My hair is too dark to just dye. I know this. My last blue-hair attempt ended up black because of this.
Forgot how long it takes to bleach my hair, though (first reminder: ‘why didn’t i bleach it before i dyed it last time again?’) Fine hair + dense hair + dark hair = it takes about two hours just to get the bleach worked into all my hair and another hour to really strip the colour out.
Which i’m not quite patient enough for, so now i’m mostly a medium blonde. Whatever. It’s light enough for the blue to look blue when i finish the dye job next week :D