resistant to certain scanning errors, means that the barcode must be physically large to hold even a modest amount of data. This inherent 'long length' is not just an academic drawback; it is a practical bottleneck that severely restricts where and how Code 39 can be used. | The 'real estate' of a product's packaging is a battlefield. For a pallet of goods in a vast warehouse or an industrial shipping container, there is ample space to print a long Code 39 barcode. But the opposite is true for the modern consumer product. A lipstick tube, a medicine vial, an electronic component, or a piece of jewelry has limited surface area. On these small items, every square millimeter is precious for branding, usage instructions, legal information, and visual appeal. When the Chief Marketing Officer demands a bold logo and the legal department insists on an inch of fine print, there is often no room left for a sprawling, information-rich barcode. This is where Code 39's long length becomes an untenable liability, creating a powerful demand for narrower, more data-dense symbologies like Code 128 or Code 93 and, in the modern era, 2D barcodes like QR codes and Data Matrix codes . | This chapter explores this critical limitation. We will delve into the technical roots of Code 39's low density and then, more importantly, journey through a series of real-world industry examples that illustrate how this single constraint has shaped the technology landscape of automatic identification and data capture (AIDC). From the aisles of a grocery store to the sterile rooms of a pharmaceutical lab and the high-speed production lines of the automotive industry, we will see where Code 39 thrives and, crucially, where it has been forced to yield to more space-efficient successors. | 
| 2. The Technical Foundations of 'Long Length' | To understand why Code 39 is unsuited for small packaging, we must first understand the mechanics of its design. The name 'Code 39' is derived from its fundamental encoding pattern. Each character in the standard Code 39 set---be it a number, an uppercase letter, or a symbol---is represented by a pattern of nine elements: five bars and four spaces . Of these nine elements, exactly three are wide and six are narrow. This '3 of 9' rule is the key to its self-checking nature. Because an error in reading a single bar or space is statistically unlikely to produce the correct pattern for another valid character, the code is inherently resistant to misreads . | The characters are also separated by a narrow inter-character gap, which adds to the overall length . The symbology defines a set of only 43 characters (A-Z, 0-9, and seven special characters like '-', '.', '$', '/', '+', '%', and space) . To encode a full range of ASCII characters, an 'Extended Code 39' variant was developed, but it does so by encoding each extended character as a pair of standard Code 39 characters. This clever but cumbersome trick further expands the barcode's length . | This architecture has a direct consequence: data density is low. The barcode itself does not include a check digit, though one can be added for critical applications (using Modulo 43 or 10) . While this keeps the encoding simple and easy to implement---you can literally print a Code 39 barcode using a specialized font---the space required is substantial. | The physical size of a Code 39 symbol is a critical factor. The width of a single narrow element, known as the 'X-dimension,' determines the scale of the entire barcode. The recommended X-dimension for reliable scanning is often around 0.33mm, but a minimum of 0.191mm can be used in high-quality printing environments . The required height of the barcode is also standardized, typically at least 5.0 millimeters or 15% of the symbol's total width, whichever is greater . Furthermore, the barcode must have quiet zones---blank margins on both sides---that are a minimum of 10 times the X-dimension . The formula to estimate the total width of a Code 39 barcode is '(number of characters + 2) * 12 * X' plus the quiet zones. For a barcode of just 10 characters with a 0.33mm X-dimension, this quickly equates to a physical width of over 50mm, not including the mandatory quiet zones . | In the industrial and logistical contexts where Code 39 was first adopted, this length was a non-issue. On a shipping crate, a steel rack, or a file folder, there was plenty of 'real estate.' The problem emerged when the barcode was applied to the product itself. As the miniaturization of consumer goods accelerated and the need for traceability penetrated every corner of commerce, the small product packaging became a challenge that Code 39's architecture simply could not overcome. Its length often forced it to wrap around the edges of a package, making it prone to scanning errors, or it had to be scaled down to the point where the bars were too thin to be reliably read by many scanners, breaking the minimum X-dimension requirements. | 
| 3. Retail and Consumer Goods: Where the Packaging Fights Back | The grocery and consumer goods sector is perhaps the most visible arena where Code 39's size limitation becomes apparent. Walk down the aisles of any supermarket and you will be surrounded by a sea of Universal Product Codes (UPCs), which are a derivative of the Code 39 family of symbologies. While the UPC-A code is the most common, and Code 39 itself is still used in inventory management and retail distribution, the code's length is a major limitation. | 3.1. The Challenge of Small, High-Volume Goods | Imagine the world of small, high-volume consumer goods: a single stick of gum, a tube of lip balm, a keychain, or a packet of seeds. These items are sold in high quantities and require individual identification for inventory management and point-of-sale systems. A Code 39 barcode on a lipstick tube, with its relatively low data density, would need to wrap around the product's circumference or be reduced to an unreadably small size. The X-dimension would become too small for standard retail scanners, and the length of the symbol would likely extend beyond the available space on the label. This forced a move to more compact symbologies. | The search for a narrower symbology was a direct response to this retail floor pressure. Code 128, developed in 1981, became the de facto standard for logistics and retail shelf labeling because it offered more than double the data density of Code 39. It could encode the same information in a much smaller footprint. Furthermore, the emergence of the UPC and EAN codes, which were standardized and optimized for retail point-of-sale scanning, further cemented the shift away from Code 39 for consumer-facing product identification. These barcodes were short, numeric-only, and designed for high-speed scanning, making them the antithesis of the long and alphanumeric Code 39 . | 
| 3.2. The Modern Shift to 2D Barcodes | The pressure on small packaging has only intensified in the modern era. While Code 39 was too long, and later linear codes like Code 128 were an improvement, the consumer goods industry is now actively moving beyond linear barcodes altogether. A recent pilot project by Fazer, S Group, and GS1 Finland exemplifies this trend. They tested the use of a dynamic 2D code on consumer packaging---in this case, a candy bag. This new code, which looks like a QR code, contains a unique product number (GTIN) but also includes a link to consumer-facing content and variable batch-specific information like best-before dates and production lot numbers . | This innovation is a direct response to the limitations of all linear barcodes, including Code 39 and its successors. As regulations around product traceability increase, there is a growing need to pack more information onto the packaging. The 2D code can hold a wealth of information and be dynamically updated, while also being scannable with a smartphone camera. The pilot's aim is to assess the concrete benefits of 2D codes in the value chain, highlighting that while linear barcodes served a purpose, the future of product identification lies in high-density, data-rich 2D symbologies that can meet the needs of both retailers and consumers. | 
| 4. The Medical and Pharmaceutical Sector: A Tight Squeeze in a High-Stakes Environment | The medical device and pharmaceutical industries are governed by a rigorous framework of regulation and traceability. Products must be uniquely identified to track them through the supply chain, ensure authenticity, and manage recalls. Code 39 has a long history here, largely due to its simplicity, widespread scanner support, and the presence of human-readable text, which is beneficial for manual visual inspections . However, the physical constraints of medical packaging and the critical need for data integrity have also pushed the industry to find more compact solutions. | 4.1. The Challenge of Vials, Syringes, and Ampules | Consider the packaging of a pharmaceutical product: a small glass vial, a plastic syringe, or a delicate ampule. These are the ultimate 'small real estate' scenarios. The area available for labeling is often a small, curved surface on a tiny bottle, a few square centimeters on a syringe barrel, or a flat panel on a blister pack. These packages must carry a wealth of information, including the drug name, dosage, lot number, and expiration date---precisely the kind of data that a Code 39 barcode could encode. But the barcode itself would need to be long, making it difficult to fit in the allotted space. | The solution for many medical applications has been to use Code 128 or, increasingly, a high-density 2D data matrix code. The Data Matrix code, in particular, has become a cornerstone of medical device and pharmaceutical identification. It can encode up to 2,335 alphanumeric characters in a very small space and includes error correction, making it more robust against physical damage and printing imperfections. With regulations requiring clear and easily visible unique identifiers on each unit, the Data Matrix code's ability to fit a large amount of data into a tiny square has made it an indispensable tool. | The push for traceability in the pharmaceutical sector is so strong that laser marking technologies have been developed to directly etch codes onto products, such as medical devices and pharmaceutical packaging . Laser systems can mark high-quality Data Matrix codes and other symbologies directly onto the material, offering a permanent and tamper-evident solution that is immune to smudging, peeling, or wear---a crucial requirement for medical products that may be exposed to sterilization processes or solvents. | 
| 4.2. A Direct Comparison | To illustrate the point, imagine encoding a simple identification string 'ABC1234' on a vial. A Code 39 barcode would be long and would need to be scaled down to fit the narrow label of a syringe. The narrow bars might become thinner than the minimum recommended size, increasing the chance of a scanning error. A Code 128 code, using the same narrow bar width, would be significantly shorter, allowing it to fit comfortably on the label without sacrificing readability. A Data Matrix code, being a 2D symbol, would be a fraction of the size, a small square that could be laser-etched onto the cap of the vial. | This scenario is a classic illustration of 'The Printing Industry's Limitation.' The barcode's print quality and physical size are constrained by the scanner's ability to read it and the printer's ability to produce it. The Code 39's length makes it a poor choice when the label is small, forcing the printer to compress the barcode to the point where the quiet zones and X-dimension are violated. This can lead to unreadable or misread barcodes, which is not just an inconvenience but a serious safety hazard in a medical context. | 
| 5. Industrial Applications: The Battle for Space on the Production Line | The industrial sector, from automotive manufacturing to electronics assembly, relies heavily on barcodes for tracking work-in-progress, managing inventory, and ensuring quality control. Code 39 was an early pioneer in this domain due to its simplicity and ruggedness, but even here, the pressure to minimize size is palpable. | 5.1. Electronic Components: The Micro-Scale Challenge | Electronic components like tiny resistors, capacitors, microchips, and circuit boards are the ultimate 'small product' for industrial barcoding. These are the items that Code 39 was never designed to handle. The surface area on a microchip is often just a few square millimeters, and the traceability required extends to lot codes and date codes, which can be multiple characters long. Code 39's long length makes it virtually unusable for such applications. Instead, the industry has embraced high-density 2D codes, especially Data Matrix, which can be printed or laser-marked directly onto the component with a fraction of the required footprint. This allows for the tracking of a single component throughout its lifecycle, even when it is mounted onto a circuit board, using specialized 'microlens' scanners. | 5.2. Tracking Within a Factory | In other areas of the factory, the availability of space is more variable. When tracking large assemblies, such as a car chassis moving along an assembly line or a large storage container, a Code 39 barcode is perfectly adequate. There is ample space for the long symbol on the chassis or the side of the container. However, smaller components, tools, or fixtures also need to be tracked. A socket wrench in a maintenance bay, a specialized fixture, or a jig used in a manufacturing process often has limited surface area for a label. The label must be small enough to be attached to the tool without interfering with its function, yet robust enough to survive the harsh environment of a factory floor. In such cases, a short Code 128 or a small Data Matrix symbol is often the pragmatic choice. | 5.3. Logistics and Warehouse Management | In the broader world of logistics and warehouse management, the story is one of coexistence. Code 39 continues to be widely used on shipping labels and for pallet tracking due to its universal scanner compatibility and the fact that there is abundant space on the packaging materials . However, the trend is also toward using more efficient codes for internal applications. For instance, many warehouse management systems (WMS) use Code 128 to encode more data---such as order numbers, pick lists, and location codes---onto a single label without consuming too much space. | 
| 6. Government, Military, and Library Use | 6.1. The LOGMARS Standard | The U.S. military's LOGMARS (Logistics Applications of Automated Marking and Reading Symbols) standard was one of the first major adopters of Code 39, and it is a testament to the symbology's durability and robustness . The military needed a barcode that could be printed on a wide range of materials, survive harsh conditions, and be read by a variety of equipment. Code 39, with its simplicity and self-checking nature, fit the bill. In the military supply chain, the barcode is used on everything from shipping containers to ammunition crates and large equipment. In these applications, space is not a primary concern. The barcode can be large, and its low density is not a disadvantage. The consistent presence of the * start and stop characters in the human-readable text also helped in visual identification, a key consideration for military personnel who might be dealing with unfamiliar or damaged labels . | 6.2. Libraries and Archival Systems | Libraries have been another major adopter of Code 39, often using it for patron IDs and for identifying books, journals, and other media. The barcode is typically placed on a blank area on the back cover or inside the front cover of a book. Libraries have ample space for this, as books provide a relatively large, flat surface. The barcode's length is not an issue, and the ability to use a simple font to generate it has made it easy for libraries to implement their own systems. However, even libraries are starting to feel the pressure. As they digitize their collections and adopt sophisticated inventory management systems, there is a growing need to encode more information, such as a book's location, status, and borrowing history, directly into the barcode. This has led some to consider using Code 128 or other more compact symbologies, but Code 39 remains the most common standard for library barcode labels today due to its legacy and widespread scanner support . | 
| 7. The Technical Workarounds and Their Limits | Faced with the space constraint, the industry did not simply abandon Code 39. Several workarounds were attempted and, in some cases, adopted. | 7.1. Scaling Down the X-Dimension | The simplest approach to making a Code 39 barcode fit in a small space is to reduce the X-dimension. Printing the barcode with narrower bars makes the entire symbol smaller. However, this approach hits a limit quickly. The scanning hardware must be able to resolve the narrow bars. Many older or lower-quality scanners might struggle to read a barcode with an X-dimension below 0.191mm. This workaround is also constrained by the printing technology. A typical inkjet or laser printer may not be able to produce consistently sharp edges at such small sizes, leading to 'substitution' errors where a wide bar is misread as a narrow one, or vice versa, disrupting the self-checking nature of the code. High-resolution printers, often with 300 DPI or more, are required, adding cost and complexity to the printing process . | 7.2. Truncating the Barcode Height | Another common workaround is to reduce the height of the barcode. Code 39's height, or 'bar height,' is a measure of its vertical extent. While a taller barcode is easier to scan (it allows for a wider sweep area), a shorter barcode is sometimes used to save space. However, this is a dangerous practice. If the barcode is too short, the scanner might misread it as two separate symbols or fail to read it at all. The standard recommends a minimum height of 5mm or 15% of the length, which is a guideline that many applications simply cannot meet . | 7.3. The Extended Code 39 | The 'Extended Code 39' variant was an attempt to increase the character set, allowing for lowercase letters and additional symbols. It achieved this by encoding each extended character as a pair of standard Code 39 characters. This doubled (or more) the length of the barcode for those characters, making the space problem even worse. It also introduced compatibility issues, as most standard barcode scanners must be specially configured to read Extended Code 39 . This feature meant that a simple barcode font would not work, and the need for specialized hardware made it an impractical solution for many use cases. | 
| 8. Case Study: The Tobacco Industry's Traceability Imperative | The tobacco industry provides a powerful, real-world illustration of how traceability requirements have forced a move away from Code 39's long length. Due to high taxation and stringent anti-counterfeiting measures, tobacco products are subject to robust track-and-trace regulations. Each individual packet of cigarettes or a pack of cigars is required to carry a unique identifier that can be tracked from the factory to the point of sale . | This presents a monumental challenge. Each packet is tiny, and the packaging is already dense with legal warnings and branding. A Code 39 barcode on an individual pack is simply too long. In response, the industry has adopted high-speed, high-precision laser marking to print 2D QR-like codes directly onto the packaging material. Companies like Hans Laser have developed specialized systems that can rapidly apply these 2D codes during the manufacturing process . These systems are integrated with database management software to link the unique code on each pack to a master carton and, ultimately, to a pallet, enabling end-to-end traceability. | This case study is a perfect encapsulation of the 'Printing Industry's Limitation.' The physical limitations of Code 39's length and the limited space on the product's packaging created a technological bottleneck. The regulatory requirement for traceability could not be met by using Code 39. This demand---what we might call 'the demand for narrower symbologies'---drove the adoption of a completely different paradigm: the 2D code and the sophisticated laser marking and data management systems required to support it. Code 39's reign in this sector is effectively over, superseded by technologies that can pack more information into less space, while also providing greater security and robustness. | 
| 9. Conclusion: A Detailed Summary | The story of Code 39's limitation in the printing industry is a classic tale of a technology's success becoming a constraint on its further application. Code 39's power lies in its simplicity and compatibility. It was the first alphanumeric barcode, and its self-checking nature, combined with its easy integration into existing printing systems, made it the backbone of a generation of tracking and identification systems. It became the preferred symbology for logistics, industrial automation, library systems, and government applications, reaching its pinnacle with the LOGMARS standard of the U.S. military. | However, this very success created a problem. The code's low data density, a direct consequence of its '3 of 9' encoding rule, meant that it was physically long. This was not an issue for large items like shipping crates or machinery, but it was a significant and often insurmountable problem for the growing world of smaller, high-value consumer goods and industrial components. As the retail, medical, and manufacturing sectors demanded more traceability at the individual product level, the space on product packaging---the 'real estate'---became a critical, scarce resource. | 
| This limitation is not an abstract technical detail. It manifests in the real world in a multitude of ways: | - In retail, Code 39's length made it impractical for small items like lipstick or gum, paving the way for UPCs and Code 128, and now for dynamic 2D barcodes that can link to a wealth of information. | - In the medical and pharmaceutical field, the small surface area of vials and syringes made Code 39 a risk, as a shortened or compressed barcode might be unreadable or lead to a medical error. This drove the adoption of tiny Data Matrix codes and laser marking for permanent, tamper-evident identification. | - In industry, while Code 39 still thrives on large equipment, it is wholly inadequate for tracking microchips and other tiny components. The electronics sector, in particular, has long abandoned it in favor of 2D codes that can be placed even on a single transistor. | - In the tobacco industry, the stringent regulatory need for item-level traceability simply could not be met by Code 39. This forced the adoption of high-speed laser marking systems that print 2D QR-like codes directly onto the tiny packets, linking them to a comprehensive database. | The search for narrower symbologies was not merely a preference but a necessity. Code 128 offered a significant improvement in data density while remaining linear and compatible with most scanners. More recently, 2D codes like Data Matrix and QR codes have become the ultimate solution for small-space applications, packing a wealth of data and error correction into a minuscule footprint. | 
| Ultimately, Code 39's long length was a crucial factor in its own evolution and in the diversification of the barcode world. It was the success and ubiquity of Code 39 that created a demand for higher-density and more flexible solutions. While Code 39 remains a vital and active standard in many large-scale and logistical applications where space is not a constraint, its direct application to small product packaging is a dying art, a poignant reminder of the fundamental 'limitation' that drove the barcode industry to innovate and find the next generation of traceability technology. The legacy of Code 39 is not just its own history, but the innovation it spurred, demonstrating that sometimes, the most profound impact a technology can have is to reveal its own boundaries. |
|
cs@easiersoft.com