Barcode Image Generation

If you decide to generate the barcode image yourself…

The size of the barcode - the EAN/UPC symbology family

The barcode is read by the laser light beam of a scanner. To read EAN/UPC bar code successfully, laser light beam must be placed across ALL bars. In-built software application receives and uses EAN-13 bar code data for calculation of 13 check digit on the basis of preceding 12 digits. If a computer-generated check digit is equal to the 13 check digit of the scanned bar code, the scanner beeps confirming success of a reading.

If dimensions or location/placement of the barcode are not correct, the laser light beam can’t sweep all bars when reading the barcode. If check digit on the label is not correct, the barcode could not be read also. That is why close attention should be paid to both height of the bars and correct calculation of the check digit.

In practice quality of the printed barcode is checked by a simple rule: a fixed reader must read barcode from the FIRST attempt.

Fixed scanners use a variety of beam sweeps for ease reading of barcodes and for lighting up a scanning zone scanners use an array of lights but not a single spot of light.

EAN/UPC symbols are reflected as a light box. There are bars inside the light box. It is necessary to provide “window” of relevant size when labeling. It is not reasonable to think of aesthetics and to artificially truncate dimensions of barcode. It is better to place EAN code at other location, separately from the main label, but not to deviate from the standard ranges of sizes for barcodes.

MODULO are used to represent dimensions of a symbol in the standard ranges of sizes for barcode. MODULO is unit of measurement of all characters of the bar code, i.e. bars and spaces (their width may vary from 1 to 4 modulo). If a scale of magnification is changed, a dimension of modulo in mm is also changed. For the standard range of sizes for a barcode (magnification factor 1,0), the width of the modulo 1X=0,33 mm. The width of the narrowest modulo in a barcode symbol could not be more than one modulo. For convenience all sizes referred below are in mm, but not in modulo (as in the text of a standard):


  • width of a symbol - 37,29 mm
  • height of a symbol - 25,93 mm
  • height of a bar - 22,85 mm
  • left clear area (quiet zone) - 3,63 mm (or 11Х)
  • right clear area (quiet zone) - 2,31 mm (or 7Х)
  • bars that are formed left and right stop characters, and also, middle stop character must be extended DOWNWARDS for 1,65 mm (or 5X)
  • height of a digits in the nominal dimensions of a symbol - 2,75 mm
  • minimum distance from the upper edge of the digits to the lower edge of the bars - 0,5Х (0,165 mm)

It is acceptable to proportionally magnify of EAN-13 symbol to 200% of the nominal dimensions and also, to decrease of EAN-13 symbol to 80% of the nominal dimensions:

  • The nominal dimensions (with quiet zones): 37,29 mm х 25,93 mm (100%)
  • The nominal dimensions (with quiet zones): 37,29 mm х 25,93 mm (100%)
  • The nominal dimensions (with quiet zones): 37,29 mm х 25,93 mm (100%)

Many readers must have seen “nice” barcodes which are look like narrow and extended ladder. To achieve such “a nicety” manufacturers of labels heavily truncate the height of the barcode’s symbols and do not change the horizontal dimensions. It is not acceptable to truncate the height of a barcode! Reducing the height of symbol and keeping its horizontal dimensions will prevent normal operation of multi-directional scanners which are widely used in the supermarkets.