UV lighting

[T L]

In "UV lighting for dummies" terminology, what is the difference between using a shortwave UV light vs other kinds? What other kinds are there, and what are the differences?

 

[stone-cold11]

Short wavelength is more energetic, less visible spectrum, long wavelength is the UV spectrum closer to the violet of the visible spectrum, more visible.

 

[kenny]

I thought it had to do with how long you kept the light on.

 

[FB.]

Light comes in all colours of the rainbow - starting at red, moving through orange, yellow, green, blue and violet.

Wavelength is the frequency of the light transmission. Ultra violet has a short wavelength just a couple of hundred nanometres (say 200). Visible light is in the mid-100's nanometres (say 500). Infra red has a long wavelength close to 1000nm (say 800).
It's a continual scale, so it's possible to have infra red in many frequencies. I have some nightvision devices. One uses "short-wave" infrared that's just off the visible range - about 700nm. Another uses "long wave" infrared that is a long way out of the visual range - about 900nm.

If someone said "long wave UV", I'd assume UV that was only just off the visible spectrum of light. If they said "short wave UV", I'd assume that it was well out of our visible spectrum.

 

[T L]

Okay, so what''s the difference when using a true SW UV light vs one of those cheapie LED UV lights?

 

[stone-cold11]

Depends on what you are using it for.

Certain excitation occurs only for certain wavelengths.

 

[T L]

I just want to see the color of the fluorescence. What is excitation, something to do with subatomic particles?

 

[FB.]

If you want to see the colour of the fluorescence, take it outside in sunshine.
If you use a UV torch, the appearance of the fluor will look slightly different than in sunshine.

Excitation is to do with the subatomic particles. The atoms in a fluor diamond change the wavelength of UV light and it then becomes lilac/purple/blue light at the extreme end of the range of colour that our eyes can see, whereas the UV light might originally have been out of your visual range.

 

[T L]

What is a UV "torch?"

 

[stone-cold11]

When UV is absorbed by the atoms, it excites the electrons of the atoms to a higher energy level, when the electrons jumps back to lower energy level, blue light is emitted, thus fluorescence.

http://en.wikipedia.org/wiki/Fluorescence

 

[FB.]

Date: 11/3/2009 2:29:23 PM
Author: tourmaline_lover
What is a UV ''torch?''

Type "ultraviolet torch" into an internet search engine and you''ll get lots of results.

 

[stone-cold11]

Date: 11/3/2009 2:29:23 PM
Author: tourmaline_lover
What is a UV ''torch?''

Essentially a torch/flashlight with a UV bulb.

 

[LD]

TL you may find this article interesting. It shows how the GIA grade fluor and the methods used.

http://lgdl.gia.edu/pdfs/W97_fluoresce.pdf