The most important implementation resource for bar code identification are the over 100 GS1 Member Organisations in countries all around the world. This page takes new bar code users through the basic steps they must take to begin using bar codes.
Ten Steps to Bar Code Implementation
- Step 1: Get a GS1 Company Prefix
- Step 2: Assign 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 Color
- Step 9: Pick the Bar Code Placement
- Step 10: Build a Bar Code Quality Plan
Before a company can begin using bar codes, they must create the numbers that go inside the bar code. These numbers are called GS1 Identification Keys. The first step in building a GS1 Key is to obtain a GS1 Company Prefix from a GS1 Member Organisation. GS1 Company Prefixes are used by over 1 million companies worldwide as the basis for creating unique numbers to identify everything in the supply chain. To obtain a GS1 Company Prefix contact the GS1 Member Organisation in your country.
After receiving a GS1 Company Prefix, a 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. You learn about how to format each number then use the GS1 Company Prefix in combination with reference numbers you assign. Your local GS1 Member Organisation can provide you with specific information about how many numbers you can assign based on the length of your GS1 Company Prefix.
To begin, you should decide what you are bar coding and if the bar code will carry static or dynamic information inside it. An example of static information would be simply a product identification number (GTIN) on a cereal box. An example of dynamnic information would be printing 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 like a laser printer in your office or thermal transfer printer in your warehouse.
Knowing how you will print your bar code is an important question to answer in developing a good bar code implementation plan. Again, your local GS1 Member Organisation is there to assist you in making the right selection and many Member Organisations can also help you find a printer in your local area.
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 a general distribution
- Product package scanned at POS but also scanned in distribution
- special environments like medical device marking
By knowing where your bar code will be scanned you can establish the right specifications for its production. For example, if a product package is scanned at Point-of-Sale (POS) and in general distribution, you will need to use an EAN/UPC symbol to accomodate POS but print it in a larger size to accomodate distribution scanning and ensure the placement meets automated distribution scanning requirements.
You can find more information in the GS1 General Specifications (available from your local GS1 Member Organisation, for on scanner environments see Section 5.4, for symbol placement consult Section 6.0).
Selecting the right bar code is critical to the success of your bar code implementation plan, but here are some high level tips:
- If you bar code a trade item that will be scanned at the retail point-of-sale (POS), you must use an EAN/UPC symbol.
- If you are printing a bar code with variable information like serial numbers, expiry dates, or measures, then you will use GS1-128, GS1 DataBar (RSS), or in special cases Composite Component or GS1 DataMatrix symbols.
- If you want to encode a URL into a bar code to make available extended packaging information to the end consumer, then the GS1 QR Code is the symbol you should use.
- If you just want to print a bar code carrying GTIN on a corrugated carton, ITF-14 may be the choice for you.
There are other factors to consider so contact your local GS1 Member Organisation to see what implementation products and services they offer.
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 on the symbol specified, where the symbol will be used, and how the symbol will be printed.
EAN/UPC Symbols differ from ITF-14 and GS1-128 Symbols because they are scanned by retail omni-directional scanners. This means that EAN/UPC Symbols have a fixed relationship between symbol height and width. When one dimension is modified, the other dimension should be altered by a proportional amount.
Because of this relationship, EAN/UPC Symbols have a nominal height and width specified. 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 of sizes 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 in Figure 1.3.1-1.
In order to decrease the amount of space EAN/UPC Symbols take up on a design, a decreased symbol height might be specified. This process, called truncation, is not permitted within EAN/UPC Symbology specifications and should be avoided. This is 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 184.108.40.206 (available from your local GS1 Member Organisation).
When EAN/UPC Symbols are used in logistics (shipping and distribution) as well as at the Point-of-Sale (POS), the range of magnification allowed is limited to between 150% and 200%. An example of this would be the symbol on a carton used for a large appliance (e.g. TV or microwave oven).
ITF-14 and GS1-128 Symbols
ITF-14 and GS1-128 Symbols also have a range of sizes specified. 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 the application where they are used or the identification number they carry in GS1 General Specifications, Section 5.4.2 (available from your local GS1 Member Organisation).
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.
As always, be sure to contact your local GS1 Member Organisation for additional implementation guidance.
The text beneath a bar code is important because if the bar code is damaged or of poor quality to begin with, then the text is used as a back-up. Click here for some examples of text formatting.
The best way to cover questions about the Human Readable Interpretation for GS1 System Bar Code Symbols is to answer some of the more frequently asked ones.
Does the Human Readable Interpretation need to be a certain size?
The OCR-B font was originally specified for use with EAN/UPC Symbols, but GS1 System specifications now permit any font as long as it is clearly legible. For detailed size specifications for EAN/UPC Symbols, see GS1 General Specifications Section 5.1, Appendix 6 (available from your local GS1 Member Organisation).
The human-readable text for ITF-14 and GS1-128 Symbols must be clearly legible and in a size proportional to the symbol size as per GS1 General Specifications Section 220.127.116.11 (ITF-14) and Section 18.104.22.168 (GS1-128) (available from your local GS1 Member Organisation).
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 as per GS1 General Specifications Section 22.214.171.124 (ITF-14) and Section 126.96.36.199 (GS1-128) (available from your local GS1 Member Organisation).
Is the layout of the human readable characters under the bar code important?
Yes. For EAN/UPC Symbols the human readable characters should be as the drawings referenced in the question above. The spacing of Human Readable Interpretation characters under ITF-14 and GS1-128 helps make the text easier to read and key enter. 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 and are they encoded in the bars and spaces of the symbol?
All AIs must be enclosed in parentheses in the Human Readable Interpretation, but the parentheses are not encoded in the symbol per the GS1 General Specifications Section 188.8.131.52. (available from your local GS1 Member Organisation).
How many digits do I print beneath the EAN/UPC Symbol in the Human Readable text?
You must, absolutely and without exception, print 12 digits, no more, no less, below the UPC-A Symbol.
You must, absolutely and without exception, print 13 digits, no more, no less, below the EAN-13 Symbol.
You must, absolutely and without exception, print eight digits, no more, no less, below UPC-E and EAN-8 Symbols.
The optimum color combination for a bar code symbol is black bars with a white background (spaces and Quiet Zones). If you want to use other colors, the following may help you in choosing satisfactory ones:
- GS1 Bar Code Symbols require dark colors for bars (e.g., black, dark blue, dark brown, or dark green).
- The bars should always consist of a single line color and should never be printed by multiple imaging tools (e.g., plate, screen, cylinder).
- GS1 Bar Code Symbols require light backgrounds for the Quiet Zones and spaces (e.g., white).
- In addition to light backgrounds, ""reddish"" colors may also be used. If you have ever been in a darkroom with red lighting and tried to read red copy, you know it can virtually disappear. This is also true of similar colors such as orange, pink, peach, and light yellows. Given the fact that most bar code scanners use a red light source, you can quickly see why these colors may be suitable for backgrounds, but should be avoided for bars.
- In many cases the symbol background is not printed. It is the color of the substrate that is being printed. If the symbol background is printed beneath the bars, the background should be printed as solid line colors.
- If you use multiple layers of ink to increase the background opacity, each layer should be printed as a solid.
- If you use a fine screen to deliver more ink to the substrate, be sure there are no voids in the print caused by the screen not adequately filling in.
Again, by staying with black bars and white spaces, you have selected the optimal combination, but other color combinations can be used. Consult an experienced printer recommended by your GS1 Member Organisation for additional guidance.
When discussing symbol location we are referring to the symbol placement on the design. When assigning symbol placement the packaging process should be considered. You should consult the packaging engineer to make sure 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 (available from your local GS1 Member Organisation):
- Logistics Label Design, Section 184.108.40.206
- 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, the printing company should be consulted before assigning the symbol rotation. This is because many printing processes require bar codes to 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 for the plate roll circumference.
When using either silk screen or rotogravure printing processes, the symbol should be aligned parallel to the cell structure on the screen or gravure plate cylinder to provide the smoothest bar edge possible.
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 way a scanner does, but goes further by grading the symbol's quality.
GS1 utilises 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, or what identification number it is carrying. 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 220.127.116.11 (available from your local GS1 Member Organisation) provides a quick reference list of symbol quality specifications depending on the symbol type, the application, or the identification number the symbol is carrying.
GS1 members may choose to perform their own quality control of bar code production but today many GS1 Member Organisation offer bar code quality verification services.