Image to SVG for Laser Cutting and Engraving – A Practical Guide
By the ZypCRM editorial team · · 6 min read
Laser machines work in two very different ways, and most failed jobs come from preparing the wrong kind of file. Vector operations (cut and score) follow paths, like a pen tracing a line. Raster operations (engrave) sweep back and forth across an area, firing the laser dot by dot, like an inkjet printer. A logo you want to cut out of plywood needs a clean vector. A photo of a pet you want to burn onto a cutting board needs a carefully prepared bitmap.
This guide covers both, using the Image to SVG for Laser tool, and explains the settings that matter in LightBurn, xTool Creative Space, Glowforge and similar software.
Part 1: Vectors for cutting and scoring
What makes a good cut file
A laser cuts exactly what the file says. That means:
- Closed paths. An open path cuts a line that does not meet itself, so the piece never drops out.
- No duplicate lines. Two identical paths on top of each other cut twice, which burns edges and can start flare-ups. Traced files avoid this by design, but files merged from several sources often have doubles.
- No tiny fragments. Each speck is a separate pierce point. Hundreds of them add time, heat and charring.
- Correct size. Lasers work in real units. A file intended as 100 mm wide must arrive as 100 mm wide.
Choosing the job type and style
In the laser tool, choose Cut or score – black & white vector (SVG / DXF). Then pick a style:
- Filled shapes (engrave/cut areas) produces solid shapes. In most laser software you can assign these to a fill or engrave layer (to engrave the area) or to a line layer (to cut around the outline).
- Outlines only (hairline, for cutting/scoring) produces thin strokes and no fill. This is what drivers that treat very thin strokes as vector cuts expect, and it is a clean choice for scoring designs onto material.
Use Threshold to decide where the black-and-white boundary falls. If thin parts of a logo vanish, raise it; if background shading turns into shapes, lower it.
Set Width (mm) to the finished size. The SVG is written in millimetres, and the Download DXF (mm) option gives you a DXF in millimetres for CAD-style workflows and software that prefers DXF over SVG.
Importing into your laser software
LightBurn: use File → Import (or drag the file in). Check the size readout in the toolbar against your intended width. Each colour in LightBurn is a layer with its own mode (Line, Fill, Offset Fill, Image). Set cut paths to Line mode. If something will not cut through, look for unclosed shapes with Edit → Select open shapes.
xTool Creative Space: import the SVG, then for each object choose Cut, Score or Engrave in the processing panel. Filled shapes default to engrave; switch them to cut if you want the outline cut.
Glowforge: upload the SVG. Glowforge separates operations by colour, so a single-colour file arrives as one step. If you want part of a design scored and part cut, prepare separate colours first (the Recolour & Split SVG tool can change colours inside an SVG).
Kerf and fit
The laser beam removes a small amount of material, called kerf, usually around 0.1–0.2 mm depending on the machine, lens and material. For decorative cut-outs this doesn’t matter. For parts that must fit together (box joints, inlays), you need to compensate with an offset in your laser software. Test on a scrap with a small square before committing an expensive sheet.
Part 2: Engraving photos
Why photos need dithering
A diode or CO₂ laser cannot burn “50% grey”. At each spot it either fires or doesn’t (some machines can vary power, but the results on wood are inconsistent). To show tones, the image has to be converted to patterns of black and white dots – this is dithering. Your eye blends the dots back into shades, just like a newspaper photo.
Choose Engrave a photo – dithered bitmap (PNG) and pick a dither method:
- Floyd–Steinberg (smooth tones): spreads the error of each dot onto its neighbours. Good general choice for portraits on light woods.
- Atkinson (crisper, higher contrast): spreads less of the error, so highlights and shadows stay cleaner. Often better for pets and high-contrast subjects, and on darker woods where midtones muddy.
- Ordered / Bayer (grid pattern, wood): a regular pattern that engraves very consistently, which helps on woods with strong grain where random patterns look blotchy.
- Threshold (no dither): pure black and white, for line art and silhouettes.
Brightness, contrast and the wood
Lasers darken material much more than you expect, especially in midtones, because adjacent burns spread. Most photos need to be lighter before engraving. Raise Gamma above 100 to lift the midtones without blowing out the highlights; for most woods, values around 120–180 work. Use Brightness for an overall shift, and increase Contrast slightly if the subject blends into the background.
For slate, black acrylic and anodised aluminium, the laser makes marks lighter than the surface, not darker. Tick Negative for these materials so the photo engraves the right way round.
Resolution
The Resolution setting sets how many dots per inch the PNG contains. It should match your engraving line interval in the laser software. As rough starting points:
- 254 DPI (0.1 mm line interval) is common on diode lasers on wood.
- 318 DPI (0.08 mm) suits finer materials and CO₂ lasers with small spot sizes.
- Going higher than the machine’s actual spot size only overlaps burns and darkens the image.
In LightBurn, set the layer to Image mode, set the line interval to match the DPI, and turn Pass-through on so LightBurn uses your dithered dots as-is instead of re-dithering them.
Get the best input photo
- Crop tightly and remove distracting backgrounds first (use the Remove Background tool).
- Choose photos with good light on the face and clear separation from the background.
- Avoid very dark photos – shadows become solid burnt areas.
Line drawings: a third option
Sometimes a photo looks better engraved as a drawing than as shaded tones. Photo to Line Drawing extracts the outlines of a picture, which engraves fast and looks crisp on almost any material. It is also a good starting point for vector scoring after tracing.
Test before you commit
Every material burns differently. A one-minute test on an offcut – a small square with your planned speed and power, and a strip of the actual engraving – saves the main piece. Note your settings for each material, because the “right” brightness for maple will be wrong for cherry.
Safety notes
Never cut PVC or vinyl in a laser: they release chlorine gas that damages lungs and machines. Be careful with unknown plastics and coated boards. Never leave a running laser unattended, and keep an extinguisher rated for your machine nearby.
Summary
- Cutting and scoring need closed vector paths at the correct size: use cut/score mode, choose filled or outline style, and export SVG or DXF in millimetres.
- Engraving photos needs a dithered bitmap: choose a dither style for the subject, lighten midtones, match the DPI to your line interval, and use Negative on dark materials.
- Always run a small test on the same material.