What natural pigment actually costs a mural painter

Five colours, all of them mineral or vegetable: red and yellow ochre, lamp black, white from lime, and green from the leaves of the eravikkara. Each is ground on a flat stone with water and gum, a little at a time, until it moves without grain. Red ochre goes quickly. Green cannot be hurried at all — worked too fast it dries dull, and the whole batch is wasted. Four days, before a brush touches a surface. He will not substitute a manufactured pigment. Asked why, when nobody could tell on the first day, he says the difference is visible after ten years. That is the kind of answer that explains a price better than any amount of marketing copy.