Steve:
 
NIH-Image is an 8-bit ONLY program.  You won't be able to get more than 8-bit
information into the program.  16 bit images can be loaded, but only after being
scaled (automatically or by the user) to 8 bit images.
 
There is (I hear) a version of NIH-Image which works with 16 bit images that was
developed by Molecular Dynamics (MD-Image).  I have not actually used it, but I
got a card from a MD person you could try contacting about the program.
 
Kurt Harris
Molecular Dynamics District Manager
800-333-5703 ext 7310
408-773-1222
408-773-1493 Fax