Thanks so much ktani! I have read through all the Q&A, but, as you say, it's a lot to take in. I was probably clicking on every link, then trying to retain all the information!

I'm attempting to lighten henna'd hair incidentally. The top few inches are less red, because I transitioned to a henna/cassia mix (left on for less than two hours) and the bottom is just henna (left on for three or four hours)
It actually looks ok (although if I hold the ends to my scalp it's a totally different color!) but I'd like to lighten the whole lot if I can.