Dried safflower petals (Carthamus tinctorius) — one of the oldest dual-colour dye sources. The petals contain two pigments: a water-soluble yellow (safflor yellow, easily washed out) and an alkaline-soluble red (carthamin, the prized pigment). By first washing out the yellow in cold water, then extracting the red with alkaline solution, a single batch of petals yields both colours. Used in Egyptian tomb wrappings (c. 3500 BCE), Japanese beni cosmetics, and Chinese silk dyeing.