Image Resolution and How it Affects Engraving

1200 DPI resolution is used for projects that need the best engraving quality. It is ideal for very small fonts or when deep engraving is important.

How do you know which DPI setting is right for your project?

Print quality is often determined by the resolution of an image, and is one of the main variables to consider when laser engraving. Resolution is expressed in DPI or dots per inch and is determined by the number of lines or dots that are engraved for every inch of movement. Each horizontal line of dots the laser produces is referred to as a raster line. A higher resolution selected in the print driver will make the dots engrave closer together, and will produce a higher quality result.

Although resolution does play a big part in engraving quality, keep in mind that engraving resolution is only one factor in determining image quality. The focus, brightness, and contrast elements of an image can have greater influence on the look of the final engraving than resolution alone. If low-quality artwork is used, even the highest resolution setting in the print driver will not improve the engraving. Also, keep in mind that image quality is subjective. Engraving a project at 300 DPI may be just fine for some images and customers, while 600 DPI is required as the absolute minimum for others.

These 3 examples exhibit qualities that will not produce the best engraving results.

The first example is a photograph taken at an event where the overall light is too bright and includes a very hazy look.

The second example is a low resolution logo provided as a 72 DPI image, rather than as vector artwork or in a vector format. 72 DPI is too low a resolution for a logo engraving project. It’s best to receive logo artwork as a vector image when possible.

And the third example is of a photograph that is very dark and includes very little contrast. These three photos illustrate some of the image issues that cannot be fixed with resolution settings alone at the laser.

Now we’ll discuss a bit more about how DPI works at the laser. This diagram shows the concept of raster lines and dots-per-inch (DPI), and the difference in dot density between 75, 300, and 600 DPI. Each dot represent a laser pulse, and the arrows represent the change in direction of the optics assembly for each raster line. Note how sparse the dots are at 75 DPI, and how the dots are very close and overlapping at 600 DPI.

How Resolution Affects a Job’s Completion Time

Generally, the time it takes to complete an engraving job is significantly affected by resolution. The higher the resolution, the more time it will take to complete an engraving job. While a higher resolution setting does increase the time it takes to complete an engraving, it allows you to achieve greater depth in materials like wood and rubber without having to reduce the speed of the laser. High resolution is also ideal for highly detailed wood engraving, such as the Epilog Aztec Calendar, and rubber stamps, which typically include small typefaces, intricate details, and more depth in the recessed areas.

There will be times when your customer requests a large number of pieces, and it will be important to minimize the time spent completing the job, without sacrificing quality. Optimizing a projects DPI by selecting a lower resolution will help reduce engraving time and increase profits.

These tiger photo engravings on anodized aluminum show the quality difference at 300, 400, and 600 DPI. Out of these examples, you can see the 600 DPI engraving produced a high-quality engraving and took 2 min and 44 secs to complete. But, the 400 DPI result is nearly just as good, and only took 1:49 seconds to complete.

As an example, if a customer ordered 100 of these tiger cards, then completing the 100 cards at 600 DPI would take around 4 hrs and 35 minutes to be completed, but engraving the project at 400 DPI would allow you to complete the project in just over 3 hours.

Combining DPI and Dithering Pattern for More Time Savings

There are other techniques to save you time without sacrificing engraving quality. Your Epilog Laser machine includes dithering pattern options, which eliminate the perceivable dot pattern you see when engraving at lower resolutions with the Standard dithering option.

In this example, note the dot pattern in the engraving on the left and the absence of the perceivable dot pattern in the example on the right. Each of these engravings were produced using 300 DPI, and the time to complete them was the same, but the one on the left was engraved using the Standard dithering pattern, while the engraving of the right was completed with the Stucki Dithering pattern.

Utilizing Epilog’s Stucki Dithering setting and engraving at 300 DPI produces a high-quality result similar to the 600 DPI, and also provides a large time saving advantage.

Applying this combination of settings to the previous project example of engraving 100 tiger cards, the engraving project would take only 2 hours and 17 minutes to complete, further increasing the time savings and profitability of this project.

As a final example and to further illustrate how DPI effects engraving, we’ve used a 50-watt Helix to engrave a grayscale clip art image, with settings of 45 percent speed and 100 percent power. The only thing that changed between each engraving is the resolution.

When it comes to settings and the final results of a project it can come down to a matter of personal preference as to which resolution looks better, but these photos show the dramatic difference resolution can make, especially when engraving grayscale images.

Matching Resolution Settings to Your Material

We recommend consulting your manual or the included material settings installed with your machine driver and the Epilog Job Manager.

75-200 DPI

Resolution settings in this range are typically used for non-production purposes where you want to experiment with image engraving location, or if you want to quickly produce a rough draft engraving. A low resolution can also be useful when engraving products that don’t require much material to be removed during engraving, such as fabric.

300 DPI

300 DPI is a versatile sweet spot for laser engraving. This setting is useful when engraving materials such as wood, glass, marble, plastic and other items that don’t benefit from the engraved dots being close together.

400 DPI

This resolution value is ideal for many applications. It combines very good image quality with fast engraving times. Many users like 400 DPI for all of their work.

600 DPI

600 DPI provides fine detail, depth, or is useful when high-end results are required.

1200 DPI

1200 DPI resolution is used for projects that require the best engraving quality possible, when engraving extremely small fonts, or when depth of engraving is the goal use this resolution.

Things to Remember

• When it comes to settings and the look of the final result, personal preference is something to consider, but also try to minimize the time it takes to complete a project when possible.
• When experimenting with new products and materials, make sure to have extras on hand for dialing in the best settings and results.
• Be sure to consult your manual as a starting point for materials settings, and also utilize the epiloglaser.com website as a resource for additional product ideas and materials settings. We provide Sample Club articles monthly.