Digital BW, The Print

Hi

I am playing around with some curves for my 4800 and am a little stuck on cool selenium's 
desired tone.  Presumably with a cool curve we want a direct shift into CIELab's negative b 
(blue) territory (with relatively neutral a).  For sepia, a shift to +b (yellow) and +a (red) or 
thereabouts.  How would one describe, in these terms, the difference between warm and 
sepia?  Now coolse.  I assume this is really a shift to -b (blue) but with a hint of +a (red) but I 
don't have a good benchmark to compare against.  Any thoughts or comments would be 
appreciated.

Steve