You people are all wet. Stop misleading poor Mark Penney.
1. SAD light boxes are white visible light... no impact on acne.
2. UVB does not destroy acne bacteria... it stimulates melanin and vitamin D... and helps with psoriasis... no impact on acne.
3. UVA does nothing for acne... it just oxidizes melanin and "tans" you.
4. Red and IR light is for collegen rejuvination... maybe helps acne "pits" but no cure.
The ONLY wavelengths that FIX acne are blue light 415-435nm. The bluish light you "see" from tanning lamps is 405 and 435nm....so it does work but not super good.
You can google " acne lamps " and find the "real thing" like they use in derm offices. I doubt if a blacklight "bulb" qualifies... but it would have a few 405nm rays.
Spam alert: You can check how much acne-cure rays with Solarmeter Model 9.4 Blue Light meter:
http://www.solarmeter.com/model94.html