Black Light White??

[mark]

I could not find this in the archives. I went to buy my bulbs this morning from the site recomended by folks here and ran into something I did not understand.

I know the difference between BL and BLB but what is BL white? Is there just no funky coloring on the bulb?

 

[Dave Wooten]

Mark I don t know if this helps but the Fluorescent lamps in my UV light box are labeled F20!12 BL and under that the words Black Light....the lights look like a regular white fluorscent light (tube light 24 ") they are 20 watt lights General Electric. They came with my UV light box made by Bud Wilson at Photographer's Formulary.

 

[photomc]

Hi Mark, this is correct..BL bulbs (at least the ones I have seen) are white and look like regular bulbs. The BLB bulb (think it stands for Black Light Blue) are the cool purple/blue ones.

 

[Jim Noel]

Tubes designated "BL" appear white when turned off. They print slightly faster than the "BLB" which are the same with a purplish-blue coating.

 

[nworth]

Most phosphors appear white in ordinary light. When the fluorescent lamp is turned on, mercury in the lamp emits UV radiation that causes the phosphor to emit its characteristic color. In the case of the BL phosphor, the tube emits a wide band of color peaking in the near UV area where alternative emulsions are most sensitive. The BLB lamps have a purple filter to cut out most of the visible light from the BL phosphor, but that light is useful for photography, so the BL lamps are better for our uses.

 

[mark]

thanks folks. Things make sense now.

 

[gwatson]

Quick question: Are the BL tubes the ones they use in those insectorcutor thingys? Just before a buy a cart load.

Cheers

Geoff