Zeba Indigo Powder if mixed with henna, it can make your hair light brown, medium brown or dark brown. Adding henna to indigo warms the color to reddish rather than blueish undertones. Indigo leaf powder is a completely pure form of indigo. This is safe to use as hair color dye.Indigo powder is used to deepen the intensity of our herbal hair colors naturally. It oxidizes when exposed to air and water so when this is mixed with warm water it becomes ready for use.