QTR-Quadtone RIP

I'm still looking for heuristics for selecting the best Default Ink
Limit.  This seems to be an important first step, but the best
approach seems unclear.

To recap the discussion so far, I chose 50 for Crane Museo Silver Rag
(glossy paper) because the transition from 45 to 50 was the highest
that I could visually distinguish (even though PFP measured steadily
rising values to 100).

Quoting my original posting:

"Reprinting the ink separation page, limited to 50 this time, I could
see PK transitions up to 75 - but no further. I was tempted to go
back and try a lower Default Ink Limit, but I pressed ahead."

In the end, 50 turned out to be a reasonable choice.  Regardless of
whether I set Black Boost to 55, 60, or 100... the linearized curves
always produced good shadow detail.

So far, so good.

Then I tried the process again, this time with Moab Kayenta Photo
Matte (matte paper with OBAs, now discontinued, although still
available in large quantities, no curves in standard QTR distribution,
suggested by Moab for proofing Moab Entrada Bright - which does have
curves in standard QTR distribution).

Out of curiosity, I checked the Entrada Bright curves for the Epson
4000.  If Kayenta is for proofing Entrada Bright, then I'd expect
similar ink limits, right?  FYI, the ink limit for Entrada Bright is
50 in the QTR distribution.

So... when I printed the first Kayenta ink separation - unlimited -
and let it dry overnight, I could easily distinguish transitions to
40, barely to 50.  On the surface, that appeared to be in line with
Entrada.  However, I was a bit nervous and chose 45 instead of 50.

When I printed the second Kayenta separation - limited to 45 - and let
it dry overnight, I could easily distinguish transitions to 65, barely
to 80, certainly no further.

Recalling that I could see photo black transitions in ink-limited
Museo Rag up to 75 and still get good shadow details from the curves,
I pressed ahead.

Bad idea.  The 95/100 transitions for preliminary curves were only
barely distinguishable... not at all acceptable for shadow detail.

What to do?  Recall that ink limit 45 resulted in easily
distinguishable transitions to 65, barely to 80.  I set the goal of
finding an initial ink limit that would produce barely distinguishable
transitions to 100.  I tried 40, 35, and finally 30... which was
easily distinguishable to 90 and barely to 100.

Good idea.  The 95/100 transitions for preliminary curves were easily
distinguishable... excellent for shadow detail.

What about dMax?  Here are some interesting numbers:

1.62 - MK unlimited
1.57 - MK limited to 45
1.41 - MK limited to 30
1.60 - MK + LK limited to 45 (Warm, Black Boost=55)
1.54 - MK + LK limited to 30 (Warm, Black Boost=40)
1.57 - MK + LK limited to 45 (Cool, Black Boost=50)
1.49 - MK + LK limited to 30 (Cool, Black Boost=35)

Bottom line:  holding shadow detail in Kayenta gives up 0.08-0.13 dMax
compared to MK unlimited,  whereas Crane Silver Rag only gives up
0.04-0.06 - half as much.

Two questions:

1.  Do matte papers typically exhibit this behavior compared to
glossy?  I've only done one of each, so I really don't know.

2.  What about the Gray Curve tab?  So far, I've always left Highlight
= Shadow = 6.  Is it worth increasing Black Boost (even to 100) to
regain dMax and then increasing Shadow (10? 20?) to lighten the bottom
transitions?