Logwood is isolated from the heartwood of Haematoxylem capechianum. Logwood produces a rich purple or black with iron.
Use the wood chips at 10-15% weight of fiber. Pour boiling water over the chips and leave overnight to extract the dye. The first water bath will produce the strongest colors, but the chips can be used again for lighter colors. Simmer mordanted fibers at 170-180°F (77-83°C) for 1 hour.