This is normal skin from a person with a dark complexion. The amount of skin pigmentation varies among races and individuals. Melanin is made in melanosomes in melanocytes that are interspersed with basal cells of the epidermis. The number of melanocytes is relatively constant, so the degree of pigmentation and darkness of skin in different persons is determined by the number of melanosomes and the amount of melanin pigment produced. Melanocytes interdigitate their cytoplasm with adjacent epidermal cells and transfer melanin granules to them. Ultraviolet light exposure is the signal for melanosomes to use their tyrosinase enzyme to manufacture melanin.