Deep in the epidermis, melanocytes make a pigment called melanin. They hand it to nearby skin cells. Melanin soaks up UV rays. It sits over each cell's nucleus like a tiny umbrella and protects the DNA. Turn up the sun and watch.
Mild sun
Melanin & UVthe built-in sunscreen
Set the UV exposure
Skin color comes from three pigments. They are melanin (brown-black), carotene (yellow-orange), and hemoglobin (the red of blood showing through). Here is the tradeoff. Melanin blocks harmful UV. But your skin also needs a little UV to make vitamin D.
๐ท Reference image
A real labeled picture to compare with the interactive above.
Skin Color & Melanin โ OpenStax College, CC BY 3.0 (via Wikimedia Commons)