Barcode Scanning
When printing barcodes to a printer of less than 600 DPI (Dots Per Inch), the printer may not accurately reproduce the exact bar and space ratios. This can result in a read error on the barcode scanner or verifier.
As a general rule the font size on printers with less than 600 DPI should be no smaller than 20 points. However, the optimal font point size will depend on the type of barcode font being printed. Because an exact number of dots is required to create the exact ratio of bar and space sequences, the optimal point sizes for a particular font are oftentimes according to a particular multiple. For example, to properly print Code 128 fonts to a Zebra Thermal 203 DPI printer, the assigned point size should be a multiple of 6 (6, 12, 18, 24, 30, etc.). The chart below presents a number of standard barcode font types, along with the font sizes that will yield the best results on the two types of sub-600 DPI printer.
NoteIf a company’s software does not support printing at the specified point sizes in the chart, then barcodes must be printed at a point size larger than 20 points in order for them to function.
For additional information on barcode font types, including licensing parameters, please see https://www.idautomation.com
| Barcode Font Type | Font Point Size Required to Match DPI of Printer When Printing Less Than 600 DPI - 203 DPI Printer | Font Point Size Required to Match DPI of Printer When Printing Less Than 600 DPI - 300 DPI Printer |
|---|---|---|
| Code 39 (Version 5.1 or greater) | 6, 12, 18, 24, 30, 36, and other multiples of 6 | 4, 8, 12, 16, 20, 24, 28, and other multiples of 4 |
| Code 128 (Version 5.1 or greater) | 6, 12, 18, 24, 30, 36, and other multiples of 6 | 4, 8, 12, 16, 20, 24, 28, and other multiples of 4 |
| Codabar1 | 5, 10, 15, 20 | 3.8, 8, 16 |
| Interleaved 2 of 51 | 12.5, 25 | 5.75, 10, 14 |
| MSI1 | 6, 11.5 | 2.5, 5, 7.4, 10, 9.8, 12.2 |
| UPC/EAN | 17, 22, 30 | 15, 20, 25 |
| Universal Barcode Font | 6, 12, 18, 24, 30, 36, and other multiples of 6 | 4, 8, 12, 16, 20, 24, 28, and other multiples of 4 |
Footnotes
In testing, Codabar, Interleaved 2 of 5, and MSI were very close to printing properly at the font sizes listed in this chart. However, to create completely accurate ANSI grade A barcodes on low resolution printers, IDAutomation recommends the Universal Barcode Font Advantage software package. This product creates accurate barcodes on low resolution printers when printing at narrow to wide ratios of 2:1 or 3:1. The Universal Barcode Font Advantage software also works on any operating system, code page, and locale, and creates Codabar, Interleaved 2 of 5, and MSI, as well as other barcodes such as Code 128 and Barcode 3 of 9 as a single font. ↩ ↩2 ↩3