Laser Engraving a Photograph

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Laser Engraving a Photograph

Using a laser to engrave a photograph onto wood, acrylic, or other material can create a stunning effect. Makers attempting this type of project can be frustrated trying to understand why one photo creates a beautiful engraving but another photo creates engraving that is dark and muddy looking or light and lacking in details. This page will describe some of the attributes that make a photograph suitable for engraving and will outline in general terms the steps to take to make a photo reproduce better as a laser engraving. Links will be provided to external tutorials on how to adjust your photos to get the best possible results.

The Problem

The ideal photograph is a continuous tone image, this means that any point in the photo is made up of a particular tone (a shade of grey or color) that could be completely different from any other point in the photo. There could be a nearly infinite range of tones in a photograph. Traditional darkroom photography processes used with silver-based negatives and print paper approached this ideal and were able to reproduce such a wide range of tones that there appeared to be no discrete or separate steps between tones. These prints were considered continuous tone (or contone) images.

When 19th century printers tried to incorporate the new art of photography into their work they ran into a similar problem that makers face when trying to engrave a photo. Printing, like laser engraving, is a digital process (even though no one knew to call it digital at the time). A printing press can either apply ink or not apply it. Initially printers were only able to include an image by having an artist create a wood cut or metal engraving of that image.

A technical solution to this problem was created by the halftone process.

Halftones and Related Topics

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General Tips for Converting a Photo to a Laser Engraving

• Start with a Quality Photo
  • Criteria 1
  • 2
  • 3
• Crop the photo
• Remove the Background or Eliminate Unnecessary Elements in the Background
• Convert Image to Greyscale
  • Greyscale Options
• Edit Photo
  • Enhance highlights in any large dark areas of photos such as a person's hair.
  • Adjust the darkest point on the face to be 10-15% black.
  • The lightest highlights should be almost without black color, about 3% TO 6% is a good rule of thumb. A highlight with 0% black looks bad.
  • Exaggerate the variation in hair color, make light strands lighter using the Dodge Tool (O) Range: Highlights.
  • Make dark hair strands darker using the Burn Tool (O) Range: Shadows.
• Adjust Image Size, ensuring resolution is Resolution: 200 pixels/cm (508 pixels/inch)
• SHARPEN (Filter > Sharpen > Unsharp Mask)
• Convert Image to Bitmap (Image > Mode > Bitmap | Output: 200 pixels/cm (508 pixels/inch)| Method: Halftone Screen Frequency: 200 lines/cm (508 lines/inch)| Angle: 15 degrees| Shape: Round | Save As Format: BMP File| Format: Windows | Depth: 1 Bit)
• TEST USING SMALL PORTION OF IMAGE SUCH AS EYE

How-To Guides to Optimizing a Photo for Laser Engraving

• https://support.glowforge.com/hc/en-us/articles/360033633534-Prep-a-Photo-Engrave-in-Photoshop

• https://www.instructables.com/How-to-Laser-Engraving-Photo/