Sunburnt skin. Coloured electron micrograph (SEM) of epidermal skin cells after sunburn. These stratified epithelial cells have been destroyed by ultraviolet (UV) light in the sun's ray and are sloughing off. UV radiation also damages the tiny blood vessels beneath the epidermis. Sunburn is most common in fair-skinned people, whose skin lacks the protective pigment melanin. Repeated exposure prematurely ages the skin and increases the risk of skin cancer. Calamine lotion and painkillers help to soothe sunburnt skin. Magnification: x4000 when printed at 10 centimetres wide.