It all depends on what colour brand you use. All brands are made of different chemicals that make up the black. If you use permanent colour, it will penetrate inside of the hair cuticle and will most likely fade to a reddish black (the undertone of black is a red). If it is a midway (not permanent) colour, it will most likely fade to a muddy brown. It will be very hard to get your hair back to it's original colour after colouring it black. It won't fade to a grey.
i agree with renee, it ill not fade to grey dont worry about that. it might also fade to blue because that is another undertone of black as well as red, itall depemds on the brand you get, like when you look at a older lady and she has black hair and in the light it shimmers a dark dark blue, well blue is the undertone in that color, just giving an examle. and it would be very very very hard to get black out of your hair color, i wouldnt suggest dying it
So my hair is like a cool blonde, or like a silvery blonde. What color will black fade to? Will it fade to grey or brown?
most likely grey