Tanning in the Shade
Can a person get a tan while wearing a
t-shirt or sitting
in the shade? In other words, does the sun have an effect
on the skin, while either of these two conditions exist?
Thankyou all for your help!!
It all depends on the amount of exposure to UV. If you are getting direct
or indirect UV it will stimulate a response by melanocytes to produce more
One does not get a tan if he or she in the shade where the sunlight is
blocked, for example, by the roof of a house. In order to get a tan,
one needs to be exposed to direct sunlight. What toasts the body (also
called tanning) is the ultraviolet (UV) part of sunlight radiation. This
is not the visible part of sun's radiation. One can get a tan with a
cloud cover overhead because UV radiation can get through some obstacles
(clouds in this case). Clothing generally blocks UV radiation, that is
why one wears a hat under the sun to protect head and face against
radiation. I am not sure but guess that it may be possible to design
clothing that let at least some UV get through.
Having received many sunburns, I feel qualified to answer your questions.
Nowadays "they" try to tell us that clothing does not protect us from all
the sun's damaging rays, and that it is thus necessary to wear sunscreen
even under clothing. Well, I have been sunburned even through SPF 30
sunscreen many times, but never, not once have I been sunburned through
clothing. So a T-shirt probably provides adequate sun protection, unless it
is really threadbare. Of course, a T-shirt will do nothing for exposed
It IS quite possible to get a sunburn while sitting in the shade or on a
cloudy day. Like blue light, ultraviolet scatters off the atmosphere, and
can reach you even if you are in the shade. Basically, if you can see the
blue sky, UV can reach you.
The actual protection you get from a sunscreen depends on the concentration
of its chemical that absorbs UV, how effectively it absorbs UV, how thick a
layer of the stuff you have on your skin, and how easily it washes, wears,
or sweats off. The sunscreens with higher SPF factors either have higher
concentrations of UV-absorbing chemicals, or they have more effective
UV-absorbers. There is no theoretical maximum value for SPF of a sunscreen.
Richard E. Barrans Jr., Ph.D.
PG Research Foundation, Darien, Illinois
I can add on thing to the above; UV rays can reflect off of water and other reflective surfaces
and as a kid, I got a terrific sunburn once and I was not exposed to direct sunlight for most of the
outting. I have light skin and I'm a redhead. This topic has always been a problem for me.
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Update: June 2012