When the skin is exposed to
Ultraviolet (UV) rays, a natural process begins to take place.
There are special cells in your epidermis, which is the outermost
layer of your skin, called melanocytes. When exposed to the
UVB (shorter) ray, these melanocytes produce melanin, which
is the pigment that is then absorbed by the surrounding skin
cells. When melanin is exposed the UVA (longer) ray, the melanin
then oxidizes, or darkens, creating a "tan".