in its raw form: indigo dye
Indigo dye is one of the most startling, inspiring natural dyes, it seems to me. Just found these pictures in an article about the intricate dye-making process, shot by Marie Clérin for the Sept/Oct 2006 Maison Francaise, (one of a number of magazines belonging to a French interiors magazine group, Côté Maison, that I've recently been poring over....)
I don't understand how "blue" ever got to be a word about feeling down. These blues lift me up, up.