a.applying to non-dyed hairIn order to distribute the mixture very evenly,use a comb to separate hair into four distinct areas and carefully apply the mixture to the roots using the applicator nozzle before going on to cover the length of the hair to the tips.use up all the dye and gently message in to make sure all hair is covered then leave on for 30 minutes.for deeper colour,or to cover more resistant grey hair,increase waiting time to 40 minutes.B.applying to dyed hairWhen touching up:apply to roots first and leave on for 20 minutes,then cover the remaining length of hair and leave on for 10 minutes more.