Specularreflection

The optimal wavelength light to create a glowing effect is 400nm.  Fluorescent material will not respond as well to higher or lower wavelength light (such as the 365 nm peak wavelength emitted by fluorescent black lights.  Light emitted by SST’s LED Black Lights peaks at 400nm and is even good for fluorescing more difficult colors such as different shades of blue.

Items that glow when exposed to black light are usually coated with a special fluorescent (luminous) material that causes them to fluoresce under UV light.  What our eyes actually see is the UV light reflecting off of the fluorescent material and dropping into the visible light spectrum as it loses energy.

Notes forreflectionoflight

Black lights have a wide variety of uses.  Today there are even black light tattoos made with a special ink that is visible under a black light.  Common uses for black lights include:

LED black light fixtures are extremely durable and not hazardous if damaged.  Fluorescent black light fixtures, on the other hand, are very fragile and easily damaged or broken.

Reflection, refraction diffraction

Black light refers to ultraviolet or infrared radiation that is invisible to the eye.  Black light fixtures emit long wavelength UV-A ultraviolet light and are most commonly used for observing fluorescent materials.  The ideal wavelength for fluorescence is approximately 395 nm for most applications.

Common fluorescent black lights are made by covering a fluorescent light with a phosphor coating that only allows UV wavelength light through (the coating appears black).  Standard fluorescent lights operate mostly in the visible light spectrum with only a very small portion of the light generated in the UV spectrum.  The efficiency of a fluorescent UV light is extremely low (typically ~5% the efficiency of a UV LED light).

Refraction oflight

Fluorescent black lights emit a wide spectrum of UV-A light that generally peaks around 365nm.  On the other hand, LED black lights are made to emit a narrow band wavelength of light that typically peak at around 395nm. SST’s LED black lights peak at 400nm and have a very narrow bandwidth of 20nm.  This ensures that all the emitted UV light is “useful” for lighting fluorescent materials.