There are two primary different kinds of blacklights, and both have their separate advantages as well as their flaws" ?I guess it all depends on what kind of blacklights you are looking for and for what purpose.

Incandescent Blacklights:

These bulbs are very safe, although it too much exposure" ?especially if one stares into the light from a short distance. Incandescent bulbs are the bulbs used for blacklights that are colored a deep shade of blue, and the color filters out almost all other visible light. In the case of the incandescent blacklight, it has been proven that more ultraviolet rays or "wavelengths"? emit through the glass, strange as it may seem, these dangerous rays are not blocked by the darkness of the bulb.

Some incandescent blacklights are more violet and others appear a bluer shade, but there are" ?within both" ?a significant amount of infrared rays that are much less visible, if you can see them at all.

An incandescent blacklight works well to illuminate blacklight art, such as paints and neon or light-colored pastels and printed colors used in paintings, drawings, posters, clothing etc.

Fluorescent Blacklights:

These blacklights use fluorescent tubes that emit a stronger level of UV light. The inner part of the bulb is covered with a phosphor substance which will absorb all UVC rays from the light, there are six kinds of phosphors commonly used I fluorescent lamps which emit longer "wavelengths"?.

A common glass used for fluorescent blacklights is known as "wood's glass"?. The tubes of these lights is much more transparent and have longer UVA and therefore shorter visible violet rays" ?there are the weaker of the two kinds of blacklights.

However, these "BLB"? lamps, as they are also called, can be used for special effects in theatres etc, best possible condition of their ability to make fluorescent objects glow very brightly.

Note: There are other kinds of ultraviolet lamps such as: UVB medicinal lamps, and UVA sun tanning lamps, and apparently incandescent Ozone Lamps.