Light
is a form of electromagnetic energy that moves in measurable waves.
The human eye is capable of seeing only a small segment of the spectrum
known as visible light; shorter and longer wavelengths are not visible.
Therefore, shorter length cosmic rays, gamma rays, X-rays and UV light
and the longer length infrared and radio waves are all invisible to
humans. To be specific, UV energy radiates between 180 nanometer (nm)
to 400nm wavelengths in the narrow region between X-rays and just below
the violet end of the visible light spectrum.
More than 3,000 natural and man-made substances can transform invisible
radiated UV energy into longer, visible wavelengths that appear in a
variety of colors. These substances react to UV because they are composed
of easily excitable molecules. When UV light strikes one of these reactive
substances, this energy, in the form of photons, causes each molecule
to rotate violently. As the molecules slow down, they release this radiated
energy in longer, now visible wavelengths that appear to the human eye
as a glow in the color of the specific activated material. This phenomenon
called fluorescence, is instantaneous and ceases the instant the UV
light is removed. Fluorescence lets users detect otherwise invisible
traces that indicate various quality defects, diseases and contamination.
Ultraviolet
radiation has particular physical characteristics which affect such
phenomena as: Luminescence and Phosphorescence and can cause Fluorescence.
Short wave UV light is also widely used for sterilization.
Luminescence:
the emission of light produced by means other than combustion such as
the luminous glow of a watch dial.
Fluorescence:
the emission of light produced by certain substances when excited by
a UV energy source. This emission ceases when UV source is removed.
This is a characteristic, along with optical contrast and relief, that
enables users to see contaminants, etc. with RestAssured lights.
Phosphorescence:
the emission of light produced by certain substances when excited by
a UV energy source which continues after the energy source is removed.
Black Light:
lamp producing UV light in the range between 320-380 nm. This type of
long wave light is commonly referred to as "Black Light."
| Click
Here to see How to Perform
a UV Inspection |
| |
UV
LIGHT |
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|
| Short
Wave Length
Range: 180-280 nm |
UV-C
has germicidal power. Eye and skin
protection is required. |
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|
Medium
Wave Length
Range: 280-320 nm |
UV-B
is characterized by the ability to cause sunburn. Some eye and
skin protection is advisable. |
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|
| Long
Wave Length
Range: 320-380 nm |
UV-A
waves are commonly called Black Light
or Wood's Light. Long waves can pigment the
skin but do not cause sunburn. Eye protection
is not required, but recommended. |