* Eumelanin: Produces brown and black pigments. More eumelanin results in darker hair.
* Pheomelanin: Produces red and yellow pigments. More pheomelanin results in red or blonde hair.
The combination of these two pigments in varying amounts creates the wide range of hair colors we see.
So, the color of hair can be:
* Black
* Brown (ranging from dark brown to light brown)
* Blonde (ranging from platinum blonde to strawberry blonde)
* Red (ranging from bright red to auburn)
* Gray/White (lack of melanin)
* Other mixed colors
Therefore, the color of hair can be one of the colors listed above, or mixed of them.