1 hour henna/cassia blend on 10% gray
I've had success rinsing henna/cassia mix out earlier, so I wanted to mention and post some pics.
I started using henna about a year ago and read in most posts to leave it 4+ hours. It came out so orange that I started experimenting with rinsing it earlier and have now settled on 1 hour (from when I finish applying which takes like 15-20m).
It comes out a pretty muted reddish brown, although its can be very red in certain lights. My bathroom mirror really brings it out so I got a photo of that too. This is the next day after dying, so the reddest it ever is then it fades down from that. These pics are all done at the same time, just in different lighting.
It completely covers the gray as long as I get good coverage and makes them pop like highlights. Besides that, it doesn't change my base color too much, so potentially a good option for those trying to blend grays and get an auburn wash, rather than going with a stronger orange/red.
This is a 50/50 henna/cassia blend - SaraHenna and generic cassia that I bought locally in Thailand. I used amla powder as the acid. I put a plastic bag on my head for an hour and done!