i have naturally dark brown hair, but i keep it black & blonde.
they used to sell this jet black powdered hair colour at Hot Topic that was called RAW. you just mix the powder with water & it turns to this gel-like consistency and you apply it like hair colour. no harsh chemicals, smelled awesome, and most importantly, DID NOT crispy my hair! it last forever, too! it didn't wash out in to my blonde, either. i would only have to color my hair every couple months, and that was just to touch up the roots, because that stuff didn't fade in the least! it was cheap, too, so that made it the perfect hair color. i was seriously in LOVE with that stuff!
sadly, the discontinued it & now their RAW 'jet black' comes premixed in a bottle. i used it ONCE. it smells like grapes & turned my blonde chunks blue. i'm totally ok with turning my blonde bits pink every now & again, but i do that on purpose!
now, since they went and f-ed with a good thing, i use Feria, which is ok. it doesn't last near as long as the other did & if i use Starry Night, it turns my blonde blue-ish. i don't remember what the other black colour is called, but it isn't as dark & is more of a brown-ish. Starry Night is a better black i think, but it has that unfortunate blue effect.
ramble ramble ramble.