ABSTRACT
Hair coloring is a technique used by both men and women for altering the natural hair color or camouflaging the presence of gray hair (Figure 4.1).1 The hair color can be changed until the next shampooing, for 8-12 shampooings, or permanently.2 It can be dyed darker than the original hair color or lightened. This invention has added a whole new dimension to hair cosmetics and created a huge at-home hair dye and salon industry.
