My apologies as I meant to say its normally brown in colour not black
said it the other way round
(somehow)
Black henna", sometimes referred to as "kali mehndi" or "piko" is henna that that has been adulterated with the transdermal toxin, p-paraphenylenediamine (PPD for short) mainly used as a hair dye. In some cases this so-called henna doesn't even contain any henna at all.
Natural henna products are dark brown, almost looking like they are black, Jagua is a tropical fruit with a natural blue dye and when mixed with henna, the stains are extremely dark and long-lasting, Additionally, skin that is more alkaline tends to stain better, as well as the skin of people that are younger, healthier and more active.
Traditional henna? Henna is a shade of reddish brown. Depending on where you get the tattoo and how well it absorbs into your skin, the colour can range from a light brown to an almost black-brown.
Black henna is adulterated products containing harsh chemicals that are not meant for any skin types and have been associated with cancers and other medical conditions.
As someone who has grown up in a Muslim country and has several relatives there, Black henna is just simply unknown of and is even banned in several countries.
Ds's were both in Turkey for the summer holidays last year and learnt about Mehndi traditions, ds1 was the pretend groom, due to this we had to ensure henna was safe.