How do henna and indigo work?

[Jyoti]

The henna and indigo we sell are sourced purely from crushed leaves of henna and indigo plants; they are not extracts, they have not undergone any treatment process, and they do not contain man made chemicals or additives. The way they work is different from other hair dyes, they do not disturb the natural chemical make up of the hair. The colour coats each individual hair shaft without infiltrating it. On grey hair, it behaves differently - henna penetrates the inner hair shaft of grey hair and dyes it red orange, but using indigo turns it a deep brown to black, depending on how long you leave it on for. In my experience, if you have dark hair, henna will add deep reddish tones and make your hair look like it has natural red lowlights; any odd greys will look like reddish highlights. It will enhance your own natural hair colour and shimmer in the light therefore the end result will always be unique to you. On lighter hair colours like blonde/ash, the results will be more dramatic. It’ll be red/red orange. But if you don’t want red hair colour, then you can tone it down to a brown hair colour or a black hair colour with indigo. I cover my entire head because I have a lot of gray but it can be used on strands with foil to keep it in place for highlights( or is it lowlights?). Experimentation is the key.

[HennaHelen]

I'm quite adventurous with my hair so I enjoy the fact that when I dye with henna I'm never 100% sure what shade my hair is going to become.
I know it will be in good condition and I know that it will have reddish/orangey tones but it's never the exact same shade as the last time.