Checking Verification
Reading a barcode successfully on your own scanner doesn't guarantee it will work everywhere else — verification is the formal process that confirms a printed barcode truly meets the tolerances of its symbology.
We are bar coding our products and some customers are having trouble reading the codes, although they read successfully with our reader. We are told we need to verify the codes — what does this mean?
Requirements for checking and verifying bar codes vary depending on how the printed codes will be used. If you are printing bar codes purely for internal use, with no requirement for anyone outside your company or organization to read them ("closed" systems), then simply confirming that the bar code encodes the correct characters and can be read by your chosen equipment may well be perfectly adequate.
However, if you are producing bar codes for use by third parties — potentially on a variety of unknown readers and scanners ("open" systems) — you may need to go a step further. This is particularly true in retail, where some large store chains impose penalties on suppliers who provide goods with unreadable codes. In these cases, the requirement is to verify that the bar code was printed in line with the "rules" of the symbology being used, and that its print quality meets specification.
Verification is a more complex process than simple checking. It requires specialized equipment capable of scanning your bar code and analyzing its compliance against the rules of the symbology. Typically this means purchasing a dedicated bar code "verifier." Verifiers can report a wealth of technical detail about a bar code — contrast ratio, wide/narrow bar ratio, and more — and will usually summarize these measurements to indicate whether the code falls within or outside the acceptable tolerance range for its symbology. Sometimes this is condensed even further into a simple "good" or "bad" result.
Checking and verifying printed bar codes are not the same thing, and it's important to understand the difference. Successfully reading a code with a given reader does not guarantee that the bar code is correctly printed and readable by every scanner operating within acceptable tolerances. That said, the added cost of verification may be prohibitive for some businesses, and if you're confident in the quality of your printing source, simple checking may be sufficient. Just be prepared for the day someone says "we can't read your bar codes" — pointing out that they work fine on your own reader isn't the same as having properly verified them.