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"Manually key in twenty-six
U.P.C. codes and, on average,
 one of them will be wrong.
Scan them in and you will
get good data from a
quarter of a million
bar codes."




"Simply scanning a bar code
does not verify its readability."




"Ohio University’s Center for
Automatic Identification and
Data Capture offers AIDC help."


Trouble Behind Bars

by Paula Giovannetti

Why use bar codes?  It's pretty simple.  Manually key in twenty-six U.P.C. codes and, on average, one of them will be wrong.  Scan them in and you will get good data from a quarter of a million bar codes.   


Quality bar code printing software and printers have become relatively inexpensive.  Good equipment will pay for itself many times over when it plays a role in producing quality bar code symbols.


Lets look at the components of a bar code printing system, and what to look for when you are producing bad bar codes:


  1. The paper label or the package the bar code is printed on must provide a good background for the bar code.  Bar codes are read based on the difference between the area that reflects the light (usually white) and the area that absorbs the light (usually the black bars). 

    1. Colored labels, especially dark blue or green may not read at all.  The same is true for the color of the bars; red, orange and yellow will not read well.  Tell the graphic designers they can decorate the rest of the box - make the bar codes black and white. 

    2. Don’t buy too many labels at once.  Store the labels in a cool, dry place so the adhesive is not affected, causing the labels to fall off (the hardest label to read is one that is not there).  Labels that are stored in a damp place will absorb moisture and the bar codes will "feather" making them difficult to read. 

    3. Make sure the labels are clean.  If they are dusty, the ink is applied over the dust, which may fall off and cause a “void” or a white spot on what should be a black bar. 

    4. Placing plastic or shrink-wrap over the bar code causes it to reflect light differently, very much like trying to read through water.

    5. This is common sense, but labels that are wrinkled, partially covered or placed around the corner of the box will cause problems.

    6. One of the biggest reasons bar codes do not read well is inadequate “quiet space” on either side of the first and last bar.  The white space that starts and ends each bar code should be at least twice as wide as the widest bar.  It cannot contain graphics or words.


  1. The bar code printer must print crisp, sharp lines.

    1. Verify bar code quality when a ribbon is new and when it is getting worn out.  Many printers track the number of bar codes printed between ribbon changes and may alert you when a ribbon should be replaced.

    2. Just like the labels, the ribbon can get wrinkled if it is not installed properly, and this will cause trouble.

    3. The print head on some printers can burn out or become worn.

    4. Make sure you match the kind of substrate (label or box) you are printing on with the printer.  For instance, thermal printers require special labels.


  1. The bar code itself is made up of data (like the twelve digits put in a U.P.C.), start and stop characters, parity and check digits.

    1. Make sure you are passing the right data to the computer controlling the bar code printer.

    2. Make sure you have selected the correct bar code symbology.  For a U.P.C. you use UPC-A or UPC-E symbology.  For an EAN.UCC-14 often used on an outer carton, you can use Interleave Two of Five (ITF-14) or UCC/EAN-128 symbology. 

    3. A major cause of unreadable bar codes is the size of the bar code itself.  Sometimes companies will try to shrink the bar code or make it larger.  The rule of thumb is to print a bar code that is not less than 80% and not more than 200% of the correct size.  Also, when a bar code is too short (top to bottom) the reader cannot see the bar code properly.

    4. Bar codes that are photocopied can be out of dimension.


Bar Code Verification can save you money

According to Hand Held Products (, a leading supplier of bar code verifiers,  bar code verification requires a special piece of equipment to determine the following characteristics of a bar code:  edge determination, minimum reflectance, symbol contrast, edge contrast, modulation, defects, decode, decodability, quite zones.  That sounds pretty technical but it is worth understanding.  Simply scanning a bar code does not verify it.  A bar code verifier performs precise tests on the bar code to determine if it meets specifications.  Printers today can verify each bar code label as it is printed.  It will cross out a bad bar coded label and print another one.


Independent Third Party Bar Code Verification

You can have your bar code labels verified by BEP Creative Consulting.  Bar Codes will be verified to ISO/ANSI standards and you will receive a report on your bar code label.  The cost for the service is very reasonable - money well spent to get professional, scientific and independent information about your bar codes.  It can help you improve your internal scan rates and help eliminate charges you may be getting from your customers for bad bar codes.


They have designed and developed SCAN – Supply Chain in An eNvelope©, showing UCC-12, EAN-8, EAN-13 and EAN.UCC-14 data structures in a variety of bar code symbologies at the appropriate packaging level.  SCAN can be used to train employees at point of sale devices, picking, packing, shipping or receiving.   SCAN can also be used to test inventory management systems and cash registers to be sure they can process and scan EAN-8 and EAN-13 symbols for the EAN.UCC Sunrise 2005 initiative.  Bruce Philpot can be reached at, or 678-344-7219


Help is Available - Ohio University’s Center for AIDC

Ohio University’s Center for Automatic Identification and Data Capture also offers help.  If you are interested in hiring an AIDC professional, they are a perfect place to find individuals who are well grounded from both a technical and business perspective.  They give a weeklong intensive course in all Automatic Identification technologies – and their business applications – in the annual Automatic Identification and Data Capture Technical Institute (AIDCTI) held each July.  College and university educators, solution providers, end user company representatives, and undergrads receive classroom and hands-on laboratory experience with all of the major AIDC technologies. 


With a well-equipped AIDC lab, professional support staff and faculty, The Center contracts for consulting engagements as well as educational events.  It is the nation’s first university-based, independent and unbiased research and education facility dedicated specifically to the study of automatic identification and data capture.  Its twofold mission encompasses both education and research.  Learn more about the Center for Automatic Identification at




This is an updated, edited excerpt from an article written for the Compliance Advocate.


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