Laser engraving requires careful image selection and preparation to ensure precise and professional results. This guide outlines the steps for preparing your image, explains raster and vector file differences, and includes helpful keyboard shortcuts for software like Adobe Photoshop, GIMP, Adobe Illustrator, and Inkscape.
1. Understanding Image Types
Raster Images
- Definition: Raster images are based on pixels (dots), arranged in a grid where each dot has a specific color or shade.
- Common File Types: JPEG, PNG, BMP, TIFF, GIF.
- Software for Editing: Adobe Photoshop (commercial) or GIMP (freeware).
- Usage in Laser Engraving: Best for photos and complex designs with gradients or textures.
- Important Considerations:
- Higher resolutions (300 dots per inch (DPI) or higher) ensure clarity and avoid pixelation. Low-resolution images (<120 DPI) are unsuited to engraving.
- Convert the image to grayscale to ensure compatibility with laser engraver (which can reproduce only white, black, and shades of grey).
- All raster images contain a fixed number of dots. Enlarging the image spreads those dots over a larger area, reducing the overall image resolution. Shrinking the image compresses those dots into a smaller area, increasing overall image resolution.
- Check your image resolution in Photoshop by going to Image > Image Size or pressing Ctrl+Alt+I (Windows) / Cmd+Option+I (Mac)., or in GIMP by navigating to Image > Print Size.
Vector Images
- Definition: Vector images use math to describe (lines, shapes, and fills) that are infinitely scalable without losing quality.
- Common File Types: SVG, AI, EPS, PDF, DXF.
- Software for Editing: Adobe Illustrator (commercial) or Inkscape (freeware).
- Usage in Laser Engraving: Ideal for cutting and sharp-edged designs, logos, and text.
- Important Considerations:
- Convert all text to outlines (paths) to prevent font substitution.
- Use hairline stroke widths for cutting paths.
2. To Prepare Your Image for Engraving
For Raster Images
- Clean the Image:
- Remove backgrounds and unnecessary details using Photoshop's Eraser Tool (E) or GIMP's Paths Tool (B).
- Convert to Grayscale:
- Photoshop: Use Ctrl+Shift+U (Windows) / Cmd+Shift+U (Mac) or go to Image > Adjustments > Black & White.
- GIMP: Navigate to Image > Mode > Grayscale.
- Adjust Brightness and Contrast:
- Photoshop: Use Ctrl+M (Windows) / Cmd+M (Mac) for Curves or Ctrl+L / Cmd+L for Levels.
- GIMP: Open the Brightness-Contrast dialog with Shift+C.
- Resize the Image:
- Photoshop: Use Ctrl+Alt+I (Windows) / Cmd+Option+I (Mac) to adjust resolution and dimensions.
- GIMP: Use Ctrl+Shift+R to scale the image.
For Vector Images
- Simplify the Design:
- Use Illustrator's Direct Selection Tool (A) or Inkscape's Node Tool (N) to edit paths.
- Set Line Properties:
- Illustrator: Open Stroke Panel (Ctrl+F10) and set stroke width to hairline (0.001 inches).
- Inkscape: Adjust stroke width in Fill and Stroke Panel (Shift+Ctrl+F).
- Convert Text to Outlines/Paths:
- Illustrator: Use Ctrl+Shift+O (Windows) / Cmd+Shift+O (Mac).
- Inkscape: Use Ctrl+Shift+C.
- Resize and Scale:
- Illustrator: Use Shift+Drag to maintain proportions.
- Inkscape: Use Ctrl+Drag.
3. File Compatibility
Preferred file formats are:
- Raster Engraving: JPG/JPEG or TIFF (grayscale).
- Vector Engraving/Cutting: SVG or EPS.
Once your file is prepared, bring it to the Makerspace. The easiest way is to use a flash drive, but any cloud storage is also available. Makerspace staff can help you from here.
Tips for Success
- Use High-Quality Images: Low-quality images will produce subpar results.
- Save an Editable Master File: Retain an original file in Photoshop, GIMP, Illustrator, or Inkscape for future tweaks.
- Learn Shortcuts: Familiarize yourself with the above keyboard commands to streamline your workflow.