Sciencemadness Discussion Board

Wood's glass

hyfalcon - 18-3-2014 at 19:29

This is to be used to filter out the visible spectrum from a black light LED flashlight. There is still enough visible light coming off these LED's that it washes the mineral florescence right out of the mineral. Wood's glass is what is/was used in the mercury vapor black light mineral lights from yesteryear. Anyone have a lead on where I could obtain a 50mm/2in piece? I'm even capable of cutting and grinding a larger piece to fit IF I can find any.

jwpa17 - 18-3-2014 at 19:54

The photo store B H Photo Video lists a Rosco filter providing this for $8.95. It is "temporary unavailable." The Rosco site doesn't seem to list this filter. However, I noticed that their polyester filters generally have a transmission of about 40% from 370-400 nm, so you could, in principle, use a red filter. The "UV" LEDs don't output much red as I recall, so you'll end up with about half-intensity UV. Rosco USED to make a sample pack available for about $10. Of course, that was eons ago - sorry.

Also, FWIW, Wikipedia mentions that "black light" tubes have a similar transmission to Wood's glass (although not made of Wood's glass), so you could (carefully) cut a black light tube. Rather dangerous, though.

[Edited on 19-3-2014 by jwpa17]

thesmug - 18-3-2014 at 20:15

http://www.bhphotovideo.com/bnh/controller/home?O=&sku=1...
Is that good?

hyfalcon - 19-3-2014 at 03:45

Rosco filters won't do the job. They still allow some visible light through. All I'm wanting is the UV spectrum to come through.

Praxichys - 19-3-2014 at 04:30

Get a bandpass filter from Edmond Optics in the UV range:

http://www.edmundoptics.com/optics/optical-filters/