PHOTO PREPARATION GUIDE · RASTERGO
Should you invert an image for slate engraving?
Updated October 2026 · Free browser tool · photos stay on your device
Invert only when your software and input image make the tonal mapping come out backwards. Export one normal and one inverted file and compare them on a test piece — that is faster and more reliable than following a universal rule.
Why advice conflicts
Two people can run the same slate and disagree about inversion, because the answer depends on how their laser software maps tonal values to laser power and on whether the source image is already light-on-dark. A rule that ignores both will be wrong half the time.
A two-export test
- Prepare the image once at the final size and DPI.
- Export a normal version and an inverted version with identical settings otherwise.
- Engrave both on the same scrap piece, side by side, at identical machine settings.
- Keep whichever reads with more detail in the face and mid-tones.
What to check on the result
- Mid-tones: inversion errors show up first as flat grey faces.
- Small text or edges: these are the first detail lost by the wrong mapping.
- Consistency: once you know the answer for your pipeline, write it down and reuse it.
The slate preview in RasterGo is a labelled digital simulation of material appearance, not a photograph of an engraved piece.
RasterGo prepares image files in your browser. Material previews are labelled digital simulations, not photographs of engraved pieces, and no power, speed or physical result is promised.