The darker the hair, the more warm and subtle your end result will be. You want it to be clean and not coated with any leave-in products, which can block the absorption of the conditioner. The easy way is to do it in the shower directly after shampooing – oVertone works on wet or dry hair. If you use it on dry hair, you’ll see a little extra saturation.
You want to ensure your hair is completely soaked with conditioner for even coverage! No dry spots here.
After about 15 minutes, you won’t see any extra color saturation, but the emollients in the conditioner will continue to soften your hair. So unless you’re looking for extra conditioning, there’s no need to leave it on as long as you’d leave on a dye.
See the whole tutorial on Youtube below: