Indigo

Almost always, an indigo treatment is done in conjunction with a henna treatment. Indigo alone can impart unpredictably bright and typically not desirable colours, such as green, purple or bright blue, depending on the base hair colour.
 
Most natural dye adherents do either a one-step mixture of henna and indigo or a two-step process wherein henna is applied first and then the darker colour is applied in a separate step.
 
You Can Colour Your Hair Naturally!
 
Reddish-brown can be achieved when using proportions of 70% henna and 30% organic indigo
brown tones can be achieved when using proportions of 50% organic indigo and 50% henna
dark chocolate brown tones can beachieved when using proportions of 70% indigo and 30% henna
black tones are achieved when you use henna first at 100%, and the second step of indigo at 100%