Digital BW, The Print

Thanks to everyone for their comments.  I thought it was cool that
Paul himself posted... I am humbled!  :)

Just to clarify, I am using the combination of Photo black with
Kirkland glossy paper, NOT the Eboni black.  I think one of the
posters misunderstood my question to Mike J.

It definitely seems to have something to do with the transition from
the areas of the print which go from medium/dark grey to black.

Could it be a problem with one of the print heads, I wonder?  It's a
brand spanking new printer, so I suppose it's unlikely, but stranger
things have happened.  Hmmm.. maybe I'll generate a digital color
image which has cyan, magenta, yellow and black squares and try
printing it.  Might yield something interesting.  (Or might not).

Also, I will post a scan of one of the prints which exhibits the
problem clearly - maybe seeing it visually will give a clearer
indication of what might be going on.