Hair coloring, or hair dyeing, is the practice of changing the hair color. The main reasons for this are cosmetic: to cover gray or white hair, to change to a color regarded as more fashionable or desirable, to restore the original hair color after it has been discolored by hairdressing processes or sun bleaching.
Hair coloring can be done professionally by a hairdresser or independently at home. Today, hair coloring is very popular, with over 75% of American women dyeing their hair. At home coloring in the United States reached $1.9 billion in 2011 and is expected to raise to $2.2 billion by 2016.