Digital BW, The Print

yep, Photoshop 4.0.(a work provided emac but with antiquated version of Photoshop) 
which predates adobe RGB 1998 and excludes it as a color space as far as I can tell.  So, 
I'm very, very new at this, set up the inks yesterday, plugged in some roark curves and 
well, things aren't looking so good. Shadow detail seems as if it's solarized. When I print in 
BO, lots of banding (nozzle check and alignment are fine and this doesn't happen when I'm 
printing RGB). ANy thoughts, words of wisdon and/or encouragement?