Hi,
I'm building a laser engraver.
I'd like to engrave grayscale pictures.
To build the 
ngc-file I'm using 
inkscape ( what else ).
The graffiti/ 
spraygun option in 
Gcodetools seems the right choice.
Nevertheless 
grayscale is not translated to S-values.
I need these values because my laser uses the spindle speed as reference for its intensity.
Does anyone know where I can find documentation/ solution concerning this issue ?