Lithography

Let the "Etching" Begin!

So when you put the etch on the stone and drawing (we don't show the gum arabic or nitric), the water goes to the surface of the stone and also mixes in with the drawing medium. Yes, we know we said the oil doesn't like water and that's true. But a little water does move into the oil or at least comes into contact with it at the oil and water surfaces.

What will happen now is the acid reacts with the limestone which liberates carbon dioxide. The surface alters to become even more water friendly.

Then water (with the acid) that is in contact with the vegetable oil will react to hydrolyze the oil. That is it breaks the oil down to form 1) free fatty acids and 2) glycerin.

To continyeh (as a former US president would say), click here.