Raster vs Vector Laser Engraving: File Prep, Modes, and When to Use Each

Every laser job boils down to one of two fundamentally different operations — raster engraving or vector cutting/scoring — and mixing up how you prepare a file for each is the single most common reason beginners get muddy engraves, missed cuts, or jobs that take three times longer than they should. This guide breaks down exactly what raster and vector mode are doing at the hardware level, how to prepare files correctly for each, and how to combine them in a single job without fighting your software.

What's Actually Different

Raster engraving works like an inkjet printer: the laser head sweeps back and forth in horizontal lines across the material, pulsing power on and off (or modulating power continuously) to burn a grayscale image into the surface one line at a time. Vector cutting or scoring works like a plotter: the laser head follows a continuous path defined by lines and curves, at constant power and speed, either cutting all the way through the material or scoring a line into the surface. The two modes use completely different toolpaths, different settings, and different file types under the hood, even when your laser software lets you mix both in one job.

Raster Engraving: File Prep

• Use image formats for image content. Photos, logos with gradients, and anything with shading should be raster (PNG, JPG, BMP) — not converted to vector paths, which can't represent grayscale shading.
• Convert to grayscale and check contrast before sending to the laser. The laser maps pixel brightness to burn depth/darkness (darker pixel = more power/slower travel in most software). Low-contrast source images produce muddy, flat-looking engraves — boost contrast in an image editor first.
• Dithering matters for photo-realistic engraves. Most laser software (LightBurn, LaserGRBL) offers dithering algorithms (Jarvis, Stucki, Floyd-Steinberg) that simulate grayscale using patterns of dots at fixed power — this generally looks better on wood and other materials than a smooth grayscale gradient, which can produce visible power-step banding on some machines.
• Resolution/DPI sets your line spacing. Higher DPI (more lines per inch) gives finer detail and smoother gradients but takes proportionally longer to run. 300-500 DPI is a common sweet spot for detailed photo engraving on wood; simple logos can run acceptably at 150-200 DPI in a fraction of the time.
• Scan direction and overscan. Unidirectional scanning (laser only fires on one pass direction) gives cleaner edges at the cost of speed; bidirectional scanning is faster but can show slight banding if your machine's timing isn't perfectly tuned. Overscan (extra travel distance past the image edge) lets the head reach constant speed before the laser fires, avoiding the classic "dark edge" artifact from acceleration at the start of each line.

Vector Cutting/Scoring: File Prep

• Use true vector formats. SVG, DXF, and AI files preserve the actual path geometry your laser software needs — never rasterize a cut file to a bitmap and try to trace it back to vectors if you can help it, since you'll lose precision at every curve.
• Close your paths. An open path (a line that doesn't return to its start point) will often confuse cut-mode detection in laser software, either getting treated as an engrave line or leaving a small uncut tab. Check for open paths before sending to the laser, especially in files imported from Illustrator or Inkscape where a stray click can break a path.
• Color-code operations, not just geometry. LightBurn and similar software assign cut/score/engrave settings by line color (or layer). A design with cut lines in red, score lines in blue, and engrave fills in black is standard practice and lets you set power/speed once per color rather than per object.
• Account for kerf. The laser removes a small width of material as it cuts (kerf), typically 0.1-0.3mm depending on power, speed, and material. For interlocking joints (finger joints, tab-and-slot), either compensate the design for kerf directly or run a quick kerf calibration test cut on scrap material of the same thickness before cutting your final parts.
• Nest paths to minimize travel and heat buildup. Order and group cuts so the laser isn't jumping across the whole sheet repeatedly, and consider cutting from center-out on large sheets to reduce warping from thermal buildup, especially on acrylic.

Combining Both in One Job

TaskRecommended orderWhy Engrave a logo, then cut the outlineEngrave first, cut lastCutting last means the part isn't loose and shifting during the more precise engrave pass Score fold lines, then cutScore first, cut lastSame reasoning — keep the part fixed in the bed during the operation that needs the most positional accuracy Multiple engrave passes at different depthsDeepest/darkest pass lastMinimizes smoke residue re-deposit affecting a lighter subsequent pass

Common Mistakes

• Sending a photo as a vector trace. Auto-tracing a photo into vector paths and cutting/scoring it produces a crude line-art outline, not a photo-quality result — that's a raster job.
• Forgetting to remove the raster background behind vector art. If your source file has a white or colored background layer, some software will try to engrave it as a raster fill you didn't intend — delete or hide background layers before sending the job.
• Using engrave power settings for a cut, or vice versa. These are separate settings for a reason — a raster power/speed setting applied to a cut path will either fail to cut through or torch straight through in an uncontrolled way. Always check which mode a layer is assigned to before running the job.

Closing Thoughts

Once raster and vector click as genuinely separate operations — not just two menu options in the same software — file prep for either one gets a lot more intuitive. Spend a few minutes checking image contrast before a raster job and checking for open paths before a vector job, and you'll eliminate the majority of "why did this come out wrong" laser mistakes before they ever hit the machine.