No, 0.14 would only be 14%.
He used the method of scratching into a copper sheet. It is called Intaglio. Intaglio is a technique in printmaking. Copper and zinc are the two materials that are normally used with this kind of medium. Another example of this are collagraphs.
They are hidden in the corner of you're brain. Get creative and they will pop out :) it has happen to me before
