Hi All,  We've are using these 0.7ND kodak wratten  #96 ND filters.   
   We can only get them from Tiffen.   
   (so maybe the name should be Tiffen Kodak Wratten...)   
   I went to reorder and found that the ~1.5" x 1.5" pieces we use in lots of 8   
   are going to be ~$10 each.   
   I'm contemplating a letter to tiffen, without much hope.   
   So I'd really like another solution.   
   These are used in student labs to attenuate a diode laser.   
   (I think there is ~3-5mW (typical) but I'd have to measure.)   
   There's a "real" glass 1.0 ND filter, to suck up most of the laser power.   
   And then a holder for the above pieces of plastic put in 35mm slide projector   
   mounts.  At 780 nm they are really 0.5ND filters, which seems like a nice   
   number.   
   Two gives you about a factor of ten.   
   (Sorry for the long winded wind up.)   
      
   Is there some other absorptive piece of something I could use?   
   Not too expensive and reproducible.   
   Most plastics used in lighting become transparent beyond 700nm or so.   
   Yeah I've thought about reflective things.   
   It seems too dangerous for a student lab.   
   (The reflective filter can spray most of the laser power around the lab.)   
   But if you have a reflective thing for ~$1 per square inch ~0.5ND...   
      
   George H.   
      
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