About this tool
Most diode lasers can only burn or not burn each dot. The gray tones of a photo are therefore made of many small dots placed closer together or further apart, just like in newspaper printing. This conversion is called dithering. How good a photo engraving looks depends mostly on resolution, contrast and method matching the material.
The tool scales your image to the wanted width in millimetres, with the resolution matching the line interval of your laser: 254 dpi is 0.1 mm. You adjust brightness, contrast and gamma, pick a dithering method and download a black and white PNG with the resolution stored in it. Everything happens in your browser, the image is not uploaded anywhere.
How it works
- Drop a photo or graphic into the field.
- Enter the width of the engraving in millimetres and the resolution that matches the line interval of your laser.
- Pick a dithering method and adjust brightness, contrast and gamma until the preview looks good.
- Download the PNG and import it into your laser software, with the same line interval and without dithering it again.
Frequently asked questions
Which resolution should I choose?
It should match the focus spot of your laser. For most diode lasers a line interval of 0.08 to 0.1 mm works well, about 254 to 318 dpi. If the interval is smaller than the spot, the dots overlap and the image gets dark and muddy.
Why does my engraving look too dark?
Wood and many other materials burn a little around each dot, so mid-tones come out darker than on screen. Raise gamma or brightness or lower the laser power. You can find the right power and speed with the Laser Test Grid Generator.
Which dithering method is best?
For photos Floyd–Steinberg is a good start, Jarvis and Stucki give smoother gradients. Atkinson looks crisper but loses detail in dark areas. For logos and text use the threshold, and lasers with variable power can use the gray levels directly.
When should I invert?
When the laser makes the material lighter instead of darker, for example on slate, black anodised aluminium or painted surfaces. It can also be needed when engraving the back of glass or mirrors; mirror the image in your laser software as well then.