Printing barcodes is a very tricky task. Even on high resolution devices, rounding errors can heavily decrease the legibility of barcodes. A typical bar width for a barcode is in the range of 0.5 mm. On a 600 dpi device (actual pixel density 609,6), this corresponds to just 11-12 pixels. If you're working in absolute coordinates you'll end up with a bar code that has bars between 0.45 and 0.55 mm (approximately +-1 pixel error). While this barcode may still be legible, its usability under heavy load in high performance environments will be quite restricted.
To get a reliable grade for barcode quality, barcodes are verified according to ISO/IEC 15416 (see http://en.wikipedia.org/wiki/Barcode#Quality_control_and_verification), receiving a grade between F (worst) and A (best). Often, a grading result of at least B is required by barcode consumers. The verification process includes the recording of a "Scan Reflectance Profile" and the thorough analysis of this scan, including a number of parameters such as Decodeability, Modulation etc.
Starting with version 20, most List & Label barcodes offer a Property "Printing Optimization". If set to true, the barcode pixels will be aligned to the device pixels at print time. Rounding errors cannot occur any more and the typical grading result is "A" or "B" depending on the printer and paper quality.
Another improvement is the introduction of a bar width reduction parameter. Especially ink jet printers (albeit some laser printers, too) "overprint" their dots slightly depending on paper quality and other physical parameters. The bar width reduction property allows to take this effect into account and reduces bar widths by the given amount of pixels. This way, the printing result can be optimized exactly for the used hardware.
Valid from List & Label 20
IDKBTE000875 KBTE000875