There are times when a black label with white lettering is required from a thermal printer. This situation, however, can create some confusion since most industrial grade labeling software is made for the traditional white label with black lettering. Users can find this situation even more complex when barcodes are involved. Therefore, careful consideration must be given to the approach used to create these unique labels.
Reverse or Inverted Barcode
Before delving into the three different approaches, it is VERY important to understand the concept of reverse or inverted barcode. Simply put, the barcode you see printed on black labels are not the same as the barcode printed on white labels. Critical differences include:
- The stripes are reversed - the black lines are changed to white spaces and the white spaces become black lines. The width of the converted lines and spaces (in multiples of the x-dimension or smallest common element width) must stay exactly same as the original after conversion. In other words, the width of a new large space must be the exact width of the large line it replaced.
- The quiet zone MUST be black - the quite zone around the barcode (i.e. free space immediately surrounding the barcode) must now be black instead of white. Just as a barcode scanner requires sufficient white space around the traditional barcode to make it readable, a scanner reading a reverse or inverted barcode will require the same amount of black around the barcode.
- Font used for human readables must support inverted characters - most printers do not have printer resident fonts with inverted characters. Thus the label designer must take that into consideration and make sure the human readable font is a graphic / windows based font that provides a set of inverted characters.
- Not all scanners can read inverted barcode - this is a different form of the barcode. Although a vast majority of modern day scanners are programmed to read reverse or inverted barcode, please be aware that some older models may not have this capability. Further, beware that even scanners that can read inverse code may have this feature turned off.
The Three Approaches
The approach used to create these labels will dictate how you should configure the software and printer. We recommend picking one approach and staying consistent with it across all similar labels. The rules of label design will change depending on your approach, so consistency will help reduce labeling errors. More technical information about how to make these three approaches work and related technical articles for specific software configurations and settings can be found in the Efficient Business Integrators On-Line Knowledge Base.
EBI Online Knowledge Base Article: Printing Labels in Reverse, Negative, or White on Black – Reference Article
Approach #1 - Use Black Label Stock
This is the most intuitive, but probably least efficient of the three approaches. If you want to print white on black, doesn't it make sense to have black label stock and white ribbon? This approach can work. The label designer needs to take these factors into consideration:
Thinking 'In Reverse'
Industrial label design software is made with the assumption of black on white (black ribbon and white labels). Therefore, label design users need to think 'in reverse' when creating the label. What looks black on the screen will be white on the label and vice versa. Graphics and barcode need to be reversed individually.
Remember to Reverse All Barcodes
Your label software will render the barcode with the assumption that the label is white. It has no way of knowing on what material you are printing. Therefore, it is up to the label design user to remember to invert the barcode stripes and spaces for EVERY barcode on the label. Most industrial label design software have this capability, but it is up to the label designer to remember.
Separate Label Stock and Ribbon Required
You will need to order and stock separate label stock and ribbon for these print runs. Also, the print user will need to remember to check the label stock and ribbon before running the print job. Again, the label software does not know what label material you are using. When there is a change over, remember to add some system downtime to give the print user time to swap out the label stock and ribbon.
Approach #2 - Design the Label 'in Reverse' (White Label Stock)
This avoids the need of ordering and maintaining black label stock. The label is designed with the colors reversed from the ground up. The background of the label needs to be changed to black. The font color of the text is white. The label looks on the screen as it will print.
Limited Thinking 'in Reverse'
Since the label design is made to look like the final label, there are only two areas that require the design user to think 'in reverse':
- Graphics - need to be reversed using photo editing software. Once reversed, the image can be imported into the label design and saved.
- Barcodes - each one needs to be reversed, similar to Approach #1, using features within the labeling software. Related issues such as providing a black quiet zone around the barcode and using fonts that contain inverted images for the human readable still must be considered.
Easier to manage than Approach #1, but this approach still requires some complex thinking and technical understanding of barcode and how it works.
Approach #3 - Use Printer Drivers (White Label Stock)
The easiest and least expensive approach is to design your software normally and use the printer driver to reverse the colors. Printer drivers provided by the printer manufacturer (aka Windows print drivers) and sometimes by the label software manufacturer often have this feature. If available we highly recommend this approach. Benefits include:
- No need for special label stock or ribbons - this will help keep printing costs down, reduce printer downtime, and reduce errors related to using the wrong stock and/or ribbon.
- Easy to maintain, no thinking 'in reverse' required - reducing complexity in the label design means fewer label design errors and less testing / fixing of label designs.
- Inverted barcodes automatically created - no need for the label design user to understand and respect the rules of inverted barcode (i.e. maintaining line and space widths, using a black quiet zone, and checking human readable fonts)
Although Approach #3 is generally preferred; all three approaches will work. The most critical aspect in label design is to remain consistent with a single approach. As you could probably see in the detail above, different approaches require different settings and configurations. Understanding the approach, staying consistent, and working with your labeling system integrator will help keep your white on black label printing reliable and easy to use.
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EBI Online Knowledge Base Article: Printing Labels in Reverse, Negative, or White on Black