My hair is naturally blonde, my hairdresser dyes it permanent black yet it always looks dark brown, help?

I was just wondering if anyone knew why or whatever. Thanks ;DMy hair is naturally blonde, my hairdresser dyes it permanent black yet it always looks dark brown, help?
the only way I can think of is to dye it, wash out the dye, and then repeat the entire process.....you may have to go back a couple of times in a week to get it there!My hair is naturally blonde, my hairdresser dyes it permanent black yet it always looks dark brown, help?
uhm usualli u have to dye it another color before you do the black especialli if it is blonde,cause its gonna end up being brown lol