Skin color is determined by a pigment melanin made by specialized cells in the skin melanocytes. The amount and type of melanin determines a person's skin color. Melanin gives color to the skin, hair, and iris of the eyes. Levels of melanin depend on race and amount of sunlight exposure. Sun exposure increases melanin production to protect the skin against harmful UV ultraviolet rays.
How to Change Skin Color From White to Black
Real life story: My black skin turned white - BT
Cold temperatures, low humidity, and strong, harsh winds deplete the skin of its natural lipid layer, which would normally help keep the skin from drying out. Skin of color in particular, can become very flaky, dry, and "ashy" in the winter. Differences in the stratum corneum barrier in skin of color may contribute to the propensity toward ashiness. The barrier function of the skin depends on the structure of the corneocytes, lipid content, and transepidermal water loss. Compared with skin in white people, black skin has more corneocyte layers and a more compact stratum corneum with greater intercellular cohesiveness. The epidermal barrier in darker skin has been shown to be stronger when exposed to mechanical or chemical challenge.
Black patches of skin
It is well known that melanin in brown skin provides protection from the ravages of aging due to ultraviolet light UVL. In fact, the melanin in African American skin provides a natural sun protection factor SPF of about 13. This natural protection from the sun means less damage to the skin and fewer signs of aging. Therefore, melanin in the skin of African American women accounts for the fact that they often appear younger than Caucasian women of the same age.