Hi I have dyed blonde on the top and my natural brown colour underneath. My roots have grown through on the top so I colouring them and they have come out a yellow colour I can't afford to go to the salon to have it fixed but I do have a little experience in hair dressing, so I was thinking of putting lowlights through the top to try and brake up the colour as I done with a friend of mine before and it turned out lovely but I can't remember what colour we used. I don't know what brown to put on it is if I use a ash colour I'm frightened it will turn out with a greeny tint to it. Shall I just use a dark brown? I have done my own hair for many years I also always do family and friends and never had any problem but this time I changed the normal brand of colour I use and I am now gutted!! Please help I'm going away the weekend and need to fix it by then!!

Color formulators assume that the haircoloring they're creating will be used on virgin, natural medium brown hair. When medium brown hair is treated with hydrogen peroxide, it turns reddish. That is the contributing pigment in the hair. The formulators add a lot of artificial green pigment to counteract that red (red + green = brown).

If you put a brown haircoloring on bleached blonde hair (either for a tintback or for lowlights), the red pigment that the fomulator expected to be present, is no longer there. You need to add back the red or the hair will have a greenish cast to it. You can select an auburn shade, or you can deliberately mix red with the shade you've picked. Of course, the darker the brown, the more red you need to add back in. That is where the art comes in.

Hope this helps.

Right, or basically pick a brown with the words warm, or golden in the color name.