What is Bar Code Verification?

QUALITY CONTROL FOR BAR CODES!
Verification measures the printed quality of the bar code to international (ISO) standards. This is the standard used by retailers worldwide. According to international standards, verification is mandatory for all companies either designing or printing their own bar codes, ensuring that an acceptable image is created.

Why Verify?
Bar code quality is vital, as every time a bar code fails to scan, costs are incurred. At best the data is required to be input manually whilst at worst deliveries are rejected.
A recent survey by the e-centre (EAN UK) put the cost of poor quality bar codes at over £500 million. Until recently, many retailers have accepted these costs as a ‘fact of trading life’. However, an ever increasing number of major retailers are now taking a very different approach by passing these costs back to suppliers. Goods are returned and fines imposed. For repeat offenders the ultimate sanction can be, and has been, delisting as a supplier.
Insurance
At its most basic level, verification is an insurance policy helping to assure you that your bar code will scan first time at all levels in the supply chain, thus enhancing your supplier/customer relationship.
But it’s more than that. As part of an effective QA system it can help you win business. Are your competitors using verification? Are they questioning the quality of your bar codes with your customers? Is it affecting your business?
Why Can’t I Just Use A Scanner?
Scanning is no substitute for verification as no two bar code readers are identical. They vary from wands to lasers to cameras, from manually operated to automatic. Ambient light will vary as will the distance of scanning. A bar code that is ‘checked’ with a wand gives no guarantee that it will be readable with another wand, let alone a laser based unit.
A verifier is a scientific device, taking precise measurements of each individual bar and space and the amount of light reflected from each. More advanced units will automatically identify the symbology and magnification, check data structure and validate the content as well as providing diagnostic information. It is all very well knowing that your bar code is incorrect but a verifier must be able to identify the problem to allow you to take the necessary corrective action.
Why was the ISO/CEN/ANSI method introduced?
Prior to the Current ISO standard of verifying printed bar code symbols, only two factors were taken into consideration:
• Dimensional accuracy of the bars and spaces.
• Reflectance values of the bars and the background (PCS).
This traditional method would have been a reasonable way of assessing the print quality, except that there was no agreed way of determining where bar edges actually were or how and where reflectance measurements should be made. As well as this, bar codes were being measured with differing beams of light (apertures). Both of these factors resulted in a wide variation of results between verifiers.
With the variety of uses for bar codes and the wide range of printing techniques used, it was felt that a more scientific approach was needed. In particular it was noted that different scanners and the differing environments in which these were used resulted in some aspects of poor print quality being more significant than others. Simple reflectance measurements were also found not to be helpful when the contrast might vary within the symbol. A definition of where a bar-space transition actually occurred was required as were specific aperture sizes dependent upon the symbology and size of bar code.