10 Steps to Bar Code Implementation

To begin using bar codes, perform the following basic steps:

• Step 1: Get a Company Prefix Licence from GS1 Canada
• Step 2: Assign Identification Numbers
• Step 3: Select a Bar Code Printing Method
• Step 4: Select a Primary Scanning Environment
• Step 5: Select a Bar Code
• Step 6: Pick a Bar Code Size
• Step 7: Format the Bar Code Text
• Step 8: Pick a Bar Code Colour
• Step 9: Pick the Bar Code Placement
• Step 10: Build a Bar Code Quality Plan

The GS1 General Specifications, referenced throughout the 10 steps, are available at GS1 Canada offices and www.gs1ca.org for GS1 Canada members.

To learn more about bar code implementation around the world, please refer to the GS1 Global Office website.

Step 1: Get a Company Prefix Licence from GS1 Canada

Before your company can begin using bar codes, you must create the numbers that will be represented by the bar code. These numbers are called GS1 Identification keys. The first step in building a GS1 Key is to obtain a Company Prefix Licence from GS1 Canada. Company Prefix Licences are used to identify over 1 million companies and form the foundation for the unique identification of everything in the supply chain. To register a Company Prefix Licence with GS1 Canada, you must become a member.

To learn about GS1 Canada membership, click here.

Step 2: Assign Identification Numbers

After receiving a Company Prefix Licence from GS1 Canada, your company is ready to begin assigning identification numbers to their trade items (products or services), themselves (as a legal entity), locations, logistic units, individual company assets, returnable assets (returnable pallets, kegs, tubs) and service relationships.

The process is fairly simple, as GS1 Canada will provide you with resources on how to format each GS1 identification number and use the Company Prefix Licence in combination with the reference numbers you assign. The length of your Company Prefix Licence determines the number of identification numbers to assign.

Step 3: Select a Bar Code Printing Company

To begin, you should decide which items you are bar coding and whether the bar code will carry static or dynamic information. For example, static information may include a product identification number, or Global Trade Item Number (GTIN), on a cereal box. Dynamic information may include serial numbers on product labels. 

If your bar code has static information and you need a large volume of labels, then you will likely ask a printing company to print your labels. If you need a small volume of labels or need to print labels with dynamic information, you will likely need an on-demand printer, such as a laser printer in your office or thermal transfer printer in your warehouse.  

Knowing how you will print your bar code is important in developing a good bar code implementation plan. A list of solution providers is available in the members-only section of our website.

Step 4: Select a Primary Scanning Environment

The specifications for bar code type, size, placement, and quality all depend on where the bar code will be scanned.

There are four basic scanner environment scenarios for trade items:

• Product package scanned at the retail point-of-sale (POS)
• Product package scanned in general distribution
• Product package scanned at POS and in distribution
• Special environments, including medical device marking

By knowing where your bar code will be scanned, you can determine which specifications apply to its production. For example, if a product package is scanned at POS and in general distribution, you will need to use an EAN/UPC symbol to accommodate POS, print it in a larger size to accommodate distribution scanning and ensure that the placement meets automated distribution scanning requirements.

The GS1 General Specifications provide additional information.

Step 5: Select a Bar Code

Selecting the right type of bar code is critical to the success of your bar code implementation plan. Use these important tips when selecting your bar codes:

• If your trade item will be scanned at retail POS, use an EAN/UPC bar code symbol
• If you are printing a bar code with variable information, such as serial numbers, expiry dates or measures, use GS1-128, GS1 DataBar™ (RSS) or, in special cases, Composite Component or GS1 DataMatrix symbols

If you just want to print a bar code carrying a GTIN on a corrugated carton, an ITF-14 may work best.

Step 6: Pick a Bar Code Size

After the correct bar code symbol is specified together with the information to encode in it, the design stage begins. The size of the symbol within the design will depend upon the symbol specified, where the symbol will be used, and how the symbol will be printed.

EAN/UPC Symbols
EAN/UPC symbols differ from ITF-14 and GS1-128 symbols, as they are scanned by retail omni-directional scanners and have a fixed relationship between symbol height and width. When one dimension is modified, the other dimension must also be altered by a proportional amount.

Due to this direct relationship, EAN/UPC symbols have nominal height and width specifications. A range of allowable sizes from 80% to 200% of the nominal size are also specified and a figure showing the range of dimensions can be found in GS1 General Specifications Section 5.1, Appendix 7. This range is often referred to as "magnification factors" on purchase orders specifying EAN/UPC symbol sizes. The minimum, nominal and maximum magnification for EAN/UPC symbols are shown below.

EAN/UPC Magnification

Minimum (80%)


Nominal (100%)

Maximum (200%)


To decrease the required amount of space for an EAN/UPC symbol on a design, a decreased symbol height might be specified. This process, called truncation, is not permitted within EAN/UPC Symbology specifications. It should be avoided because of the negative impact it has on scan rates for retail omni-directional scanners. For more information on truncation, refer to the GS1 General Specifications, Section 6.3.3.4.

When EAN/UPC symbols are used in logistics (shipping and distribution) as well as at POS, the range of magnification allowed is limited to between 150% and 200%. For example, this symbol is used on a carton used for a large appliance, such as a TV or microwave oven.

ITF-14 and GS1-128 Symbols

A range of sizes is also specified for ITF-14 and GS1-128 symbols. ITF-14 and GS1-128 symbol sizes are often specified by the width of the X-Dimension instead of magnification values. You can find information on the sizes for ITF-14 and GS1-128 symbols based on their application or the identification number they carry in the GS1 General Specifications, Section 5.4.2.

Consideration of the Printing Process

The final major consideration for symbol size is the capability of the selected printing process. The minimum size (magnification) and correct Bar Width Reduction (BWR) for a symbol varies by printing process and even from press to press. Printing companies should establish a minimum symbol size (magnification) and BWR to achieve acceptable and repeatable quality results.

Step 7: Format the Bar Code Text

The text, or human-readable interpretation, beneath a bar code is important, as it acts as a back-up if the bar code is damaged or of poor quality. The following Frequently Asked Questions will familiarize you with the necessary requirements for GS1 bar code symbols.

Does the Human-Readable Interpretation need to be a certain size?

The GS1 System specifications now permit any font, as long as it is clearly legible. For size specifications for EAN/UPC symbols, see GS1 General Specifications, Section 5.1, Appendix 6.

The human-readable text for ITF-14 and GS1-128 symbols must be clearly legible and proportional to the symbol size in accordance with GS1 General Specifications, Sections 5.2.1.6 (ITF-14) and 5.3.7.4 (GS1-128).

Is the Human-Readable Interpretation supposed to be above or below the symbol?

It depends on the symbol you are using. For EAN/UPC symbols, refer to the drawings in the GS1 General Specifications, Section 5.1, Appendix 6. For ITF-14 and GS1-128 symbols the text can be printed above or below the symbol in accordance with GS1 General Specifications, Section 5.2.1.6 (ITF-14) and Section 5.3.7.4 (GS1-128).

Is the layout of the human-readable characters under the bar code important?

Yes. For EAN/UPC symbols, the human-readable characters should be represented as in the drawings referenced in the question above. The spacing of Human-Readable Interpretation characters under ITF-14 and GS1-128 makes the text easier to read and key in. While including spaces is perfectly appropriate for the Human-Readable Interpretation, the spaces must not be encoded in GS1 symbols.

I see parentheses around the Application Identifiers (AI) in the GS1-128 symbol. Are they supposed to be there? Are they encoded in the bars and spaces of the symbol?

All AIs must be enclosed in parentheses in the Human-Readable Interpretation in accordance with GS1 General Specifications, Section 5.3.7.4. However, the parentheses are not encoded in the symbol.

How many digits do I print beneath the EAN/UPC symbol in the Human-Readable text?

Without exception, you must print exactly:

• 12 digits below the UPC-A bar code symbol
• 13 digits below the EAN-13 bar code symbol
• 8 digits below UPC-E and EAN-8 bar code symbols.

Step 8: Pick a Bar Code Colour

The optimal colour combination for a bar code symbol is black bars with a white background (spaces and Quiet Zones).

If you want to use other colours, the following information will assist you:

• GS1 bar code symbols require dark colours for bars (e.g., black, dark blue, dark brown, or dark green)
• Bars should always consist of a single line colour and should never be printed by multiple imaging tools (e.g., plate, screen, cylinder)
• GS1 bar code symbols require light (i.e. white) backgrounds for Quiet Zones and spaces
• “Reddish" colours may also be used as backgrounds. If you have ever been in a darkroom with red lighting and tried to read red copy, you know it can virtually disappear. The same is true of such colours as orange, pink, peach and light yellows. Since most bar code scanners use a red light source, red may be suitable for backgrounds, but should be avoided for bars
• Often the colour of the substrate – rather than the symbol background -- is printed. If the symbol background is printed beneath the bars, the background should be printed as solid line colours
• If you use multiple layers of ink to increase the background opacity, each layer should be printed as a solid line
• If you use a fine screen to deliver more ink to the substrate, ensure there are no voids in the print caused by the screen not adequately filling it in.

GS1 Canada can help you identify a solution provider who can assist you in making the right selection and/or print your bar codes. A list of solution providers is available in the members-only section of GS1 Canada’s website.

Step 9: Pick the Bar Code Placement

Symbol location refers to where the symbol is placed on the package design. When assigning symbol placement, the packaging process should be considered. Consult the packaging engineer to ensure that the symbol will not be obscured or damaged (e.g., over a carton edge, beneath a carton fold, beneath a package flap or covered by another packaging layer). To determine the proper location for GS1 bar codes, see the following sections of the GS1 General Specifications:  

• Logistics Label Design, Section 2.2.4.4
• General Placement Principles, Section 6.2
• General Placement Guidelines for the Retail Point of Sale, Section 6.3
• Placement Guidelines for Specific Package Types, Section 6.4
• Symbol Placement for Clothing and Fashion Accessories, Section 6.5
• General Format Guidelines for Clothing and Fashion Accessories Labels, Section 6.6
• General Placement Guidelines for Symbol Placement on Items Used in Distribution, Section 6.7

After determining the proper placement, consult your printing company before assigning the symbol rotation because many printing processes require that bar codes be printed in a specific orientation to the feed direction of the web or sheet.

If possible, when using flexographic printing, the bars should run parallel to the press web direction or in the picket fence orientation. If the bars are required to run perpendicular to the press direction or in the ladder orientation, try to avoid distorting the symbol on the plate roll circumference.

When using either silkscreen or rotogravure printing processes, the symbol should be parallel to the cell structure on the screen or gravure plate cylinder to provide the smoothest bar edge possible.

Step 10: Build a Bar Code Quality Plan

ISO/IEC 15416 Bar Code Print Quality Test Specifications for Linear Symbols describes a method for assessing the quality of bar code symbols after they are printed. An ISO-based verifier looks at the symbol in the same way that a scanner does, but goes further by grading the symbol's quality.

GS1 utilizes the ISO/IEC method but specifies the minimum grade necessary for every GS1 bar code based on which symbol is used, where it is used and which identification number it carries. In addition to the minimum grade, GS1 also specifies the verifier aperture width and wavelength.

Setting up different minimum specifications is similar to a university using a standardized test to determine whether applicants qualify for admission. Several universities may utilize the same standardized test, but each sets the minimum score necessary for its applicants to be admitted.

GS1 General Specifications, Section 5.4.2.8 provides a list of symbol quality specifications, depending on the symbol type, application or identification number the symbol carries.

GS1 members may choose to perform their own quality control of bar code production. To learn about GS1 Canada’s Bar Code Scan Verification service, click here.