What Is Etching Ah and a Lhethography?

Gabriel ve: Some things are harder to etch than others, require really strong acids. Can you etch skin? I know there's a gallon of conductive tattoos in my college that can actually do that. What is photo lithography and how does it help miniaturize circuits? Gabriel Ve: Do you know what super acids are? i've never heard that term before but  it's just like if someone says they're going to use hydrochloric acid for something then the whole thing goes wrong.