Okay, here's how I got the colour.  I have naturally medium brown (wig shade 8, actually, don't ask why I know) that tints reddish in the sunlight.  The colour here is from about seven months of hennaing my hair every month and a half or so.  I use inexpensive henna from ebay that actually gives a pretty good body stain, but I'm not sure where it's from, and lemon juice. I "terp" my henna for hair with lavender or clove essential oils.

It takes a lot of henna to do my hair (it's to my hips).  I keep it all in a big, giant plastic freezer bag in the freezer, and scoop it out as needed.  It take 4 heaping ice-cream scoops to get enough henna.  I mix that with warm lemon juice (room temperature) and whichever oil I'm using and cover it with plastic wrap.  Once there's dye release I slather it on, put a plastic disposable shower cap over that, and do homework or something.  Once it's been at least two hours and I'm starting to go crazy from having stuff on my head, I go and wash it out.  I find that once you've gotten the largest bits out, putting conditioner of some sort helps.  I shampoo every time I shower, and use a tea-tree oil conditioner to help keep the colour bright.

Alison