QTR-Quadtone RIP

hi,

I've purchased a Mac mini with leopard. Installation of qtr went ok  
and the printing works, but prints are too dark.
I used LightZone, application managed colors, qtr_gray_profile and UC  
inks on stylus R1800 with epson archival matte paper and used eenh  
black curve. Does this have something to do with mac gamma 1.8?

Any help appreciated, because printing on mac is much faster than on  
my windows box.

tia

-matti