QTR-Quadtone RIP

Thanks for the help, that was really what I was asking (can I put ink in the zero position).  I’m trying to get consistent dot patterns in digital negs to make 4-color carbon prints.  I’m using Piezography Methodology 1 inks on an Epson R3000, but only three of the inks give grain-like dots so I’ve eliminated the others, making digital negs on Pictorico (which I hate BTW!).    It would help if I could increase my exposure times when I print the separations by starting with ink in the zero position and increasing from there, but it looks like that’s a no go.  It’s true, I can make a PS curve to fix this, but I was hoping to keep it in QTR and avoid the step.  Thanks again!  Scott