The term tanning refers to darkening of the skin especially the darkening of the fair skin. The most natural way of tanning is sun; tanning through sun is caused by UV rays present in the rays of sun. The darkening of the skin can be removed by taking some measures. The excess tanning of the skin can cause sun burn which in turn is not good for health. When the skin is exposed to the sun then the cell of the skin releases more pigment melanin which makes the skin look dark. Melanocytes are the cell which produces the melanin. The melanin protects the skin from excess absorption of sun radiation. The skin type of every person is different and their genes are also different. Depending on this fact the skin of some people become tan very soon and other resist tanning.

Ultra violet rays

The ultra violet rays are divided in two categories namely UVA rays and UVB rays. The wavelength of UVA rays is 315 to 400 nm and the wavelength of UVB rays is 280 to315 nm. The UVB rays are more damaging to the skin as compared to UVA rays. The UVB rays have higher energy and more carcinogenic as compared to UVA rays. Excessive exposure to the ultra violet rays is damaging for the skin and health.

UVA rays and UVB rays

The UVA rays cause the release of preexisting melanin from the skin. The UVA rays combine with the oxygen which creates the tan on the skin. These rays are less responsible for cancer as compared to UVB rays. Sunscreen lotion cannot block the UVA rays but skin can be protected by clothing. The UVA rays are present in the atmosphere uniformly throughout the day and in all the seasons of the year. The UVB rays are responsible for creation of new melanin in the skin. It is more responsible for the skin cancer. Excessive exposure to UVB rays causes aging of the skin. The UVB rays are responsible for simulation of vitamin D, which is good for health. It is possible to block UVB rays efficiently by almost all the sunscreen lotions.