Barcode Printer DPI: What You Need to Know

Barcode Printer dpi: What You Need to Know

by Karl Trepagnier | Senior Solutions Architect

open barcode printerIf you’re considering buying a barcode label printer, you’ve probably discovered that there are a wide variety of options to choose from depending on the needs of your application. One of the many factors you should evaluate is printer resolution, typically referred to as dpi, or dots per inch. Barcode printers are available in low-to-high dpi configurations, typically 203, 300, 406 or 600dpi. But how do you know which resolution will work for you? And what other elements should you consider? Let’s explore what you need to know about printer dpi before buying a barcode label printer.

It’s important to have a clear understanding of your dpi requirements before purchasing a barcode printer so that you don’t make a bad investment. Printer dpi is not a setting that can be adjusted or changed after you’ve purchased the equipment.

What is printer dpi?

Printer dpi determines the resolution of your barcode labels. Higher resolution printers create sharper images than lower resolution printers. For example, a 600dpi printer will produce very clear, defined barcodes with literally 600 dots per inch, which is considered very high resolution. On the lower end of the spectrum, a 203dpi printer will create barcodes with fewer dots per inch, and this works well for larger label sizes such as standard shipping labels that are still scannable at a lower resolution. Generally speaking, the smaller the barcode, the higher resolution you need in order to make sure it’s scannable. 

Why is printer dpi important?

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Printer dpi has a big impact on barcode quality and readability. If your barcode resolution is too low, the lines or squares may appear grainy or irregular, and a barcode scanner may not be able to read them. If you are a distributor to large retail outlets, the consequences of unscannable barcodes can have a serious impact on your bottom line in the form of chargebacks, late deliveries and fines. (Read more about The Risks of Using the Wrong Barcode Supplies)

It’s important to have a clear understanding of your dpi requirements before purchasing a barcode printer so that you don’t make a bad investment. Printer dpi is not a setting that can be adjusted or changed after you’ve purchased the equipment. Each printhead has a minimum and maximum range of label sizes and resolutions that it can print. As a core component of a barcode printer, the printhead isn’t something that can be swapped out easily if you need to print outside its range. 

Impact on barcode quality

Even though printer dpi can negatively affect your barcode quality, it’s often overlooked as the culprit. As an example, one of our Peak-Ryzex Direct customers recently had a problem with poor barcode print quality. The customer initially thought there was something wrong with their printer, but according to the OEM information, the printer, media, and ribbon were all working properly. After extensive analysis and testing, our technicians determined that the problem was caused by the label design being out of sync with the printer resolution. Let’s take a look at what this means and how you can avoid it.

After extensive analysis and testing, our technicians determined that the problem was caused by the label design being out of sync with the printer resolution.

Label design considerations

Achieving high barcode quality involves a combination of the right labels, ribbon, a well-maintained printhead, and other factors, but it also requires your label design to be in sync with your printer dpi. Each bar and space in your barcode have to print with the correct dimensions, and if your printer specs aren’t right, your label quality will suffer.

When designing your labels, you have to consider the dpi at which they will print -- different printer resolutions require different label designs. This means if you need to print a label on your 300dpi printer, you need to design the labels to print at that dpi. You can’t send the same label to a 203 dpi and 300dpi printer and expect both to print properly. The label must be designed to match the resolution of the printer.

Label design software allows you to make adjustments to your label before you print, which can minimize the number of labels used for test printing. Printer dpi is one of the main reasons that you shouldn’t use barcode fonts – they can’t be adjusted to match the dpi of your printer.

In most cases, label design software is included when you purchase a printer. For example, Godex offers an intuitive, feature-rich software with their printers. You can also purchase separate products, such as BarTender software which is available in Basic, Pro, and Automation versions depending on the complexity of your operations.

Determining the printer resolution you need

To figure out the printer resolution that’s right for you, there are two questions you should ask yourself before moving forward.  

1. Does my industry or application have label requirements?

Depending on the type of product you’re labelling, it may have compliance requirements. In many cases, there are specific elements that must be included on your label.

Here are a few examples:

2. What size barcode do I need to print?

Barcode resolution is determined by the size of the barcodes you need to print. The label size may be specified in the compliance requirements, but if not, you will need to determine the size based on the elements in your barcode.

Barcode sizes are commonly measured in mils, which are also referred to as the x-dimension. They represent the width of the narrowest bar in thousandths of an inch. A standard 10 mil barcode means the narrowest bar measures 0.10 inches. If you need to print a 10 mil barcode, you will need to use a 600 dpi printer to make sure the resolution is high enough. See the table below for a helpful reference.

Printer 203 dpi 300 dpi 406 dpi 600 dpi
Dots -1 0.00493 0.00333 0.00246 0.00167
2 0.00985 0.00667 0.00493 0.00333
3 0.01478 0.01000 0.00739 0.00500
4 0.01970 0.01333 0.00985 0.00667
5 0.02463 0.01667 0.01232 0.00833

Mils is also used to determine the minimum distance at which a barcode scanner will be able to read the label. If your scanner reads a minimum bar width of 10 mils, it will not be able to read a 5 mil barcode. Label design software allows you to set the mils or x-dimension so that the barcode will print with the correct specifications.

Barcode mils and dpi

You can use dpi to calculate barcode mils. For example, if your printer is 300dpi, that means literally one inch divided by 300 dots per inch, which equals 0.00333. This means one dot equals 0.00333 inches, and 1 mil equals 0.001 inch. So 0.00333 divided by 0.001 equals 3.33 mils. If you need a 10 mil barcode, then ten divided by 3.33 equals three dots.

Mils Millimeters Inches
1 0.0254 0.001
2 0.0508 0.002
3 0.0762 0.003
4 0.1016 0.004
5 0.1270 0.005
10 0.2540 0.010
15 0.3810 0.015
20 0.5080 0.020
25 0.6350 0.025
30 0.7620 0.030
35 0.8890 0.035
40 1,0160 0.040
45 1,1430 0.045
50 1.2700 0.050

Smaller labels require higher dpi printers; as the barcode size decreases, dpi typically needs to increase to ensure readability.

If you are using barcodes for your own internal tracking, then printer resolution and label design may not be a high priority for your company. But if your goal is to grow your business and distribute your products to as many stores as possible, you need the ability to print high quality barcodes that meet the specification of different suppliers and retailers. This requires a clear understanding of your barcode label requirements and the right printer dpi and label design software to create the perfect barcode.

Karl Trepagnier
Senior Solutions Architect, Peak-Ryzex
As a dedicated solutions architect for Peak-Ryzex Direct customers, Karl brings extensive technical expertise with multiple data collection technologies, including WLAN, RFID, mobile computing, printing, media and software. Prior to joining Peak-Ryzex, Karl spent eight years in the RFID industry where he focused on the healthcare and pharmaceuticals markets. Before that, Karl spent 26 years at Intermec as a Sr. Field Engineer.


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