Mike, I played around a lot with B&W and seems my Epson printers (3) need a kick from the blacks which I can do with the Curves.

However, I tried your suggested method of working the math to fit 21 steps as used with "Quad Tone Rip" or QTR (They supply the 21-step wedge images within their download) and it isn't easy as it messes up the nearest one to the altered one.  The range is just too limited in QU.

Ideally, 21 steps as used by QTR, x-rite, Stouffer, Jon Cone, Keith Cooper, etc. would be easier to work off of to get the black inks in the Epson to form a nice linear gray tonality which it appears they cannot without a curve modification.  Even my local lab who prints with the 9900 cannot get a smooth tonality in B&W.  It's sharp, but just not linear.

I've attached what looks to be my "average Curve" working in QU.  Seems Epson needs a quick boost coming off the black (lower left) else the shadow detail get buried.

Would be nice to expand that "Curves" windows in QU from 16 steps to 21 to accommodate them since they all seem to think 21 steps is some sort of digital norm.  I don't even want to try the 51 steps as it will be a disaster.

Mack