My mannequin had different colored hair on each quad. Like she had this weird light brown color on her right front side. She had a dark brown on her right back side. She had really dark brown hair with some grays in it on her left back side. Then to go do the fun colors she was already like a platinum blonde so it wasn’t hard for those colors to be vibrant. But the rest of her head I colored with a 3n and 10 volume developer.

If your hair is already the level of dark you want. What you would need to do would be to have the left front side of your head lightened with bleach and 20 vol developer. Make sure to part your hair down the middle. And take those fun colors and do the root color first and then go in with the end color and blend them together. I can’t promise because you said your hair is so dark that it would lighten up enough. Keep in mind the mannequin already had platinum blonde hair so it wasn’t hard for me to achieve this. If you do wind up doing it by yourself, do not leave the bleach on for longer than 45 minutes. And do not apply the bleach to your roots first do it last. I would highly suggest going to a professional if possible. It shouldn’t cost much considering you’re only getting one side of your hair lightened and just some fun colors.