The resulting color of a henna mix depends on the ratios of plant dye powders, and the acid. Henna acts as the base of almost all mixes, indigo darkens, and cassia dilutes. Your choice of acid will brighten, deepen, or cool the henna color.
Nearly any natural hair color is achievable with the correct mixture of plant dyes.
The quick and dirty facts about henna for hair are the following:
Henna by itself stains keratin a range of shades between copper and dark auburn.
Indigo darkens and browns these shades, and cassia lightens these shades, adding golden tones.
Equal parts henna and indigo will result in a medium brunette on most. More indigo will result in darker and darker shades of brunette.
Equal parts of henna and cassia results in bright, fiery tones of copper and orange. More cassia will result in lighter and brighter tones of strawberry blonde.
All three together will result in more neutral shades of deeper blondes and golden brunettes.
Henna first, then indigo second in a two-step process results in a shiny jet black color.
None of these powders or mixes will turn darker hair a lighter color.
The amount of product you need will depend on the length and thickness of your hair. If you have very short hair, you will want to adjust your measurements to save product. If you have very long hair, you will have to increase the amount of product you are using. The representatives at are there to help you if you need it.