How well a barcode label has been printed will often determine the success of a barcode system. However, it is a factor which is usually neglected. After all, people can read poorly printed text. Why shouldn’t scanners read poorly printed bar code. The difference is people can reconstruct lost data form context. Scanning systems can not.

Allowable printing tolerances are a function of the code chosen and the algorithm used by the reader for decoding. Nearly all bar code formats have well defined specifications. These specifications set the maximum total allowable error before reading breaks down. Errors in printing and scanning must not sum to more than the total allowable error for a chosen coding system. Scanners from different manufactures will often use different algorithms for decoding. These different decoding algorithms will produce different amounts of scanning error.

If one knows exactly what scanners will be used to read the barcode labels, one will know the amount of allowable printing error. But most times one will not know what types of scanners will be used.

If labels will be scanned by unknown scanner types, the barcode labels must be printed by processes with low printing error. That's where the choice of preprinted labels over on-site printing can produce significant savings. With preprinted labels, the supplier monitors and certifies the quality of the symbol. However, if the labels are printed on-site, you must establish a quality control plan. That requires bar code verification equipment, and staff to monitor the label print quality as well as perform maintenance to the printing equipment. But print quality is not the only element which favors preprinted bar code labels for producing a readable bar code symbol.