What is Barcode Resolution and Does DPI Matter?

What is Barcode Resolution and Does DPI Matter?

Barcode Basics | 16 June 2020

Posted by John Masica

What is Barcode Resolution and Does DPI Matter?

As a barcode supplier, we are often asked about DPI—what is it? Does it matter? On the other hand we find that there are some common misconceptions and assumptions regarding DPI we often have to explain.

So here we aim to explain what DPI is and the role it plays when it comes to barcodes specifically so you can more confidently invest in the best print strategy for your application. Let’s get to it!

What is barcode resolution/DPI?

When talking about barcode resolution, we’re talking about the same thing as print image resolution. Print image quality, or resolution, is measured in DPI or “dots per inch”—a literal description of the ink dots spread across the media depicting the final image.

While the dots may not be visible to the naked eye in most cases—they are there! In fact, they’re there before the image is even printed in a form you’re probably also familiar with—pixels. Pixels on a computer are very different from dots on a page, however they serve the same core purpose—spots that when viewed from a distance merge together to form a comprehensive image.

In a few words, barcode resolution is the overall quality of your barcode image measured in pixels per inch (PPI) on screen, and in DPI when printed onto your media—but what does that mean to you?

 

Does Barcode DPI Matter?

To a certain degree, the higher the dpi, the sharper the image and the lower the dpi the more likely it is to have a grainy appearance. This is because a higher resolution contains a higher density of dots. If you’ve ever grabbed an image from the internet and printed it only to find it didn’t look quite as you expected, you’ve already witnessed this first hand.

So yes, DPI does matter, and while the evidence so far points to high DPI being better—don’t rush out to buy the highest DPI printer you can find! A couple factors need to be taken into account when determining the best DPI range for your barcodes:

 

Barcodes are not Photographs

First of all, while barcodes are images often stored digitally as image files similar to photographs or graphics on your computer—jpg, png, img…etc.—they are very different from photos or digital drawings.

One of the biggest ways barcodes differ from a photograph or visually pleasing graphic is their purpose. Barcodes are a graphic representation of computer readable information—essentially a computer readable language.

This is a critical point to remember—barcodes are not intended to be interpreted by the human eye. This means that as long as your scanner can pick up the code and your computer can read it the barcode has served its purpose. Similar to handwriting—as long as it’s legible you understand the message.

barcodes

Barcodes are also relatively simple in their structure—containing lines or blocks of black ink against a white background—in contrast to photos. Photographs require a range of gradation—and typically color to accurately depict a subject. In order to create the necessary gradients and colors a high concentration of dots are required—and an even higher concentration is required to ensure a crisp image that is not only decipherable by human eyes, but appealing.

In short, barcodes generally don’t warrant the highest of DPI under the context of their purpose and complexity unlike printed graphics or photographs. However, that doesn’t mean barcodes never require high resolution—size plays a big role in your DPI needs.

 

Size Matters

For the most part you’ll find barcode printers with DPI capabilities of 200, 300 and 600 (though there are some 400 DPI printers around)—each of these will be best suited for different density needs.

200 DPI is best suited for less dense codes. Even with lower DPI the image can remain crisp and readable to the scanner. Medium to high density barcodes will perform much better at 300 dpi, and codes requiring especially high density will require at least 600 dpi.

Typically, lower density is best suited for larger barcodes and higher density is most suitable for smaller barcodes—especially smaller 2D barcodes—where sharp edges are critical in preventing misreads. But depending on what code you’re using, your needs may differ.

Also, keep in mind that you can print low density codes with a high density printer so you won’t need a different printer to meet all of your size and density needs. Utilizing a high DPI printer for low density printing can decrease the likelihood of misreads or no-reads by increasing the quality of those codes—where there was one dot with a 200 DPI printer, you now have 3 dots with a 600 DPI printer.

 

When to Invest in High DPI?

As we made clear in the last section, DPI does matter—but high DPI isn’t always the answer. There are three main circumstances where you might benefit from investing in a high resolution printer:

 

1.    You are required to by an outside party

Some industries—such as certain areas of the healthcare industry—may have standards in place specifying a minimum barcode DPI for use on important samples or documents.

There is a lot at stake when a sample is taken for testing—time and effort cannot be wasted when a patient is expecting a potentially life changing diagnosis. So, standards may be put in place to prevent potential liability issues or delays.

It’s also important to note that very small barcodes aren’t uncommon in healthcare—so these standards align with common practices.

 

2.    Your barcodes are extremely small

We’ve already touched on this, but particularly small barcodes—especially very small 2D barcodes—often perform best when printed at high resolution.

All barcodes perform best with sharp edges, but a sharp edge on a very small barcode isn’t achievable without high DPI. With the smallest of barcodes too much space between dots can lead to misreads or no-reads.

3.    Your needs vary—or might in the future

Maybe you deal with multiple sizes of barcodes, or plan to accommodate smaller barcodes in the future. In this case, you’ll want to invest in a higher DPI model to ensure you can accommodate all of the size and density requirements you plan to utilize.

If you’re unsure and have the budget it may not be a terrible idea to go up a level to ensure your investment is sound even if future changes impact your barcodes. Typically, there won’t be an enormous difference in cost so in many cases it’s manageable to upgrade from 200 DPI to 300 DPI or 300 DPI to 600 DPI. You can expect to spend up to a few hundred dollars more if you choose to upgrade to the next resolution level.

 

Our main goal here, is to help our customers who may not be barcode experts better understand the role of barcode resolution and DPI so they—or you, can get the most value out of your printer purchase.

While it may not be far from the truth to say the higher the DPI the better—if 300 dpi works for your application, why spend more on a high-resolution printer you don’t gain value from? Or, on the other end of the spectrum, you end up losing money when you try to save by purchasing a printer that isn’t able to provide the resolution you really need.

As always, this is one reason we recommend working with a single supplier for your barcoding needs. With one supplier who is familiar with your needs and practices providing you with all the equipment you need to complete your barcode strategy, they can lead you in the right direction when it comes to the small but critical details like DPI.

 

Experiencing Scan Issues? Check out this blog post to find simple solutions to common scan problems

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John Masica

Based in St. Paul, MN, USA, John Masica is Computype’s Technical Support Specialist. Specializing in label printer maintenance and engineering, John is the go-to person for all things label printing. Through his 24 years here at Computype, he has learned many tips and tricks to make your label printing easier and more efficient.