Saturday, May 22, 2010
Weifa: Honey-yellow from Asia's honey-trees
The long hunt for the nature of Lo kao (described below) is in quite a contrast to the story of another dye of Chinese origin: the weifa. As weifa is produced of flower buds, it didn't take more than a good botanical observator (found in Fortune) to identify the nature of the dyeing material. Which turned out to be the 'honey tree', Sophora japonica. Some reports state that the buds are baked, but most reports mentions simple drying (but drying in hot climates may mean something else than in temperate regions..)
First imported after the mission of Isidore Hedde for the French government (1843-46), they were compared to anise seeds, but were already soon discovered by Henon (1847) to be flower buds. Experiments by Lyon silk dyer Guinon showed that the bright yellow dye components turn brown when the flower develops, so early harvesting seems necessary.
It is said that the famous imperial yellow of the emperor's robes was dyed this way, but I have not yet found analytical proof for this.