Best Image Format for Laser and CNC Engraving
SVG is the best format for laser and CNC engraving because engraving machines follow vector paths to cut and etch materials with maximum precision. Vector artwork translates directly to machine toolpaths, producing the sharpest possible results on wood, metal, acrylic, glass, leather, and other engraveable materials.
For raster engraving (where the laser scans back and forth like an inkjet printer to create grayscale images), PNG or BMP at high contrast produces the best results. The key is providing the engraving software with clean, high-contrast artwork that the laser controller can accurately interpret.
Here is how to prepare artwork for both vector and raster engraving workflows.
SVG for Vector Engraving and Cutting
Vector engraving follows the exact paths defined in your SVG file. The laser or CNC bit traces along each path at the specified speed and power, creating precise lines, curves, and shapes. This is the highest-quality engraving method for text, logos, line art, and geometric designs.
SVG is preferred over other vector formats (AI, DXF, CDR) because it is an open standard supported by virtually all laser engraving software (LightBurn, LaserGRBL, RDWorks, Glowforge interface, and others). Most engravers can open SVG files directly.
- Convert all text to paths/outlines. The engraver may not have your fonts.
- Remove all fills for cut-only paths. Use strokes at the hairline width.
- Set stroke colors to match your software's layer conventions (often red for cut, blue for engrave).
- Remove hidden layers, clipping masks, and unnecessary metadata.
- Ensure all paths are closed (joined start and end points) for cutting operations.
- Set the document size to match your material/workpiece dimensions.
PNG and BMP for Raster Engraving
Raster engraving uses the laser in a scanning mode to etch images onto materials. The laser power varies pixel by pixel to create light and dark areas, producing a grayscale image on the surface. Photographs, complex illustrations, and halftone patterns use raster engraving.
PNG is the best format for raster engraving artwork because it preserves exact pixel values without compression artifacts. BMP is an alternative that some older engraving software prefers because of its uncompressed simplicity.
- Resolution: 300-500 DPI at the engraveable area size.
- Color mode: grayscale. Convert to grayscale before submission.
- High contrast: adjust levels to maximize the contrast between light and dark areas.
- Clean edges: no anti-aliasing on text or sharp graphics intended for engraving.
- No transparency: raster engraving interprets white as no engraving and black as full power.
- Invert if needed: some software treats white as engrave and black as skip. Check your software's convention.
Material-Specific Considerations
Different materials respond differently to engraving, which affects artwork preparation.
- Wood: high contrast works best. Fine details below 0.5mm may not be visible. Test grain direction.
- Acrylic: very fine detail is possible. Both vector cut-through and surface raster engraving work well.
- Metal: requires specialized laser (fiber laser for bare metal, CO2 with marking compound for coated metal). Vector engraving produces the crispest results.
- Glass: raster engraving at lower power. Avoid very fine details that may cause glass to chip.
- Leather: both vector and raster work well. Test on a scrap piece first to calibrate power settings.
- Stone: raster engraving of photos works surprisingly well on polished stone.
CNC Router vs Laser Engraving
CNC routers use a physical cutting bit instead of a laser beam. The artwork requirements are similar but with additional constraints related to the bit's physical dimensions.
The minimum detail size is limited by the router bit diameter. A 1/8-inch bit cannot engrave details smaller than 1/8 inch. Inside corners will have a radius equal to the bit radius. Account for these physical limitations in your design.
- SVG or DXF for CNC vector toolpaths.
- Minimum feature size: equal to the router bit diameter.
- Inside corner radius: equal to half the bit diameter.
- Pocket depth must be specified (not just 2D path).
- Add dog-bone fillets to inside corners for parts that need to fit together.
Why JPG Fails for Engraving
JPG compression creates artifacts that directly translate to visible defects in engraved output. Around text and sharp edges, JPG creates blurry halos that the laser interprets as gradual power transitions instead of sharp on/off boundaries. The result is fuzzy text and soft edges on the engraved material.
For raster engraving of photographs, JPG's block artifacts (visible 8x8 pixel grid patterns) can create a subtle grid pattern in the engraved surface. This is especially visible on smooth materials like acrylic and polished metal.
Frequently Asked Questions
What file format do laser engravers use?
SVG for vector engraving and cutting. PNG or BMP for raster (image) engraving. Most laser engraving software also supports DXF, AI, and PDF for vector work. SVG is the most universally compatible open format.
What DPI should raster engraving artwork be?
300-500 DPI at the actual engraveable area size. Higher DPI provides finer detail but increases processing time. 300 DPI is sufficient for most engraving applications. 500 DPI for very fine detail on materials like acrylic.
Can I engrave a photograph onto wood?
Yes. Convert the photograph to grayscale, increase contrast, and export as PNG or BMP at 300+ DPI. The laser varies its power based on pixel brightness to create a grayscale reproduction on the wood surface. Results vary by wood type and grain.
Why should I convert text to outlines for engraving?
Engraving machines trace paths, not text. If your SVG contains live text, the engraving software must have the exact font installed to render it correctly. Converting text to outlines (paths) makes the file self-contained and ensures the text engraves exactly as designed.
Convert JPG to PNG for clean engraving