How Do Tanning Beds Work?

The Pioneering Technology

German inventor Friedrich Wolff introduced the tanning bed to the market in the late 1970s after developing a blend of phosphors that produced ultraviolet rays similar to those of the sun. He developed fluorescent light bulbs that contained phosphor blends of two different kinds; one produced UVA rays and the other produced UVB rays. Both of these types of ultraviolet rays are emitted by the sun, and they both work together to produce dark or golden tans through regular exposure to sunlight.

The Design of the Beds

Tanning beds are so called because they are similar to beds in shape and size and because users lie down on them during use. Most are more similar to chests or caskets because they feature lids that users pull down. Both the bottom half and the top lid of a tanning bed are lined with fluorescent UVA light bulbs and a much smaller number of UVB bulbs. These bulbs are powered by electronic ballasts which run on regular electricity and which control the wattage and UV production of the bulbs. The user is separated from the bulbs on both halves of the bed by large panels of clear acrylics. To make the beds comfortable, these panels usually have a concave shape and the bulbs are arranged in a concave pattern beneath them.

The Effects on the Skin

To tan in a tanning bed, a user lies down on the bottom acrylic panel and lowers the lid. When the bed is activated, all of the UVA and UVB bulbs turn on. The UVB bulbs, which are fewer in number than the UVA bulbs, emit ultraviolet-B rays. These rays stimulate the production of melanin, a brown skin pigment. The reason for this is that UVB rays present a harmful radiation risk to the skin, and darker skin slows the absorption of these rays. The release of melanin is therefore a natural part of the body's defense system. Overexposure to these rays is what causes sunburn.

UVA bulbs are more plentiful in tanning beds because UVA rays are more plentiful on earth. The sun produces UVA and UVB rays at a ratio of about 20:1. Their role in tanning bed design is to transform the color of the melanin produced by the UVB rays into a more aesthetically pleasing golden brown color. The UVA rays do this by penetrating the skin and oxidizing the melanin, which softens and smooths the color.