Barcode and QR Code: Invention, Adoption, and Encoding

A barcode is a printed series of parallel bars or lines of varying width that is used for entering data into a computer system.¹ In its original form, this pattern constituted a linear, one-dimensional (1D) code, a format that remains the basis for the most familiar symbols.² Such codes are read by optical scanners called barcode readers, devices that translate the alternating bars and spaces into machine-readable information.¹ Because the code is a printed marking rather than an electronic component, it can be printed on various materials, including paper and plastic.¹ This combination of a simple printed symbol and an optical reading device makes the barcode a practical interface between physical objects and computer systems, a role it has sustained across many sectors of commerce and industry.¹

Within the category of 1D barcodes, several symbologies have become established, among them UPC, EAN, Code 39, and Code 128.³ These linear symbols are limited in data capacity compared to 2D barcodes, a constraint inherent in a format that encodes information along a single dimension.² The code itself carries no meaning until a reader captures it; the scanner converts the printed pattern into data that a computer system can process, which is the defining function of the technology.¹ Although the barcode is most often associated with retail packaging, its use extends to the identification of products, locations, and assets.⁴ The physical simplicity of the printed symbol, paired with the speed of optical reading, explains why the barcode has become a standard means of automatic identification across diverse applications.²

The barcode is not a single standardized design but a family of formats united by a common principle: encoded variation in printed bars or lines, captured optically and entered into a computer system.¹ Common 1D symbologies, including UPC, EAN, Code 39, and Code 128, share the linear structure, while serving different identification needs.³ The earliest barcode designs were themselves linear, one-dimensional codes, establishing the template that later symbologies refined.² The technology has since spread into healthcare, transportation, and manufacturing, among other sectors.¹ Because barcodes can be printed on materials such as paper and plastic, they can be affixed directly to goods, packaging, and documents, allowing a printed mark to function as a durable and inexpensive data entry interface.¹

The first barcode was invented by Norman Joseph Woodland and Bernard Silver, who patented it in 1952⁵. The idea of a barcode was inspired by Morse code². The original barcode patent described classifying articles using identifying marks⁶. Woodland and Silver's initial barcode design was a bull's-eye pattern, not the linear bars we see today⁵. The first barcode was a linear, one-dimensional (1D) code..²

The 1952 patent outlined a method and apparatus for classifying articles by means of identifying marks, establishing the conceptual foundation for automated identification⁶. Woodland and Silver’s original design used a bull's-eye pattern of concentric circles, which differed from the linear bars that later became standard⁵. Despite this initial circular form, the first barcode is characterized as a linear, one-dimensional code, reflecting its encoding along a single axis². The inspiration from Morse code informed the representation of data through varying widths and spacings, a principle that persisted in subsequent barcode symbologies..²

The pioneering work of Woodland and Silver, patented in 1952, described a method for classifying articles using identifying marks, which set the stage for later developments in barcode technology⁶. Their initial bull's-eye design, though not the linear bars seen today, was a crucial step in the evolution of machine-readable codes⁵. The first barcode is recognized as a linear, one-dimensional code, a format that would dominate early applications². The inspiration from Morse code provided the foundational idea of encoding information in a pattern of marks, which was adapted into the barcode concept..²

The barcode began its practical life far from the retail aisle. The barcode was initially used in railcars to track wagons, an application that suited the technology's capacity to identify moving objects with a printed mark. The original barcode patent described classifying articles using identifying marks, an early statement of the principle that would guide later deployments. The first barcode was a linear, one-dimensional (1D) code, and it was read by optical scanners called barcode readers. These early industrial uses demonstrated that a printed symbol could serve as a reliable bridge between a physical object and a computer system.²

Widespread adoption depended on hardware as much as on the symbols themselves. The development of the laser scanner was crucial for the widespread adoption of barcodes, because rapid, reliable reading at the point of sale transformed the barcode from a niche tracking tool into a general retail mechanism. IBM played a key role in developing the technology for barcode scanning in retail, contributing the engineering that made scanning practical for merchants. Retail adoption brought measurable operational gains: the adoption of barcodes in retail reduced labor costs and improved inventory accuracy. The UPC was adopted as the standard for retail packaging in the United States in 1973, giving the industry a common language.⁵

The same reading technologies soon reached beyond the store. The IBM 3600 Finance Communication System was the first to use magnetic stripe and barcode readers for banking, extending automatic identification into financial services. This migration showed that barcode and magnetic stripe readers could support not only product identification but also account and transaction handling. The first UPC barcode was scanned at a supermarket in 1974, and the UPC barcode is now used on millions of products worldwide. Taken together, these developments trace a path from railcar tracking to retail checkout and then into banking, each step resting on scanners capable of reading printed marks accurately and quickly.⁷

In 1973 the Universal Product Code was adopted as the standard for retail packaging in the United States, establishing a common machine-readable identifier for goods sold at retail. The code belongs to the family of one-dimensional symbologies—alongside EAN, Code 39, and Code 128—that dominate automatic identification. Its rise depended on parallel advances in reading equipment, since the laser scanner was pivotal to the widespread adoption of barcodes and IBM played a key role in developing the technology for barcode scanning in retail. Together, the standard and the scanner turned a printed pattern of parallel bars into a practical interface between packaged goods and computer systems.⁴

The first UPC barcode was scanned at a supermarket in 1974, an event that marked the transition of the code from specification to daily use. The first barcode scanner was installed in a supermarket in that same year. The first product read was a 10-pack of Wrigley's Juicy Fruit gum, scanned on June 26, 1974, at a Marsh supermarket in Troy, Ohio. That single transaction, repeated across checkout lanes, demonstrated that standardized marking and optical scanning could operate reliably at the point of sale, where speed and accuracy are essential.⁵

The consequences for retail operations were substantial: the adoption of barcodes in retail reduced labor costs and improved inventory accuracy. What began as a single scanned pack of gum became a universal practice, and the UPC barcode is now used on millions of products worldwide. The code thereby became part of the basic infrastructure of commerce, linking each item to a unique number and enabling stores to record sales and stock movements as routine data rather than manual estimates.⁴

The earliest barcode was a linear, one-dimensional (1D) code². A barcode is a printed series of parallel bars or lines of varying width used for entering data into a computer system¹, and among linear symbologies the most common are UPC, EAN, Code 39, and Code 128³. In the United States, the Universal Product Code was adopted as the standard for retail packaging in 1973⁴, a decision that placed machine-readable identification on consumer goods at national scale⁴. These linear formats read by optical scanners, called barcode readers, became the technical basis for automated data capture in commerce..¹

International retail relies substantially on EAN-13, a 13-digit barcode used globally for retail products⁴. Such barcodes are used to identify products, locations, and assets⁴, and to keep those identifications unique across manufacturers, GS1 assigns company prefixes for barcodes⁴. GS1 standards include barcodes for retail, healthcare, and logistics⁴, reflecting the breadth of applications that depend on the same numbering discipline, spanning retail, logistics, and healthcare². The prefix system therefore underwrites the reliability of 1D symbols wherever a product must be distinguished from every other item in a database..⁴

The principal constraint of these formats is capacity: linear barcodes are limited in data capacity compared to 2D barcodes². This limitation reflects their physical design, in which data is encoded along a single axis of parallel bars rather than across a grid¹. Verification practice measures the quality of a barcode symbol according to ISO/IEC 15416³, and such measures ensure that barcodes meet quality standards for accurate scanning³. Where larger payloads or reading from any direction are required, those requirements exceed what 1D symbologies are engineered to provide, and other code types are adopted instead..²

The QR Code was invented in 1994 by Masahiro Hara of DENSO WAVE, marking a distinct departure from the linear barcode formats that had dominated automatic identification since the mid-twentieth century. The name itself is an abbreviation: QR Code stands for 'Quick Response'. This designation reflects the design priorities of its creators, who sought a symbology capable of being decoded rapidly rather than merely storing a short string of characters. The QR Code is a two-dimensional code that can be read at high speed, a property that distinguished it from the one-dimensional barcodes then in common use.⁸

The impetus for theQR Code's development was industrial rather than retail. The QR Code was developed to track automotive parts, a setting in which conventional linear barcodes posed practical limitations for manufacturers seeking finer-grained tracking of components through production and logistics. The resulting two-dimensional format was engineered to meet the demands of that environment, where speed and reliability of reading mattered greatly. Its emergence thus answered a specific need within automotive manufacturing before it spread to the broader applications for which two-dimensional codes later became known.⁸

A pivotal decision shaped the QR Code's subsequent trajectory: DENSO WAVE made the QR Code specification publicly available and royalty-free. By releasing the specification without licensing restrictions, DENSO WAVE allowed other manufacturers, developers, and standards bodies to implement the symbology without seeking permission or paying fees. This openness enabled the QR Code to circulate far beyond its original automotive context and to be adopted across industries and, eventually, by the general public. The royalty-free release stands as a deliberate choice that contrasted with a purely proprietary approach to the technology.⁸

A QR code consists of black squares arranged in a square grid on a white background, a construction that distinguishes it from the linear symbols of conventional barcodes ⁹. The code incorporates finder patterns that help scanners locate and orient the symbol, so that a reader can establish its position and rotation before decoding begins ⁹. This design allows QR codes to be read from any direction, unlike traditional barcodes that require alignment ⁹. The result is a symbology that is a two-dimensional code, and one that can be read at high speed ..⁸

Symbol sizes are organized into QR Code versions that range from 1 to 40, with increasing module counts as the version number rises ¹⁰. This progression of versions supports capacities of up to 7,089 numeric characters, 4,296 alphanumeric characters, or 2,953 bytes ⁹. The symbology can encode Kanji characters efficiently, extending its practical use in Japanese-language applications ⁸. These encoding options are governed by the QR Code specification, ISO/IEC 18004:2015, which defines the characteristics, data character encoding methods, symbol formats, dimensional characteristics, error correction rules, reference decoding algorithm, production quality requirements, and user-selectable application parameters ..¹⁰

QR codes can be read by smartphones and dedicated scanners, a factor that has helped them move beyond industrial settings into everyday use ⁹. Typical encoded content includes URLs, contact information, and text ⁹. The same symbols are used for mobile payment, product tracking, and digital ticketing ⁹. The specification underlying these capabilities originates from the QR Code development work carried out at DENSO WAVE ..⁸

The QR Code incorporates error correction capabilities that allow it to be read even if part of the code is damaged.⁸ This feature distinguishes the symbology from conventional linear designs, whose fixed bar patterns offer no comparable resilience when the printed symbol is partially obscured or degraded. The correction mechanism operates through defined levels, designated L (7%), M (15%), Q (25%), and H (30%), each representing a distinct proportion of recoverable data.¹⁰ Selecting among these levels lets an implementer trade data capacity against robustness, so that symbols deployed in demanding environments can tolerate greater physical loss while still returning the encoded information to the scanning device.¹⁰

Formal standardization arrived when the QR code was published as ISO/IEC 18004 in 2000.⁹ The standard specifies the QR Code symbology characteristics together with its data character encoding methods, symbol formats, dimensional characteristics, error correction rules, reference decoding algorithm, production quality requirements, and user-selectable application parameters.¹⁰ By fixing these elements in a single document, the specification provides a common technical basis for symbol generation, printing, and interpretation across independent manufacturers and reading equipment.¹⁰

Responsibility for the standard rests with ISO/IEC JTC 1/SC 31, the committee that maintains ISO/IEC 18004.¹⁰ Ongoing maintenance keeps the symbology definition aligned with the encoding and decoding requirements set out in the specification.¹⁰ Because the standard addresses error correction rules alongside encoding methods and symbol formats, the levels L, M, Q, and H are governed within the same framework that defines how QR Code symbols are constructed and read.¹⁰

Barcode verification is the process that measures the quality of a barcode symbol according to ISO/IEC 15416, providing an objective assessment of how well a printed code conforms to defined technical criteria.³ Verification is distinct from mere scanning: whereas a scanner may successfully decode a symbol under favorable conditions, verification evaluates the symbol's inherent quality and its likely performance across a range of readers and environments.³ The parameters assessed during verification include symbol contrast, edge determination, and modulation, each of which contributes to the overall grade assigned to the symbol.³ These measurements help determine whether a barcode will scan reliably in practice, rather than only under ideal laboratory conditions.³

The purpose of barcode verification is to ensure that barcodes meet quality standards for accurate scanning, thereby reducing the risk of read failures at the point of use.³ In environments where each scan must succeed on the first attempt, such as high-volume retail or automated logistics lines, a marginal symbol can cause delays and require manual intervention.³ Verification therefore serves as a preventive quality-control step, applied after printing or marking, to confirm that the symbol's contrast, edge definition, and modulation fall within acceptable limits.³ By identifying substandard symbols before they enter circulation, organizations can avoid the operational costs associated with unscannable codes.³

Barcode verification is important for industries with high traceability requirements, such as healthcare.³ In healthcare settings, where barcodes may be used to identify products, locations, and assets, a failed scan can interrupt critical processes and undermine the integrity of tracking systems.⁴ The use of two-dimensional barcodes such as GS1 DataMatrix in healthcare and other industries further raises the stakes, because these symbols often carry more data and are applied to smaller items where print quality is harder to control.⁴ Verification thus supports the reliability of traceability systems by confirming that each symbol meets the quality thresholds necessary for consistent, accurate scanning.³

Among the many barcode systems in use, GS1 barcodes serve as a foundational tool for identifying products, locations, and assets.⁴ GS1 standards further include barcodes for retail, healthcare, and logistics.⁴ Within these environments, barcodes are used in many applications, including retail, logistics, and healthcare.² The scope extends beyond these fields, as barcodes are now used in many sectors, including healthcare, transportation, and manufacturing.¹ In healthcare specifically, barcode verification is important for industries with high traceability requirements.³ This pattern of use reflects the transition from the earliest retail deployments, where the first barcode scanner was installed in a supermarket in 1974, to a general identification technology.⁵ The result is that identification is no longer confined to consumer goods but reaches assets and locations as well.⁴

Two-dimensional codes have expanded what identification can accomplish. GS1 DataMatrix is a two-dimensional barcode used in healthcare and other industries.⁴ Its two-dimensional nature matters because the QR Code is a two-dimensional code that can be read at high speed.⁸ QR codes can be read by smartphones and dedicated scanners, making them accessible to both consumers and dedicated hardware.⁹ These codes can be used to store URLs, contact information, and text.⁹ They are also applied to mobile payment, product tracking, and digital ticketing.⁹ The QR Code was developed to track automotive parts, showing that the format emerged from industrial tracking needs before spreading further.⁸ Together, these applications demonstrate how a code originally devised for one purpose can support many others.⁹

The modern usage of barcodes and QR codes rests on standardization and verification. Barcode verification measures the quality of a barcode symbol according to ISO/IEC 15416.³ Standards such as GS1 DataMatrix show how a two-dimensional barcode serves healthcare and other industries, while GS1 standards include barcodes for retail, healthcare, and logistics.⁴ Barcodes are used in many applications, including retail, logistics, and healthcare.² QR codes, meanwhile, are used for mobile payment, product tracking, and digital ticketing.⁹ The QR code was standardized as ISO/IEC 18004 in 2000, and that specification is maintained by ISO/IEC JTC 1/SC 31.⁹¹⁰ Barcode verification is important for industries with high traceability requirements, such as healthcare.³ Standardization and verification thus anchor the diverse deployments observed today across sectors.¹⁰