I am so glad to see this thread! So many people do not realize that black henna is not a naturally occurring 'type' of henna. As already stated by someone, henna plants are green. The color they leave on skin is orange to brown depending on your body chemistry.
Some cultures mix the henna with dark brewed tea or even coffee to make the color darker. In some cultures, the darker the color of a bride's henna , the more love she will receive from her mother in law, lol.
I have been using henna both for my hair and body since I was a child. I can actually get good grade FRESH henna to go black on my hands by repeated(at least twice) application and heat. I usually use a hair dryer in winter if it is cold.
Henna is great, but so many people do dangerous things with it. I cannot believe people think its ok to add hair dye to it
