Digital BW, The Print

Greetings, group.

I've searched the archives, and have not come up with an answer,
although I imagine there is one there somewhere.

I've got a workflow using QTR with UT7 inks established, mostly on
premierart hotpress 325 gsm, and am very happy with most of the
results, as long as large black elements are not a major component of
the picture.  The dmax is such that if there are large shadow areas,
the print takes on a "muddy" feel. - High key prints, or those with
only small or diffuse shadow areas seem to look fine to me and other
viewers.

So the question is - does PremierArt print shield increase the dmax on
matte papers?  Has anyone had any experience with the PriemerArt ECO
coatings, and if so, does anyone know when the aerosol versions will
be available, and from where?

Thanks in advance -

Doug