MODEL RELEASED. Sunscreen application. Woman having sunscreen rubbed onto her back. When sunbathing, sunscreens should be applied to protect the skin from the dangerous effects of ultraviolet radiation present in the sunlight. Repeated overexposure to the sun causes premature ageing and may also increase the risk of skin cancer. Dark skins are less susceptible to skin cancer than fair skins but should still be protected. Most sunscreens protect the skin by absorbing the ultraviolet radiation. The typical compound used is para-aminobenzoic acid (PABA). Other sunscreens use compounds such as titanium dioxide and work by reflecting the Sun's rays.