Blend equal parts bleach or powder lightener and 20-volume color developer in the color bowl until it is a creamy consistency. You can you use the color brush to mix and blend the color.
Apply the lightening mixture to the hair from where the black dye starts at the scalp through to the ends. Do not place the lightener on the regrowth or root area where the black dye is not present. Apply lightener to half-inch by 2-inch sections at a time. Brush the lightener onto each section of hair, and work it into the hair with your fingertips. Continue until all of the black hair is saturated with the lightener.
Set a timer for 10 minutes. Clean away a small bit of the lightener with a dampened corner of a towel to check the color underneath. If your ultimate goal is dark brown or reddish brown, lighten the hair to a reddish tone. For medium brown, lighten to orange. For light brown, lighten to yellow. For blond, lighten to pale yellow. Reapply lightener to the test portion of hair and wait another 10 minutes if the color is not quite right.
Rinse the hair thoroughly. Shampoo, condition and towel dry. Dry the hair completely with a blow dryer. Clean the color bowl and color brush to get ready for the color application.
Pour equal parts hair color and 10-volume color developer in the color bowl. Mix thoroughly. Apply color root to tip using small sections just like you did for the hair lightener.
Set the timer for 20 minutes. Rinse, shampoo and condition. Towel dry, style, and check out your new color.