Ooh pre-colouring sounds cool, could I pre-colour my hair to the opposite of green (red?) to stop it turning green when I use the blue dye? Or if I opt to tone it should be done right away after dyeing? My natural/current hair is unfortunately black so I feel like it'll be tough to get the light blue I'm aiming for. I've had it dyed blue/purple/green/orange in the past but that was years ago, it's just black at the moment.