Raster vs Vector Laser Engraving: Which Mode to Use
Raster engraving scans line-by-line like a printer, filling areas pixel-by-pixel. Most 10W diode lasers work best at 254 DPI (a 0.10 mm line interval that matches the beam size). Vector engraving traces a path and is 5–15× faster for outlines and text edges. In LightBurn, Fill = raster and Line = vector. For photos or solid fills, use Fill. For outlines, text edges, or cutting, use Line.
| Task | Use this mode | LightBurn layer |
|---|---|---|
| Photo or portrait engraving | Raster | Fill |
| Solid filled logo or text | Raster + outline | Fill or Fill+Line |
| Outline / text edge / line art | Vector | Line |
| Cutting any shape | Vector | Line |
- Raster-filling a 50 × 50 mm square at 254 DPI takes roughly 8 minutes on a 10W laser; tracing the same square's outline in vector mode takes under 30 seconds.
- "Fill" = raster, "Line" = vector in LightBurn — mixing them up is the single most common setup mistake for new users.
- Bidirectional raster (bi-dir) is roughly 2× faster than unidirectional but requires a scanning offset calibration to prevent horizontal line shift.
- For cutting, always use vector (Line mode). Raster cutting is technically possible but wastes time scanning empty space between passes.
"Raster-filling a 50 × 50 mm square at 254 DPI takes about 8 minutes on a 10W laser; tracing the same square's outline in vector mode takes under 30 seconds. — Laser Tinkerer, 2026"
What is raster laser engraving?
Raster engraving works exactly like an inkjet printer: the laser head sweeps back and forth in a series of horizontal lines, firing the laser on and off to reproduce the image pixel by pixel. Each pass moves the gantry a tiny step in the Y direction before the next line begins. The spacing between lines is determined by the DPI setting — at 254 DPI, adjacent lines are 0.10 mm apart, which matches the beam size of most 10W diode lasers.
The result is a filled, engraved area — a photo, a filled logo, a solid text block. Raster is the only mode that can reproduce grayscale (by varying power or speed across the image) or fill complex shapes. It cannot, however, do anything faster than scan every line in the image bounding box, even the empty areas in between.
How DPI affects raster quality and speed
| DPI | Line interval | Typical result | Speed impact |
|---|---|---|---|
| 127 | 0.20 mm | Visible gaps between lines; coarse texture | Fastest — fewest lines |
| 254 ★ | 0.10 mm | Clean fill; matches most 10W beam width | Best quality–speed balance |
| 500 | 0.05 mm | Adjacent lines overlap; darker, slower, may over-burn | ~2× slower than 254 DPI |
| 1000 | 0.025 mm | Heavy overlap; rarely beneficial for diode lasers | ~4× slower than 254 DPI |
The 254 DPI sweet spot is not arbitrary — it corresponds to one line per 0.10 mm, which is roughly the minor-axis beam width of a focused 10W diode module. Running higher DPI does not inherently improve quality if the beam is wider than the line spacing; it mostly adds heat and time. See the DPI settings guide for a deeper look at how beam size and line interval interact.
What is vector laser engraving and cutting?
Vector engraving (and vector cutting) traces the actual path of a shape — an outline, a curve, a set of lines — the same way a plotter draws with a pen. The laser moves along the defined path at a constant speed, burning into the material wherever the path goes. There are no horizontal sweeps; the laser only travels where the art is.
This makes vector operations dramatically faster for anything path-like: the outline of a word, the score lines of a box joint, a monogram on a cutting board, or any cutting job. A letter that would take 4 minutes to raster-fill can have its outline traced in under 15 seconds in vector mode.
Vector engraving vs vector cutting: the same mode, different depth
In LightBurn, "Line" mode handles both engraving and cutting — they differ only in power and passes. A 10W laser at 30% power tracing a path lightly is a vector engrave (a surface mark, like scoring). The same machine at 85% power with 2–3 slow passes is vector cutting (all the way through). The path-tracing logic is identical; only the settings change.
$32=1) and use M4 (not M3) to prevent burned, overcut corners in vector jobs. See the dark corners guide for the full setup.
How to choose: a decision table
Below is the pattern that covers most practical laser projects. When in doubt: if you can see the shape as a filled area → raster; if you can see it as a set of lines or outlines → vector.
| What you're making | Mode to use | LightBurn layer | Why |
|---|---|---|---|
| Photo or portrait on wood | Raster | Fill | Only raster can reproduce grayscale shading |
| Solid filled logo or graphic | Raster | Fill | Interior must be filled line by line |
| Filled text (bold letters) | Raster + outline | Fill+Line | Raster fills the interior; Line sharpens the edges |
| Outline-only text or script | Vector | Line | 5–15× faster; follows the actual letterform path |
| Engrave a border or line drawing | Vector | Line | Line art is already a set of paths; no fill needed |
| Cut a shape (any material) | Vector | Line | Only vector cutting is practical at full depth |
| Score/fold lines in cardboard | Vector | Line | Low-power trace along the fold; fast and precise |
| Personalise a cutting board (monogram) | Raster or Fill+Line | Fill or Fill+Line | Solid letters look best with Fill; add Line for crisp edge |
Raster settings in LightBurn (the Fill layer)
When you set a layer to "Fill" in LightBurn, these are the settings that control the result on a 10W–40W diode laser:
DPI and line interval
This is the single most important raster setting. Set it once per machine, leave it there. For most 10W diode modules: start at 254 DPI. If you see visible gaps between lines, lower DPI or try 318 DPI (0.08 mm). If lines are heavy and overlapping, raise DPI or use a faster speed. The DPI settings guide walks through the test procedure.
Scan direction: unidirectional vs bidirectional
Unidirectional (uni-dir): the laser only fires on the left-to-right passes. The head returns to the left edge with the laser off. Slower (roughly half the fill speed), but there is no potential for horizontal shift between adjacent lines. Best for test engraves and any time you notice scanning offset problems.
Bidirectional (bi-dir): the laser fires on both directions — left-to-right and right-to-left. Roughly 2× faster, which makes a real difference on large fills. The trade-off is that a slight mechanical backlash or firmware timing difference between the two directions can cause adjacent lines to be shifted horizontally, creating a feathered or double-image look in fine detail. This is called scanning offset. See the scanning offset section below for how to calibrate it.
Overscan
Enable overscanning in LightBurn (typically set to 2.5% or 2–3 mm). Without it, the laser fires while the head is still accelerating or decelerating at the start and end of each scan line, delivering too much energy to the edges of the engraving. Overscan extends each pass by a few millimetres (with the laser off), ensuring the head is at full speed before the laser turns on. This is also why GRBL laser mode ($32=1) matters — it prevents the laser from firing at reduced power during the accelerating end sections. See the quality troubleshooting guide for a detailed explanation of burned edges.
Power and speed for raster (10W to 40W reference)
| Machine optical wattage | Material | Power | Speed | DPI |
|---|---|---|---|---|
| 10W | Basswood / birch plywood | 55–70% | 2,500–3,500 mm/min (42–58 mm/s) | 254 |
| 20W | Basswood / birch plywood | 30–45% | 3,000–5,000 mm/min (50–83 mm/s) | 254 |
| 40W | Basswood / birch plywood | 20–35% | 4,000–7,000 mm/min (67–117 mm/s) | 254 |
These are starting points sourced and normalised from community and manufacturer data. Always confirm with a test grid. Confidence: medium (community-verified ranges).
Vector settings in LightBurn (the Line layer)
When a layer is set to "Line" in LightBurn, the key settings are speed, minimum power, maximum power, and number of passes. These work together very differently from raster settings.
Speed and power for vector engraving
Vector engraving (a surface mark, not cutting through) is faster and lower-power than cutting. On a 10W laser: for decorative outlines on basswood or birch, start at 30–40% power and 2,000–3,000 mm/min (33–50 mm/s). Adjust until the mark depth looks right. There is no DPI setting — the line width is determined by the beam width and focus.
Minimum power
This is the power level at corners, where the laser head slows down. In M4 (dynamic) mode, LightBurn scales power proportionally to speed between the minimum and maximum. Set minimum power to roughly 5–15% for most engraving work — enough to prevent a cold start but low enough to avoid burned corners. Do not set minimum power to 0% if you need continuous marks through corners (the laser would briefly turn off).
Passes for vector cutting
Vector cutting uses multiple passes at lower speed and higher power. Each pass deepens the cut. Fewer, slower, more powerful passes generally produce cleaner edges than many fast passes — see the single vs multi pass guide for the full data-backed decision. For cutting, add kerf compensation (offset) to the Line layer if your cut pieces are slightly too large or small — see the kerf compensation guide.
Vector cutting reference (10W to 40W)
| Machine | Material / thickness | Power | Speed | Passes |
|---|---|---|---|---|
| 10W | 3 mm basswood | 85–95% | 500–700 mm/min (8–12 mm/s) | 2–3 |
| 20W | 3 mm basswood | 70–85% | 800–1,200 mm/min (13–20 mm/s) | 1–2 |
| 40W | 3 mm basswood | 50–70% | 1,500–2,500 mm/min (25–42 mm/s) | 1 |
Starting points — confirm with a test cut. With air assist, you may be able to reduce passes by one. See the basswood settings page and 3 mm plywood cutting page for full sourced tables.
Combining Fill and Line in one job
Most real projects use both modes together. A personalised cutting board might have a raster-filled monogram (Fill layer) plus a vector-cut outline to trim the board to shape (Line layer). A wooden sign might have a raster logo (Fill) and a vector border (Line). LightBurn makes this straightforward: you assign each layer a mode, and LightBurn runs them in order.
The typical workflow
- Import or create your artwork. Bitmap images (PNG, JPG) will always become Fill layers. Vector paths (SVG, DXF, AI) can be Fill, Line, or Fill+Line depending on what you need.
- In the Layers panel, click the mode selector (the icon that says "Fill" or "Line") for each layer and choose the correct mode.
- For a shape you want both filled and outlined, set the layer to Fill+Line. LightBurn raster-fills the shape first, then traces the outline in the same layer pass.
- Set power and speed separately for Fill layers (raster settings) and Line layers (vector settings). They will typically be very different values.
- Layer order in the Cuts / Layers panel matters for cutting: process inner cuts before outer cuts so the workpiece remains registered. LightBurn has an "Optimize" setting for this.
Fixing bidirectional raster shift (scanning offset)
If your bidirectional raster engravings look like they have a subtle horizontal ghost or the vertical edges of a shape look feathered, you have a scanning offset problem. In bidirectional mode, the laser fires on both the outward and return passes. Even a 0.1–0.2 mm difference in trigger timing between the two directions produces visible misalignment in fine detail.
How to calibrate scanning offset in LightBurn
- Go to Edit → Machine Settings → Scanning Offset Adjust (for GRBL-based machines; the exact path varies by firmware).
- Set your working scan speed (e.g., 3,000 mm/min) in the field and click "Generate Test" to create a calibration pattern. This burns a series of vertical lines in both directions at that speed.
- Measure the horizontal shift between the odd and even lines with a digital calliper or a loupe. Enter the measured value (in mm) as the correction for that speed.
- Repeat for any other speeds you commonly use — offset is speed-dependent and must be calibrated per speed.
- Re-engrave the test pattern to confirm the lines are now aligned. If they are, bidirectional mode is safe to use at that speed.
If scanning offset calibration is too fiddly or you rarely need the speed advantage, switching to unidirectional mode is a reliable fallback. It is slower but always free of horizontal shift.
Common mistakes with raster and vector modes
| Mistake | What you see | Fix |
|---|---|---|
| Using Fill (raster) to "cut" a shape | Extremely slow; charred edges from scanning empty space; rarely cuts through | Switch to Line (vector) for all cutting. Raster cutting is almost never the right approach. |
| Assigning a photo to a Line layer | LightBurn traces a vector path around every pixel group; jagged outlines, slow, incorrect result | Bitmap images must always use Fill (raster). Only SVG/DXF vector art belongs on Line layers. |
| Running DPI too high (500–1000) for speed | Darker but slower result; adjacent lines overlap, increasing heat and blurring detail | Start at 254 DPI. Higher DPI only helps if your beam is smaller than 0.10 mm (most diodes are not). |
| Overscan disabled in raster mode | Burned / darker edges at the left and right boundaries of every engraved shape | Enable overscan in LightBurn (2–3 mm). Also enable $32=1 laser mode and M4. |
| Setting minimum power to 0% in vector mode | Laser briefly turns off at corners; gaps or lighter spots at every direction change | Set minimum power to 5–15%. The laser dims at corners rather than turning off completely. |
| Processing outer cuts before inner cuts | The workpiece shifts after the outer cut; inner details are cut out of position | In LightBurn, use "Optimize" (cut inner shapes first) or manually order your layers so inner paths are above outer paths in the Cuts panel. |
Gear for raster and vector work
The main hardware cost is the laser itself. For practice material while you learn settings and modes, a few inexpensive items help:
- Basswood sheet pack — the best test material for both raster and vector work. Consistent grain, engraves cleanly, cuts in 2–3 passes at 10W.
- Honeycomb work bed — keeps material flat (critical for consistent raster engraving depth) and allows air to circulate under cut pieces.
- OD7+ 450 nm safety glasses — required whenever the laser is powered, for both engraving and cutting operations.
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Frequently asked questions
Should I use raster or vector to engrave text on wood?
For bold filled text (where the interior of each letter is solid), use Fill (raster) or Fill+Line. For outline-only text or script lettering where a single path traces the letter, use Line (vector). Fill+Line gives the clearest result for most signage work: the raster fill engraves the interior first, then the vector outline traces the edges to sharpen them. For very small text (under about 10 mm tall), raster fill can blur at coarse DPI — try vector engraving or fine-tune to 318 DPI.
What is the difference between Fill and Line in LightBurn?
Fill runs raster engraving — the laser head sweeps back and forth across the shape, filling it line by line like a printer. Line runs vector engraving or cutting — the laser traces the actual path (outline, curve, or line) of the shape. Fill is used for photos, filled graphics, and solid text. Line is used for outlines, cutting shapes, and any art that is already defined by paths rather than filled areas.
Is vector engraving faster than raster?
For outlines and text edges, yes — significantly. Raster-filling a 50 × 50 mm square at 254 DPI takes around 8 minutes on a 10W laser; tracing the same square's outline in vector mode takes under 30 seconds. However, this is not an apples-to-apples comparison: vector traces only the outline; raster fills the interior. If you need the interior filled, you cannot replace raster with vector. For photos or solid filled shapes, raster is the only option regardless of speed.
Why does my bidirectional raster engraving look like zigzag lines or double-image?
This is a scanning offset (backlash) problem. In bidirectional mode, a slight difference in trigger timing between the left-to-right and right-to-left passes shifts the even lines horizontally relative to the odd lines, creating a feathered or ghost-image appearance in fine detail. Fix it in LightBurn under Edit → Machine Settings → Scanning Offset Adjust: run the calibration test at your working speed, measure the shift, and enter the correction. If calibration is too fiddly, switch to unidirectional mode instead.
Can I mix raster and vector engraving in one LightBurn job?
Yes — and this is the normal workflow for most projects. Assign Fill layers for areas you want raster-engraved (photos, filled logos, solid text bodies) and Line layers for outlines, borders, and cutting. Use Fill+Line on a single layer for shapes you want both filled and outlined. LightBurn processes all Fill layers before Line layers by default, which is the correct order: fill the interior, then trace the crisp outline over it.
Settings are calibrated starting points sourced and attributed as described on the methodology page. Results vary by machine, material batch, and ambient conditions. Always confirm with a test before committing to a full job. Last verified 2026-07-05 — Laser Tinkerer.