November '20

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6 6 L A S E R E N G R A V I N G R E P O R T 2 0 2 0 G R A P H I C S - P R O. C O M most engraving materials like wood or acrylic, you are creating a dark mark wherever the laser hits the material. On material like black marble or slate, you are doing the opposite—you are creating a white mark wherever the laser fires, not dark. Inverting just changes all the black dots to white and vice-versa. In addition, there are a few things you can experiment with: • Shading: Earlier we mentioned converting your image to grayscale prior to engraving. It's important to keep in mind that the darker an object is in a photo, the deeper it will engrave. So, even after converting your photo to grayscale, you may need to further manipulate your image to lighten up any especially dark areas. • Power: Engravers are often accustomed to using higher power settings to laser through powder coating or to create a deeper, darker mark on a plaque. Photos, however, don't require all that power. Of course, you want an engraving with contrast, but in this application, you're not going for a deep engraving. Because the dots in your photo will overlap, using too much power when engraving photos can make them appear flat and less detailed. DITHERING PATTERNS Dithering defines how the dot patterns will be engraved in images that contain grayscales. Epilog's dashboard features a variety of photo engraving dithering patterns for users to experiment with: • Floyd-Steinberg: Produces an almost wave-like pattern to an image. This works well for some photos containing a great deal of detail. Photos with more monotone swatches of color may not be as pleasing as Jarvis or Stucki modes. • Jarvis: Many users find this mode good for engraving photographs at 300 DPI. This mode produces a nice-looking pattern on almost all photos. • Stucki: This mode produces results that are only marginally different than the Jarvis dithering pattern. It is also particularly good for engraving photographs at 300 DPI. The differences between Jarvis and Stucki are subtle. • Bayer: This mode is an efficient and widely used halftoning technique. It is distinguished by its noticeable crosshatch patterns. Bayer (ordered) dithering is more suitable for line-art graphics. Note that the dithering patterns are labeled differently among the various machines. Consult your user's manual for those specific to your brand as well as what each works best for. PRACTICE MAKES PERFECT If you're a photo engraving newbie, the first thing you should do is set aside some time to familiarize yourself with the process. Start with what you think would be a good photo for engraving and test out the tips we've discussed. Use scrap materials or check out your local thrift store for some inexpensive items you can test on. As with any technique, the more you experiment, the sooner you'll begin to understand the nuances of different types of photos, laser parameters, and material. Before you know it, you'll be able to easily discern what makes a good photo engraving candidate and how to process it perfectly for optimum results. LER AMY DALLMAN is the marketing communications specialist for Epilog Laser. She's responsible for much of the company's internal/external communications, such as eNewsletters and press releases. She also heads up Epilog's public relations and social media efforts. She's been with Epilog since 2007. Dithering defines how the dot patterns will be engraved in images that contain grayscales. Top to bottom on an Epilog machine: Floyd-Stein- berg, Jarvis, Stucki, and Bayer. Note that these labels vary among the different manufacturers. IF YOU'RE A PHOTO ENGRAVING NEWBIE, THE FIRST THING YOU SHOULD DO IS SET ASIDE SOME TIME TO FAMILIARIZE YOURSELF WITH THE PROCESS. L A S E R E N G R A V I N G R E P O R T 2 0 2 0

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