Digital BW, The Print

I made three test prints (each consisting of a 21 step wedge and a 
panel of 4 small images with varying tonal range) on Epson Premium 
Semi-gloss (Epson 2200 printer) for evaluation of the PremierArt Print 
Shield spray.  BO prints were made with the Epson driver at 2880 dpi 
and a 20% dot gain print profile.  QTR prints were at 1440x720 dpi 
Highest Quality from graycale mode in gamma 2.2 workspace.  The 
procedure was to spray prints with overlapping strokes going left to 
right across the long axis of the paper from top to bottom and then 
immediately rotate the paper 90 degrees and repeat spraying.  Waited 10 
minutes and then repeated the spraying procedure for a total of 4 
coats.  I also repeated this a 3rd time the following day on the QTR 
print to see if there was any further reduction in bronzing.  Here are 
the results:

BO print made with MIS Eboni:
Dmax 3 hours after spraying:  2.13
No bronzing
Very slight gloss differential visible in shadow areas
Visible "grain" in midtones (approx. 45-70% area of step wedge)
Highlight dots not visible to me without using a loupe
Overall print hue - neutral

BO print made with Epson UC-PK:
Dmax 3 hours after spraying:  2.41
No bronzing
No gloss differential
Slight "grain" in midtones, not as noticeable as in the Eboni print
Highlight dots not visible to me without using a loupe
Overall print hue - very warm

QTR print made with a "neutral" profile using Epson PK, LK, LC, and LM 
inks
Dmax 3 hours after spraying:  2.44 (2.47 after 3rd spraying the 
following day - total of 6 coatings)
Bronzing still visible, but significantly less than before spraying.  
Tolerance levels for this residual bronzing will vary and also depends 
on lighting.
No gloss differential after spraying
No midtone "grain"
Highlight dots not visible to me without using a loupe
Overall print hue - neutral/warm (shadow areas warm).  I have great 
difficulty controlling the warmth of the PK and LK inks with the LC and 
LM inks on semi-gloss.  The LK, LC, and LM inks also exacerbate 
mid-tone bronzing (there is none with just PK).  These are probably not 
the best inks for B&W printing on RC papers.  I think that a UT-2 
inkset for the 2200 with stronger toners and/or more neutral gray/black 
inks would help.  Although I didn't test the UT inks in this trial, 
previous experience indicates that it is also difficult to control 
bronzing and warmth of the current UT inkset for the 2200 on RC papers. 
  Note also that the spray treatments affect base density and linearity 
of the profiles, so probably best to linearize profiles after spraying 
and drying (assuming spray procedures are standardized).

I really like the smooth surface of the semi-gloss sprayed with Print 
Shield - as Paul noted it is very close to the luster of an air dried 
silver print.  I currently prefer the appearance and hue of the BO 
prints for busy landscapes or images without large, smooth mid-tone 
areas.