In ancient times, from opulent Egypt to stark West Africa, fabric has been dyed a mysterious, beautiful blue. This indigo, or "gold blue," is a sign of prestige and a symbol of the link between heaven and earth. Through a careful process, indigo can produce a vast palette of blue hues; traditional dyers would ask their customers' color preferences, from the palest sky to the deepest midnight. Dye vats alone take a full week to prepare and require daily stirring. The un-dyed cloth is pinched, sewn, and tied according to precise patterns. Once dye is applied to the material, the ties are removed, revealing patterns of lines, shells, dots, or tracery.