>    
   >    
   > All kinds of stuff absorbs at 460 nm.  You might try the 578 nm    
   >    
   > haemoglobin absorption peak, and compare it against something nearby,    
   >    
   > like 600 nm.   
   >    
   >    
   >    
   > Cheers   
   >    
   >    
   >    
   > Phil Hobbs   
   >    
   >    
   >    
   OK thanks. Please allow me to spell out the reason for the nearby comparison   
   at 600 nm. Actually, I'm not sure. I note from spectrum of Hb that the ext.   
   coeff. is less in the red (600), so this would give a base number of light   
   that is not being absorbed    
   as strongly? TIA JB   
   >    
   > --    
   >    
   > Dr Philip C D Hobbs   
   >    
   > Principal Consultant   
   >    
   > ElectroOptical Innovations LLC   
   >    
   > Optics, Electro-optics, Photonics, Analog Electronics   
   >    
   >    
   >    
   > 160 North State Road #203   
   >    
   > Briarcliff Manor NY 10510   
   >    
   >    
   >    
   > hobbs at electrooptical dot net   
   >    
   > http://electrooptical.net   
      
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