When coloring hair that is more than 25 percent gray, choose a permanent hair color with neutral, red or gold undertones, and leave it on for the entire length of time defined in the instructions. Semi- or demi- permanent hair colors, and hair color with ash undertones, aren't as effective for coloring grays. Gray hair tends to be resistant to hair color and often needs more time to process than other hair types.
Gray, silver or white hair is hair that has lost its natural pigment. Semi- or demi-permanent hair color may work for those with less that 25 percent gray hair, but permanent color is a better choice for covering more gray for longer periods of time. When coloring gray hair at home, begin with the grayest sections of hair first to give them the most processing time.
Choose a hair color that is the same shade or lighter than the hair's natural pigmented color. Dark colors tend to wash out old skin. Use gray hair to create natural-looking highlights by choosing a shade lighter than the remaining pigmented hair.
Hair color contains peroxide and damages hair over time. To avoid excess damage, color only the roots between all-over colorings, avoid heat styling whenever possible, and use shampoo and conditioner formulated for color-treated hair.