Laser engraver file formats come down to one simple rule: machines want vector files such as SVG, DXF, or AI for cutting, and bitmap files such as PNG or JPG for engraving photos and shaded artwork. A vector file stores shapes as lines and curves the machine can follow with the cutting beam. A bitmap stores a grid of colored dots the machine burns line by line, like a printer. Pick the wrong type and the job goes sideways: photo engraving comes out flat and gray, or a cut line follows a hidden duplicate path and ruins the sheet. This guide explains what each format actually does, where SVG, DXF, and AI differ in daily use, how to prepare a photo so it engraves with real depth, and the export settings that prevent the most common surprises.

Vectors for cutting, bitmaps for engraving

Before naming formats, it helps to know the two families they belong to. A vector file describes artwork as math: a circle is a center point plus a radius, a letter is a series of connected curves. Because the shapes are pure geometry, the laser software can send the beam along those exact paths at any size with no loss of quality. That is why every cutting job should start as a vector. When you cut, the machine follows the outline of each shape with the beam at full power.

A bitmap (also called a raster image) works completely differently. It is a fixed grid of pixels, and each pixel holds a color or shade. The engraver reads that grid row by row and turns each dark pixel into a burn dot, which is exactly what you want for photographs, shaded logos, and painted art. Engraving mode uses the bitmap's gray levels to vary power, so dark areas burn deep and light areas stay faint.

The classic beginner mistake is giving a cutting job a bitmap, or giving a photo job a vector. If you import a PNG of a logo and ask the machine to cut it, the software traces a jagged staircase outline around the pixels and the cut edge looks rough. If you engrave a vector logo as-is, you often get just the outlines burned instead of solid shapes. Knowing which family your file belongs to solves most format confusion before it starts.

SVG, DXF, and AI: what actually differs

All three are vector formats, but they come from different worlds and behave differently once they reach your laser software. SVG (Scalable Vector Graphics) is the open web standard, and it is the safest default. It stores shapes, layers, and colors in plain text, so nearly every laser program from LightBurn to the free vendor tools reads it cleanly. SVG also remembers document size in real units, which keeps your 100 mm keychain from arriving as a 100 pixel speck. Its main quirk: some design apps export SVG with the page sized in pixels at 96 dots per inch, so always confirm the physical size after import.

DXF is the old CAD exchange format, and it is what most industrial and CNC-focused tools expect. Its strength is universal support: every CAD package on earth can write one. Its weakness is that basic DXF carries no reliable unit information and ignores fills, images, and many modern layer features. A DXF of a circle knows the curve but not that you wanted it cut 120 mm wide, so size errors are common. When you export DXF, pick a recent version like R12 or newer, set units explicitly, and double-check dimensions in the laser software before running.

AI is Adobe Illustrator's native format. It is rich and precise, but it is a closed format that many laser programs cannot open directly. The practical workflow is to keep your master file as AI and export a copy as SVG or DXF for the laser. Never send the only copy of a design through conversion; keep the original untouched so edits stay easy later.

One more note on layers. SVG and AI files can carry layer names, and good laser software lets you assign a different power and speed to each layer. Putting cut lines on one layer and engraving fills on another is the single biggest workflow upgrade a new owner can make, because the machine then runs both steps in one job without manual re-sorting.

Photo files and dithering prep

Photos engrave from bitmaps, but a raw phone photo will not look good on wood or slate without preparation. The laser can only burn or not burn at each dot; it cannot print true gray. Dithering is the trick that fakes gray shades: the software converts smooth tones into patterns of tiny dots of different size and spacing, the same way old newspaper photos worked. Your laser software usually applies dithering automatically, but you still need to feed it a clean image.

Start with the highest resolution photo you have, ideally around 300 dots per inch at the final engrave size. A 500 pixel-wide photo stretched to 200 mm will look soft and muddy. Convert the photo to grayscale first, then boost the contrast so the subject separates from the background. Washed-out photos engrave washed-out.

Background choice matters more than beginners expect. Light wood and slate burn dark, so the photo often needs to be inverted (flipped to a negative) before engraving, which makes highlights burn light and shadows burn dark. Test on scrap, and if faces look hollow, invert and try again. Remove busy backgrounds with a free cutout tool before engraving portraits; the laser will happily burn every pixel you leave in, including clutter you never noticed.

Common export mistakes

Most "my laser is broken" moments trace back to one of a handful of export mistakes. Checking this list before every job takes thirty seconds and saves sheets of scrap.

Wrong units are the top offender. Design apps often work in pixels while laser software expects millimeters, so a logo designed at 1000 pixels wide arrives as 1000 millimeters wide and slams the machine rails. Always confirm the physical size in the laser software before framing.

The second mistake is text left as live text instead of converted to paths. If the computer receiving the file does not have your font installed, the software substitutes a different one and your layout falls apart. Converting text to curves (in Illustrator: Create Outlines; in Inkscape: Object to Path) freezes letters as shapes forever.

Third is stroke versus fill confusion. Laser software usually cuts along a path's stroke and engraves its fill, so a shape with both may get cut and engraved in one pass. Set cut lines to a hairline stroke (around 0.1 mm, sometimes labeled 0.001 inch) with no fill, and set engraving shapes to fill with no stroke.

Fourth are hidden duplicates and open shapes. A path duplicated by accident gets cut twice in the same spot, scorching the edge. A shape whose outline does not fully close will not cut a clean part. Most laser programs highlight duplicates and open paths; learn where that check lives and use it.

Finally, watch the artboard. Designers often leave a large canvas around small artwork, and some importers scale artwork to fit the page, silently resizing your job. Crop the artboard close to the design before export.

How to prepare a cut-ready file

Here is a repeatable routine that works in Inkscape (free), Illustrator, or Affinity Designer. Follow it in order and your files will run right the first time.

1. Set the document units to millimeters and draw a reference rectangle the exact size of your material, for example 300 by 200 mm. This anchors every size decision that follows.
2. Draw or place your artwork inside that rectangle at final size. Avoid designing large and scaling down later, because line weights and minimum details change with scale.
3. Convert all text to paths so fonts can never be substituted on another computer.
4. Separate jobs by layer: one layer for cut lines, one for surface engraving, one for deep engraving. Name them clearly, because your laser software will show those names.
5. Style the cut layer with a hairline stroke (0.1 mm or less) in pure red or blue with no fill. Style engraving shapes as fills with no stroke.
6. Check for problems: remove duplicate paths, close any open outlines, and delete stray points left from tracing.
7. Export. For cutting and layered jobs choose SVG with units in millimeters; for CAD-heavy work or a stubborn importer choose DXF with explicit units. Keep the master design file unconverted.
8. In the laser software, re-check the imported size against your reference rectangle, confirm each layer got the right power and speed setting, then frame the job before pressing start.

Once this routine is muscle memory, file preparation drops from ten minutes of guessing to two minutes of checking.

Common questions (FAQ)

What file format do laser engravers use?

Most laser engravers accept SVG, DXF, AI, and EPS vector files for cutting, plus PNG, JPG, and BMP bitmaps for photo engraving. SVG is the best all-around choice because it is open, keeps real-world sizes, and every major laser program supports it. Your machine's own software converts whichever file you give it into the movement instructions the laser follows.

Is SVG or DXF better for laser cutting?

For hobby and small-business machines, SVG is usually better because it preserves layers, colors, and document size reliably. DXF makes sense when you work from CAD software or your laser tool has weak SVG support, but basic DXF loses unit information and layer styling. If you must use DXF, export a recent version with units set explicitly and verify the size after import.

Why is my SVG cutting wrong size?

Nine times out of ten it is a units mismatch: the design app exported the page in pixels while the laser software read it as millimeters, or vice versa. Check the imported size against your intended dimensions before running the job. The fix is to set your design document to millimeters from the start and confirm the artboard size matches the artwork, not the other way around.

Related reading

File formats are only half the workflow; the other half is choosing a machine that cuts the materials your products need. If you are comparing cutters for a small shop, our overview of the fiber laser cutter covers the industrial side of that decision, and the HF laser cutter page at https://www.hflaser.com/laser-cutter.html walks through cutting machines suited to sheet metal and production work. Reading both before you buy makes the software questions in this guide much easier to answer, because a machine matched to your materials rarely forces format workarounds.