# QR codes on wood: grain, species and laser settings

> Wood grain competes with module edges, so engrave with modules at 1 mm or larger and choose pale, fine-grained species: maple and birch char to a dark, even mark, while walnut is too dark for good contrast and pine burns unevenly around resin. Seal outdoor pieces, because bare char weathers to grey.

Source: https://useqr.app/docs/print/qr-codes-on-wood · Last reviewed 2026-08-21 · UseQR is free forever, no signup.

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## Grain is structured noise

Wood is not a uniform substrate. Each growth ring alternates soft, pale earlywood with
denser latewood, and the two burn differently under a laser: the same power that chars
earlywood a rich brown may barely darken a latewood band. The result is a code whose "dark"
modules vary in darkness along the grain: structured noise aligned in stripes, which is
harder on a decoder than random speckle. Open-grained species add pores and vessel lines
that read as false light pixels inside dark modules.

The defence is scale: keep engraved modules at **1 mm or larger** so each module spans
several grain features and averages out. That floor comes from the
[size-for-print table](/docs/print/qr-code-size-for-print); at 1 mm a version 3 code with
[quiet zone](/glossary/quiet-zone) is a 37 mm square. Shorten payloads before shrinking
modules, and check with the [size calculator](/size-calculator).

## Species selection, ranked for contrast

| Species | Base colour | Char behaviour | Verdict |
|---|---|---|---|
| Maple | Pale, fine grain | Dark, even char | **Best all-rounder** |
| Birch (incl. Baltic birch ply) | Pale, fine grain | Even char | Excellent, cheap |
| Alder | Light tan | Very dark char at low power | Excellent |
| Cherry | Light red-brown | Good char, ages darker | Good, contrast narrows as it ages |
| Oak | Medium, open grain | Even char, but pores speckle | Usable at 1.2 mm+ modules |
| Pine / spruce | Pale | **Uneven**, resin pockets flare and blotch | Avoid for codes |
| Walnut | Dark brown | Char barely darker than base | **Poor**, contrast below threshold |

The pattern: you want a **light wood that chars dark**. Dark species fail not because they
engrave badly but because dark-on-dark violates the
[contrast requirement](/glossary/contrast-ratio). On walnut, the honest options are an
engraved recess with light paint infill (inverting polarity: avoid), a bonded maple inlay,
or printing instead of engraving, the trade-offs live on
[etched vs printed](/docs/print/qr-codes-etched-vs-printed).

## Engraving settings that matter

- **Raster-engrave the modules as filled areas**; do not vector-outline them.
- Aim for surface char, not depth. Deep engraving adds shadows and fuzzy carbonised edges
  without adding contrast.
- A slight defocus broadens the beam and evens the burn on ringy species.
- Masking tape over the face prevents smoke staining the light modules, smoke residue in
  the quiet zone is a real contrast thief.
- MDF and veneered plywood char very consistently (no grain rings), making them the
  pragmatic choice for signage even if solid timber looks better.

An alternative that skips burning entirely: UV flatbed printing puts true black ink on
wood with print-grade edges. It wins on contrast, loses on lifespan and the engraved look.

## Outdoors: seal it or lose it

Char is carbon sitting in burnt fibres, and weather strips it. UV greys the surrounding
wood (the driftwood effect) while rain and frost erode the charred layer, so contrast
collapses from both directions, the general decay pattern described in
[outdoor durability](/docs/print/qr-codes-outdoors-durability) and
[UV fading](/docs/print/uv-fading-and-qr-codes). Seal finished pieces with a **clear matt
exterior varnish or oil**: matt, because gloss adds
[glare](/docs/print/qr-codes-on-glossy-surfaces-and-glare), and expect to re-coat
annually for anything permanently outside. For garden and trail signage that must last
years unattended, engraved wood is the wrong answer; use
[metal](/docs/print/qr-codes-on-metal).

Buying guidance and project ideas are on [laser-cut wood](/qr-codes-on/laser-cut-wood) and
[how to engrave a QR code](/docs/how-to/how-to-engrave-a-qr-code).

## FAQ

### What wood is best for a laser-engraved QR code?
Maple, birch and alder: pale, fine-grained species that char dark and evenly. Avoid walnut (too dark for contrast) and pine (resin pockets burn unevenly). MDF and birch ply are the most consistent budget options.

### How small can an engraved QR code be on wood?
Keep modules at 1 mm or larger so each module spans several grain features. A short-URL version 3 code at 1 mm is roughly a 37 mm square including the quiet zone.

### Do wooden QR codes work outdoors?
Only sealed. Bare char erodes and the surrounding wood greys under UV, so contrast fails from both sides. Use clear matt exterior varnish, re-coat regularly, and for multi-year unattended signage choose metal instead.

### Why is my engraved QR code patchy?
Grain. Earlywood and latewood char at different rates, so module darkness varies in stripes. Increase module size, reduce power and slow the pass for an even surface char, or switch to a finer-grained species.

## Try it

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