RE: UV-exposure units/ UV LEDs:diagrams

Hello Earl, etc:
   
  The other unpleasant thing about high strength lights you can't see is the potential for eye injury. Not being aware of it because it's outside your sensory range doesn't mean it still isn't hazardous (analogous to IR lasers in CD players etc).
   
  There is a German company (Roither? Roither LaserTechnik?) that makes laser and led diodes in more diverse wavelengths than I see in the US.
   
  They have some 420 nm LED's, deep deep blue, still enough to see, that about nails the spectral peak (typ. 425 nm) for graded 'silver gelatin' paper. Some alt-processes work with blue, some don't.
   
  I haven't worked with blue light for focussing yet, but some people say it's almost disturbingly unnatural to look at...to each his/her own I guess.
   
  I think you're probably already aware if you get too far into UV range most glass attenuates it. I think falloff is roughly 56% (44% transmission) at 380 nm for non-UV-filtering window/picture framing glass. Of course, optical glasses are all different recipes.
   
  And remember (if it matters), LED wavelength isn't monochromatic like lasers...it'll be a bell-shaped curve covering a narrow bandwidth (LED mfr website probably has data).
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Received on Sat Nov 4 19:32:10 2006