there are varrying methods to dye black. most often these include combinations of tannins, brown dyes and minerals. the most colorfast of these blacks are those fixed with copper and iron, but very strong mineral preparations can damage the fibres, shortenning their lifespan. on a very dark indigo blue cloth, overdyeing with oak, catechu or walnut gives a beautiful deep black. through layering pigments, dyeing red, yellow and blue also produces black.