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black light
NOUN:
Invisible ultraviolet or infrared radiation.
Black
light causes fluorescent materials to emit visible
light and is used to take pictures in the dark.
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Who
invented the black light? |
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William
H. Byler is credited with inventing the black light
in 1935, and according to the University of Central
Missouri, Byler graduated there in 1927 with a major
in chemistry and physics.
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How Black
Light Works |
A black
light works by producing UVA light, or ultraviolet
light, that we cannot see. Ultraviolet light is above
the spectrum of visible light that our eyes can
process. When objects appear to glow under the light,
they are substances that are emitting light in
response to radiation. These "phosphors" are what make
normal things like teeth and white t-shirts glow in
the dark! See our black
light uses section.
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Black
Light Term |
The term
black light refers to a specific kind of
lamp---typically fluorescent---with a special
phosphorescent coating that emits UV radiation in the
UVA range.
Black lights are a kind of fluorescent light with a
special coating of phosphor, functioning as a
ubiquitous accessories in
college dorm rooms. Phosphors fluoresce (give
off light) when hit by radiation. The black glass in a
black light blocks normal visible light so the only
light hitting the phosphor coating is in the
ultraviolet spectrum. Ultraviolet light is
electromagnetic radiation just like visible light but
it is slightly more energetic. Undetectable by the
human eye, when UV light hits certain materials,
called phosphors, it causes them to glow. Phosphors
change the energy from the UV radiation to light we
can see (visible light). |
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Types Of
UV Light |
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Ultraviolet radiation (ultra meaning "beyond")
encompasses its own range of light rays, all of which
are undetectable by the naked eye (of humans, at any
rate).
UVA rays
are the longest-wavelength, lowest-energy kind of UV
radiation and the kind that is least harmful. It is
the UVB and UVC rays in sunlight that cause the most
damage, prolonged exposure to which can lead to
sunburn and skin cancer.
Black
light is a kind of UV light. Black lights emit
ultraviolet radiation (UV light). UV is radiation with
a wavelength just shorter than that of violet light,
which is the shortest wavelength of light in the
visible part of the electromagnetic spectrum. The
electromagnetic spectrum is the range of radiation
from benign radio waves to highly dangerous gamma
radiation.
Black light sources may be specially designed
fluorescent lamps, mercury vapor lamps, light-emitting
diodes, or incandescent lamps.
See our complete black
light page.
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UV-A
UV-A light
is often referred to colloquially as black light. This
is the most visible type of UV light, because it has
the longest wavelength. You can buy UV-A black light
bulbs at most stores. They release bluish-purple light
and are used in concerts and entertainment because
certain colors appear to glow beneath them. |
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UV-B
UV-B and
UV-C lights are more often referred to as UV lights
than black lights. UV-B lights are medium-wavelength
lights that release less visible light than UV-A
lights do. UV-B lights are used in forensics, because
certain human fluids are revealed under the lights.
Police can use these lights, for instance, to find
blood or fluids at a crime scene.
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UV-C
UV-C
lights have the shortest wavelength of all UV lights
and are effectively invisible to humans. UV-C lights
emit destructive radiation that kills germs. UV-C
lights, therefore, are mostly used for sterilization
and water purification purposes. |
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Black
Light Applications |
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UV light
also has other practical applications and artificial
sources. A fluorescent lamp without the phosphorescent
coating emits UV light in the UVC range--invisible and
highly energetic. This light can cause damage to the
skin with prolonged exposure but is commonly used as a
disinfectant.
UV light
is increasingly utilized in industrial and commercial
applications. UV light-emitting diodes, or LEDs, are
put to work in digital printing, where the light is
used to cure printed materials. LEDs are used in
traffic lights, indicator lights on airplanes and
large stadium displays, due to their low energy
consumption and small size.
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Black
Light Links Below |
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Uses For Black Light
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Different Types Of Black
Lights |
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