According to The Journal of Nutrition, melanin and carotene are two of three pigments that determine skin color. The third pigment is hemoglobin. All three pigments are made in the epidermal layer of the skin.
According to the American Academy of Dermatology, melanin is the pigment most responsible for determining skin color. People produce differing levels of melanin. More melanin production means darker brown or black skin, while little melanin production causes very white skin.
Carotene is the least common skin pigment and causes yellowing of the skin. Naturally Healthy Skin notes that yellow skin is an indicator of too much carotene caused by over-consumption of foods containing beta-carotene.
The Journal of Nutrition states that hemoglobin works in conjunction with melanin and carotene to produce skin color. Hemoglobin is a molecule that carries oxygen throughout the body. This produces a pinkish tinge to skin. Varying amounts of these three pigments produce each person's unique skin tone.