What DPI to use for laser engraving (quick guide by material and machine)

DPI in laser engraving confuses people because the term comes from printing, but it means something else physically here. It's not your image's quality — it's how many scan lines the laser makes per inch of material.

What DPI actually means in engraving

In raster engraving, the laser head makes horizontal back-and-forth passes, line by line, top to bottom. DPI defines how close together those lines are: at 300 DPI there are 300 lines per inch; at 150 DPI there's half that, with double the spacing between each line.

Some software (LightBurn included) calls the same thing "Line Interval" viewed the other way around: more DPI means a smaller interval between lines.

Why higher DPI isn't always better

Raising DPI isn't free, in two ways:

• Machine time. Doubling DPI roughly doubles engraving time, since there are twice as many lines to travel.
• Heat buildup. More lines per inch means more heat passes over the same area in less space. On wood this is a direct cause of burnt edges and warping — covered in why laser cutting comes out burnt at the edges.

At the same time, too low a DPI loses detail: dithering (see which dithering algorithm to choose) needs enough resolution to reproduce mid-tones, and below a certain point the image shows visible blocking.

Reference table by material and machine

Material	Laser type	Recommended DPI
Acrylic	CO₂	254
Anodized aluminum / MDF	CO₂	254
Anodized aluminum / MDF	Diode	318
Steel / Fiber	CO₂ or Fiber	400
Light wood (fine detail engraving)	Diode	318–400
Leather	Diode or CO₂	254

These numbers are reasonable starting points, not physical law — same as power and speed settings, the optimal DPI depends on your specific machine and how much detail the image has. A simple logo doesn't need the same DPI as a portrait with fine gradients.

How to choose without memorizing the table

A practical rule: start with the table value for your material/machine combination, and only raise it if the image has fine detail that's getting lost (portrait features, small text, thin lines). For logos, large text or simple illustrations, lowering DPI saves machine time with no visible loss.

If your image looks good at 254 DPI and you don't notice a difference bumping it to 400, stay at 254 — you'll engrave faster and with less heat buildup with no visible sacrifice.

DPI and dithering go together

DPI and the dithering algorithm aren't independent settings: a wide-diffusion dither (like Jarvis-JJN) needs somewhat more resolution to look clean than a regular pattern (Bayer), which holds up fine even at lower DPI. If you're raising DPI to gain detail, it's worth trying a different algorithm too before assuming the problem is purely resolution.

MEZ Laser comes with the recommended DPI pre-loaded based on the material and laser type you pick, and its test mode lets you compare several DPI values on the same image before engraving the good material.