Making sure your barcodes will work as they should is actually pretty easy, but just because you’ve never had a barcode problem is an illogical and potentially disastrous reason for not taking steps to assure good barcode performance. Here are the most important six steps:
1. Maximize the X dimension. This is the building block unit of the barcode. Making it bigger makes the symbol larger and increases the plus and minus tolerance for bar (in a 1D or linear barcode) or element (in a 2D or matrix symbol) width.
2. Maintain at least minimum quiet zones. More is better and there is no such thing as too much. If you design the quiet zones at their minimum width, bar gain—even within the tolerance—can cause quiet zones to fail. Contrary to popular belief, 2D symbols such as QR Code and Data Matrix code do have quiet zones too.
3. Do not customize QR Codes, but if you must, use an IO compliant verifier to make sure you haven’t customized them to death. While it may be true that a customer is more likely to scan a customized QR Code (I have yet to see any real research that supports this belief), a non-working QR Code will generate awareness—negative awareness—of your brand. Not good.
4. Accurately bar width reduce (BWR) your barcode design file. This is true for 1D and 2D symbols, and should be determined empirically, by testing, not by some so called universal formula for litho or flexo or some other print method. BWR is affected by ink (or thermal transfer ribbon) and substrate, thermal print head temperature, print speed, impression pressure, and a host of other variables. Test to accurately determine bar width reduction and update your tests regularly. Things change.
5. Match the barcode design resolution to the output device resolution. They should be mathematically compatible. The design file must send commands to the printer that it can replicate. A 203 DPI printer has a 1/203=.0049” pixel. If the design file instructs a 203 DPI printer to image an X dimension that is not equal to or an even multiple of .0049”, the printer will interpolate the data and relocate bars and spaces and modify their actual widths. This is true of all digital printers, even very high tech and expensive ones.
6. Do not accept and blithely use barcode files provided by a third party—even your customer. Unless BWR and the other points mentioned above have been taken into account, it is potentially disastrous to use these files. Make them yourself to be confident they are generated appropriately for your printing process. We have seen situations where the pre-press operation has been “standardized”—all the barcodes are as small as possible, BWR is always the same, quiet zones are always to minimum spec. It makes the printer’s job needlessly challenging and puts the barcode performance needlessly at risk.
Here’s a bonus 7th step: always use an ISO compliant verifier to test the printed symbol.
