A photo engraving on slate is one of the most rewarding results a laser delivers: a bright motif on dark stone, high contrast, permanent. It is also the process that depends most on the source image — and least on the machine.
The laser cannot do grey
That is the core. The laser head can remove material at a point or not remove it — there is nothing in between. A grey value therefore appears the same way it does in newspaper printing: through a halftone screen. Many dots close together read as dark, few far apart read as light.
Everything else follows from that. A motif with strong contrast translates well because the dot density varies markedly. A flat image where everything is a middling grey produces an evenly grey area — technically correct and utterly expressionless.
What makes a good source image
- Resolution: at least 300 dpi at final size. An image at 1200 × 900 pixels is enough for about 10 × 7.5 cm — not for an A4 plate.
- Contrast: clear differences between light and dark. When in doubt, pull the levels first.
- Motif: a face, an animal, a building — something with a clear shape. Group shots with twelve people lose every one of them.
- Background: quiet. A blurred, dark background lifts the subject; a colourful living-room background competes with it.
- Sharpness: the original, not the messenger-app copy of it. A compressed image brings artefacts that the screen makes visible.
Which materials work best
Slate is the favourite: the engraved area goes light, the untouched stone stays almost black — the greatest possible contrast, plus a surface that gives any motif character.
Anodised aluminium gives the technically cleanest result: the finest screen, no material texture interfering. Ideal for portraits that should look precise.
Pale wood — maple, birch, poplar plywood — is the warmest look. The grain mixes into the image; with quiet wood that is lovely, with strong grain it interferes.
Less suitable: dark solid wood (too little contrast), acrylic (the engraving goes white, which can look good but forgives no mistakes) and anything strongly grained or porous.
How we work
We prepare the image — crop, levels, screening method — and show you a preview of what the screen will look like beforehand. Only then does material go into the machine. For a gift with a deadline, that is the step that saves grief.
Everything on materials and file requirements is on the laser engraving page.