I find that the highest resolution and lpi give the best result. That said, I cannot do a picture without some flaking at some density of the image. Vary the power and the greyness of the flaking area changes.

I have also done text by blasting away and leaving a carved look with no fracturing flakes.

Glass varies spot to spot. I even had an egg cup with a line of water glass in it. (The potash never made it to that spot in the mix. Leave out the potash and it dissolves in water.)

Philadelphia, PA (Really Bensalem)

When you finally understand it completely... it changes.