hi everyone just thought id add a tip
this is great and hasnt damaged my hair at all, i'd had my hair dyed black and blue/purple for 6 years and fancied dying my hair for a change...to a reddish brown,close to my natural colour, i took some vitamin c tablets and mixed it with some conditioner to make a paste then i left it on my damp hair for just over half an hour i think, i done this twice over a few days and it took almost all the purple out and faded the black (been permanent black for 6 years) to a mid brown,woohoo!! as a result it was easier to bleach lighter
hope this helps! its good if you have bleached your hair for a bright colour like special effects/manic panic etc and want to change to a completely different colour.