Barcode 128 - Thin-, ThickBar

[KHentschel]

Hello,

i made a Label with a Code 128 Barcode. Our Customer told us that the Bar is to thick and the Gap to small. When i change the Thin-, and Thickbar over Dycodoc nothing is changed. With what parameters i can change here anything?

Thanks for help

Best regards
Klaus

[IDEAL Software Support]

We used numerous barcode scanners to test printed barcodes. All scanners could read them without problems - even the cheapest scanners.

I would like to clarify therefore first, the exact and detailed technical reasons of your customer, which make him claim the bars and gaps have wrong widths.

[KHentschel]

Ich würde Ihnen gerne einen Screenshot des Barcodes zeigen. Das kann ich hier aber nicht anhängen.

Das Messprotokoll der VW AG spricht von folgenden Werten:
Balken: 280 min -213 / max +213
Lücke: -316 min -213 / max +213

[IDEAL Software Support]

The display on the screen (preview) has nothing to do with printing, because the resolution of the screen is too low (except you have a retina or UHD display). This is explained in detail in the help file titled "Programmer's Manual"in the chapter Programming Techniques | 1D Barcodes.

I cite the relevant part here:

Modules and Sizing Barcodes

Modules are the black and white lines. The widths of the thin and thick modules have fixed ratios, for example 1:2. This means, thin lines are half as wide as thick lines.

Since there is a fixed aspect ratio, it is obvious that a barcode needs a fixed amount of space depending on its coding scheme and the number of coded characters. A barcode can not be sized freely! It can only be sized in compliance with the aspect ratio.

Example: a given barcode has 63 modules, 43 thick and 20 thin modules, and shall be painted into a rectangle which has a width of 10 cm.

The VPE barcode library now computes the maximum width of a single module, so that all modules will best fit into the given rectangle, while considering the rule that the thin / thick ratio is 1:2. It can happen then that there are wide gaps at the end of the barcode, because it can not fill the given rectangle. The computations are done on pixel level, so the computation is based on the resolution (in DPI) of the output device. Therefore in some cases (for uneven ratios) the width of a printed barcode might differ between output devices with different resolutions.

The preview displays barcodes always drawn in the full rectangle that was supplied, because when drawing to the preview, the barcode library ignores the ratio rule, otherwise - due to the low resolution of the screen - sometimes a barcode would not be shown at all or only in part.

I do not understand the table you provided:
What does 280 min -213 / max +213 mean? In what units is this? 1/10mm?

Anyway: The aspect ratio of the thin and thick modules is in many cases defined by the barcode specification, and you shouldn't change it. As might become obvious from the explanation of the help file, the solution is to define the rectangular dimensions of the barcode in the right way, so the modules are not stretched too much.