This document describes the main specifics of bar code recognition and how to resolve the most frequently encountered issues when working with bar codes.
Choose an Appropriate Bar Code Type
Selecting an appropriate bar code type (symbology) depends on your specific business requirements and the applied industrial standards.
In general, consider using Bar Code 2 of 5 Interleaved for encoding digits and Bar Code 39 for encoding the full range of ASCII characters.
Insert the Function Code One Character (FNC1) or the Application Identifier into a Bar Code
Some encodings enable you to insert a special FNC1 character for separating application identifiers from the rest of the bar code.
According to the GS1 specification, the FNC1 character is always inserted at the first position of the encoded data. Other identifiers can be inserted manually using the default “#” character.
Although you can use any ASCII character as the FNC1 placeholder, it will not be a part of the encoded data as it does not have any direct ASCII representation.
For the list of the available application identifiers, refer to the official documentation at www.gs1.org.
Specify the Bar Code Resolution on Export to Third-Party Formats
At present, only export to PDF preserves the original bar code in its vector form. Export to other formats will keep only the rasterized version of a bar code (with the default DPI set to 96).
For XLSX and XLS export, the output resolution can be set up manually using the Rasterization Resolution property.
This document section provides solutions to the most common issues that you may encounter when creating bar codes.
- The bar code is too “dense”
The more information you wish to encode, the more bars should be drawn and the larger the bar code should become.
The bar code’s Module property specifies the width of the narrowest bar in a bar code. Although you can set this property to a very small value, the actual value is determined by the maximum resolution of your bar code printer device. Alternatively, consider using the Auto Module option to automatically calculate the optimal bar size based on the current bar code dimensions.
For example, when the Module is set to 0.015 inches and the printer resolution is 300 DPI, their product equals 4.5, which may be rounded to 4 or 5 pixels for different bars and result in bar code recognition errors. In this case, the Module property should be set to 0.01333 (to make the bar width equal to 4 pixels) or to 0.01667 (to make the bar width equal to 5 pixels).
- The bar code is correctly displayed on the preview but it is not scanned
Make sure that your scanner has been correctly set up to be able to recognize a specific kind of a bar code. If you are not certain about how to operate the scanner properly, please refer to its
Avoid scanning bar codes from the monitor screen (e.g., using an application installed on your smartphone), because the screen DPI may not be sufficient to effectively recognize each particular bar.
- The bar code is correctly displayed on the preview but it is scanned incorrectly
The cause for this problem may be an encoding issue specific to the “binary” input mode.
By default, the UTF-16 encoding is used. However, your scanner device may use a different encoding model or even a codepage (i.e., a specific table that maps abstract values to real human-understandable characters). For additional information on this subject, please refer to the specification of your scanner device.
- The “There are invalid characters in the text” error occurs
Different bar code symbologies define different ranges of allowed characters under different character sets. To avoid this error, please check the bar code specification.