Bar Width Reduction

Bar Width Reduction (or BWR) is adjusting the barcode bars thickness to compensate for ink spread when printing.

Say if you draw with a marker pen on a very soft paper the ink will most likely spread and the line will become wider — the same might happen when you print, just not at that extent.

Ink spread, or “dot gain” or “press gain” may increase the width of the bars of the barcode and make it more difficult to scan. This is more common for traditional printing press, rather than office printers, but it is not just about printers. It also depends on ink, the substrate, the condition of the press, the room temperature and much more.

In order to avoid the scanning problems, you might need to compensate the ink spread by making the bars a little narrower, so they come to the normal thickness after printing and ink spreading.

Measuring the Bars

Although some shops and printers provide the bar reduction width, the best way to get the right number is to measure it yourself.

Start with no width adjustment and make a test print with the ink and paper you are going to use. Then measure the width of the printed bar and compare it with the reference with in the source file. The difference is what you need to compensate.

Adjusting the Bars Width

Say you printed a barcode, measured the bar and found out that the printed bar is 0.01 mm wider than the reference one. This means you need to make all the bars 0.01 mm narrower in order to compensate the press gain.

You can do this on the Appearance panel of our Barcode software, there is a special Bar width adjustment field there:

Bar width reduction parameter in Barcode

The reason it is called “adjustment” instead of “reduction” is to avoid the ambiguity of the latter. Adjustment clearly tells if we make the bars wider (positive values) or narrower (negative values), while reduction does the opposite which is not always intuitive.

So as the printed bars are 0.01 mm wider than we need, we should use -0.01mm width adjustment to compensate that:

Adjusting bar width reduction in Barcode

The bars became a little thinner. It is barely visible to the naked eye, but if you reduce them even further, you will clearly see the effect:

Reducing the bar width a little bit more to show the effect

The bars became much thinner and that’s exactly what the bar width adjustment does.

Notes

Here are some side notes that might be helpful:

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