Barcode is a graphical presentation of information. The information is encoded with dark and light stripes, determined by symbolism-specific code. Barcode is designed for e-readers, additionally usually under the code there is placed the text representation of what was contained in the code. It is designed to allow manual entry of code where the reader will not be able to read the information.

Barcode found the widest application in trade. The main use of the bar code is the automatic identification of products, which allows much faster, for example customer service at cash registers. Nowadays it is practically impossible to find in store merchandise that hasn't got a bar code assigned. If the shop gets merchandise that does not have an official barcode, the shop assigns custom barcode to it. Even companies associated with the transport couldn't resist the popularity of barcode: every parcel, pallet is labeled with a barcode.

A key element that determines whether barcode fulfills its primary task is print quality. The print quality is dependent on the nature of the ground and from techniques of reproduction. Main reproduction problems: spreading of the paint, poor fixation of paint, too low contrast between the color of the substrate and the color bars.

For barcodes EAN-8, EAN-13, UPC-A, UPC-E, ISBN, ISSN in GS1 specification we can read: „For digits 1, 2, 7, 8 the bars and spaces are reduced or enlarged by one-thirteenth of a module width to provide a uniform distribution of bar width tolerances and thus improve scanning reliability.”
Barcode generators EAN-8, EAN-13, UPC-A, UPC-E, ISBN, ISSN support this option.

 

One of the most common problems during reproduction is an increase in the thickness of the bar. Each of the generators have the capability to reduce the width of the line. This allows the generation of such a code, which after being printed will have the correct width of the bar. That increases your chances of reading the code by the reader. For barcodes EAN-8, EAN-13, UPC-A, UPC-E, ISBN, ISSN nominal bar width is 0.33 mm. Using the bar width reduction must not lead to a situation where the thinnest bar will be less than 0.13 mm in the printing form. If this happens, use a higher zoom ratio to (0.33 mm × magnification factor) - REDUCE WIDTH ≥ 0.13 mm.

For barcodes EAN-8, EAN-13, UPC-A, UPC-E, ISBN, ISSN it is recommended to use Coefficient of magnification in the range of 80% to 200% of the nominal size. Each of the generators allows you to enter the zoom ratio in this range.

Recommended zoom factors:

The most frequently used bar code readers are equipped with red light - 630 nm wavelength. Symbols are correctly read only if the prints with the printed code, lines dimensions, have got right overprint contrast. Obtaining the contrast is dependent on both the background color and the color bars. The background should as bright as possible and the lines should be at their darkest. Background color should be: white, yellow, orange or bright red, and lines: black, blue, green and dark brown.

When reproducing the barcode accuracy of output devices must be considered. Inkjet printer running at a resolution of 600 dpi is accurate to 0.0423 mm. So if we print on the 0.33 mm bar we may receive a dash with a thickness from 0.2961 mm to 0.3384 mm. An imagesetter, which is used to perform printing forms works usually with a resolution of 2540 dpi, gives the accuracy of 0.01 mm. In this case, the bar width is between 0.32 mm and 0.34 mm.

The vast majority of industrial printers has resolution 203.2 dpi (8 dpm). This means that the printer has a precision of 0.125 mm. We can print lines, eg: 0.125 mm, 0.250 mm, 0.375 mm (line thickness is a multiple of 0.125 mm). Industrial printers at higher resolutions are also available: 304.8 dpi (12 dpm), giving an accuracy of 0.0833 mm or even 609.6 dpi (24 dpm), giving an accuracy of 0.0416 mm. Most programmers who first encountered an industrial printer were trying to treat it like a regular office printer. This approach results in poor print quality, as there is no proper easy way to control the printout (barcode parameters) of the generated barcode when programmers use software like CrystalReport or FastReport or when trying to print to this printer using a driver provided to the system. By printing in this way we always get better results for office printing than for an industrial printer. Printing on such a printer boils down to writing a program and sending it to it. The most popular industrial printer programming languages ​​are: DPL, EPL, ZPL, Basic, J-Script. Typically, all industrial printers have features that allow you to print codes. Using these features gives the best results: the code is very clear, readable, and does not cause problems when trying to read by any barcode reader. Any attempt to print codes otherwise fails (the quality of the printed code is far from expected).