Coloring bleached hair often produces the best results and is a common practice according to Clairol. Bleached hair removes the pigment from the hair, leaving the hair ready to fully absorb a new color.
The best way to get a bright, vibrant hair color is to bleach the hair first to remove the original color, especially if the new color is lighter than the natural color. After bleaching, the hair is ready for the new color application once it is dry unless the hair has a lot of damage. In those cases, users should apply a deep conditioning treatment and wait at least 48 hours after bleaching before applying the new color. After coloring, wait another 48 hours before washing, although additional conditioning treatments are good during this time.