[Omega]

I read a thread on acid etching (but i cant remember by who ) in the post this individual used a special ink to write/draw his design then comes tha acid bath and he is left with a flat background and beautiful raised letters and designs. my question is what keeps the acid from eatting away at the side of the raised portions? im not sure im being totally clear but im just not sure how to explain the question any better


thanks

bill