To start, my hair was dyed Marilyn Monroe blonde with my brown roots showing. In the picture, which I took right after the second time, you can see it turned out light red in natural lighting, with black at the tips. After a few days it darkened, but only a little, so it pretty much looks like in the picture.

Here is how I did my hair:

First I mixed 1 cup mildly acidic liquid with about 75 grams of Ancient Sunrise henna. I left it to sit overnight.

My boyfriend applied about half of it to my short hair, with surprisingly little mess. I covered it in plastic and put a hair towel around my head. I left it on for around six hours, I was too impatient to leave it on for longer and we wanted to go out to a movie. Unfortunately it didn't quite get as dark as I would have liked it, so the next day I used the rest of the mix that I had put in the freezer and left it on my hair for another six hours. After it was red enough to my liking, I mixed up some indigo with water and used it to dye the tips and the back of my hair. I left it on for about an hour.

This was very messy and dripped since I couldn't really wrap it up or it would ruin the design. It also dried out a little and didn't dye as well, (it was green at first), so I also had to do the indigo twice. In retrospect, it probably would have been easier if I had used tin foil to seal the ends up and there wouldn't be blue spots on the bathroom floor! But after a few mistakes, it finally came out how I wanted it.

Notes and References
Henna: https://www.mehandi.com/Mehandi-com-Ancient-Sunrise-Henna-for-Hair-s/121.htm
Don’t have fruit juice on hand? Keep some fruit acid powders in your cupboard.
Mildly acidic liquid: https://www.mehandi.com/Fruit-Acid-for-henna-dye-release-s/299.htm
More info on mildly acidic mixes: https://www.tapdancinglizard.com/henna-and-acidic-mixes/
Henna time and temperature: https://www.tapdancinglizard.com/mixing-and-testing-your-henna-mix pp. 10-13

Video How-To
Going red with henna: https://vimeo.com/manage/videos/739464950