Colour in Cosmetics, with Special Emphasis on Hair Coloration

Cosmetics may be broadly defined as materials that are used to enhance the appearance or appeal of the human body. Cosmetics may also be described by the physical composition of the product; for example, they may be formulated as liquids, lotions, creams or gels (emulsions or dispersions), sticks (lipsticks), powders (loose or compressed form), or as aerosol sprays. Colour is of prime importance in the subset of cosmetics generally referred to as make-up, coloured products applied to the human body, mainly to the facial area, to enhance the appearance and attractiveness of the (mostly female) users. This chapter deals with the principals involved in the colorants used in these decorative cosmetic products, followed by a more detailed discussion of the chemistry which has been developed specifically for use in the coloration of human hair.