Fist, the visible light spectrum is from about 400 NM (neat ultraviolet) to about 700 NM (near infrared). Although part of the light spectrum, you cannot see true ultraviolet beam (< 300 MN).  You can see the beams reaction to that frequency in certain materials. You also cannot see an infrared beam (>800 NM). You can see that these are on sometimes due to the reaction of surrounding materials to this light. http://en.wikipedia.org/wiki/Spectrum_of_light A WORD OF CAUTION TO THOSE IDIOTS TRYING OT LOOK INTO THESE BEAMS AS SOME CAN SERIOUSLY DAMAGE YOUR EYES!!

LED's can put out both visible and non-visible light, but not from the same LED. They can also be made into non-visible lasers. However, LEDs inherently have a very NARROW in it’s spectrum (allowing only few nanometers). A blue, has zero infrared, a red has zero ultraviolet. It CAN be designed to put out light in the NON-VISIBLE spectrum at both end, both ultraviolet and infrared. As for WHITE LED's they are a broader spectrum including much of the primary colors spectrum, not much outside of that. http://en.wikipedia.org/wiki/LED

On the other hand, incandescent bulbs put out an extremely BROAD spectrum, from damaging non-visible ultraviolet (<300 NM) to well beyond damaging high heat infrared! Even most colored or filtered bulbs have a high level of UV, and infrared. Some incandescent lights have more UV than other it all depends on the composition of the filament. For example, most halogens are twice as bad on UV emissions. Many Incandescent bulbs even have a higher rate of UV emissions than some florescent lights. http://www.nationalgallery.org.uk/ultra-violet-filters-for-artificial-light-sources  White LEDs, due to their lack of UV, do not attract bugs as do other lights. http://www.creeledrevolution.com/blog/tag/uv-radiation/

Also, since LED are virtually UV free as well as virtually infinity adjustable color-wise, they are now being used more and more in national galleries and museums. The equivalent of hundreds of thousands of US dollars are being spent be such galleries as the National Gallery of the U.K. http://www.nationalgallery.org.uk/about-us/press-and-media/press-releases/paintings-newly-illuminated-at-the-national-gallery for changing from incandescent to LED.

As for their use in plastic models … ANY incandescent bulb, has as MUCH as 100 times more UV radiation in plastic buildings than white LEDs,  and 100 times the damages from infrared (heat),  attract all types damaging insect,  energy-wise it cost almost 100 times the amount of LEDs to run your layout,  has to be replaced as much as 10,000 time sooner, and condemned by scientist for use in art galleries!  

So it makes you wonder, why are so many people are gunge-hoe about incandescent lighting in layouts?

Steve Johnson
Owner/Moderator: Realistic Train Modeling on a Budget
http://groups.yahoo.com/group/Train_Modeling_on_a_Budget/

A group for seniors, students and others on a fixed income. This is a brainstorming, think-tank sort of group for all scales to model REALISTICALLY on a budget, using ingenious, creative, Macgyver type tricks.