EFBE-SCHOTT OKB 920 D Manual página 10

SKIN TANNING INTRODUCTION
The sun
The sun is the source of life on earth. As we can see from the rotation of the seasons and
from our personal holiday experiences, light and warmth have a huge impact on our health
and physical well-being. A bronzed skin is generally associated with a healthy and
attractive appearance and, thus, enhances a person's self-confidence and well-being. At
the same time, a suntan serves the biological purpose of protecting our skin from sunburn,
particularly before going on a summer holiday.
The tanning
The tanning process is stimulated by a certain part of the light spectrum, regardless of
whether the light is naturally produced by the sun or artificially produced.
Sunlight contains both a visible spectrum, which can be detected as light by the human
eye, and invisible rays, such as those we feel as heat or that can lead to reddening of the
skin or even sunburn. Rays that tan our skin belong to the spectrum of invisible ultraviolet
(UV) radiation. It consists of three components: UVA, UVB and UVC radiation.
A perfect tan requires a preferably intense amount of UVA radiation, a very low amount of
UVB and no UVC radiation at all.
UVC rays are blocked by the earth's atmosphere, while UVB and UVA rays do pass and can
tan our skin. However, the rather high amount of UVB radiation emitted by the sun might
quickly lead to excessive irritation, reddening and, hence, to sunburn in people with pale
skin.
UVA tanning devices
UVA tanning devices by efbe-Schott feature a more favourable composition of UV
radiation compared to natural sunlight. The intensity of UVA radiation is much higher than
in natural sunlight, while at the same time, the harmful UVB radiation has been reduced to
a fraction of the amount that is present in natural sunlight. In comparison to natural sunlight,
the tanning process is usually accelerated while there is normally no risk of sunburn. The
tanning colour that can be obtained is similar to a natural suntan.
However, the skin's reaction to sun rays varies from one individual to another.
Skin types and exposure times
Each of us knows their skin's individual tanning behaviour when exposed to direct sunlight.
Thus, a similar reaction of our skin may be expected from exposure to artificial UV light.
People who can tolerate the sun very well tend to tan more quickly, while those who are
unable to tan in the sun have only little chance of success when using UVA tanning devices.
Classification of skin types according to the reaction of the skin that has not been pre-
irradiated to natural sunlight :
Skin type
Always get sunburned quickly, hardly or no tan, even after repeated
I
irradiations (Celtic type)
Almost always sunburn, moderate tan after repeated exposures (fair-
II
skinned type)
Moderately often sunburn, progressive tanning after repeated irradiations
III
(dark-skinned type)
IV
Rarely sunburn, rapid onset and clear tan (Mediterranean type)
Skin reaction and ethnicity
10