Verifier Grade: How does it relate to scanning?
What does it mean that the verifier grade on your latest labels is a C? Does this guarantee that your barcode will work everywhere it goes?
Does an “A” Verifier Grade guarantee scannability?
It’s a knotty question and the simple answer is, “No, none of the ANSI grades come with any sort of ‘guarantee’ of any sort.” Even a symbol with an A grade will not necessarily perform flawlessly in every scanning situation.
The verifier grade is a guideline, a method for predicting scanning success in an ever-broadening sea of scanning technologies with different optics, different data capture technologies, different electronics and firmware—and all of them aging and operated with varying degrees of rough handling, all in different environments.
The unit of measure for the verifier grade protocol is one scan, AKA “first read rate”. A symbol with an A grade will generally scan successfully on the first try. The nine parameters defined by the ISO Specification 15416-1 are what define symbol quality.
Symbols achieving a B grade will not be as high quality as A grade symbols; one or more of the ISO 15416-1 parameters have been downgraded to a B. B grade symbols will likely need to be rescanned to be decoded successfully.
C grade symbols will need to be rescanned even more than B grade symbols. Rescanning means redundant scanning on the same symbol, and more frequent need to rescan different examples of the same symbol: it is important to understand that the performance of a single barcode does not define the quality of an entire print run.
Verifier Grade is an attempt to predict first read rate
A symbol with a grade D will require multiple scans in different parts of the barcode to decode successfully. When users anticipate this grade level, such as with barcodes printed on corrugated, scanners should be intentionally selected that perform best in that application.
F grade symbols are unlikely to scan successfully in most scanning environments. I have often been asked been verifier users if their F grade barcodes are acceptable because the verifier was able to decode them. The significant thing for verification is the grade—not the decode. Verifiers and scanners differ in this regard.
The verification process should never be “optimized”. I once visited a printing operation where the quality person thought his job was to test and retest his samples until the verifier produced an acceptable grade. Furthermore, the test samples should always be in their “final form” exactly as they are ultimately presented to the end-user’s scanner. If they shrink wrapped in final form, they should be shrink wrapped when verified. If they are inserted into a plastic case, they should be verified in the plastic case. If they are on a translucent plastic bottle with green liquid inside, they should be verified accordingly.
Verifier Grade should be taken from the symbol in its final form
Finally, make sure the verifier is compliant to the ANSI/ISO specification—it is meaningless to use a quality testing tool with an unknown performance benchmark. For the same reason, make sure the verifier has been recently calibrated.
