QTR-Quadtone RIP

This message concludes my quest for profiles for Moab Kayenta for
Epson 4000 with UC inks.  Along the way, I've built 24 curves (12 each
for warm and cool - none for sepia and selenium, sorry) and linearized
six.  The final two QIDF files are now in:

	Files > Curves > Epson 4000 > MiloUC.zip > MoKPM205

along with:

	MoKPM205_Densities.xls
	MoKPM205_Versions.xls

spreadsheets documenting the exploration.  A pair for Crane Museo
Silver Rag is also included in MiloUC.zip > CrMSR.  If anybody else is
out there using this antiquated printer and inks, perhaps these files
may be useful.

The fundamental problem was achieving decent dMax without muddy
shadows.  Some suggestions from forum members proved useful, so – in
the spirit of sharing for the common good – herewith is a summary of
what I tried and learned.

First, a note about notation.  Labels such as "Ink030-Cool-V1Linear"
and "Ink045-Warm-v12" refer to version tags and worksheet labels in
the spreadsheets.  Since only the truly motivated will download and
unzip these files, here are a few notes to guide the exposition:

[Ink100] – Unlimited ink separation.  By eye, I chose 045 for Default
Ink Limit, which exactly matched Duane's subsequent suggestion to stop
when density increment falls below 0.03.

[Ink045], [Ink045-{Warm,Cool}-v1] – Limited ink separation for 045 and
first two curves.  Respectable dMax (1.60 warm, 1.57 cool), but muddy
shadows.  So, as reported earlier, I set the goal of finding a Default
Ink Limit that would produce distinguishable transitions to 100 in the
ink separation. I tried 40, 35, and finally 30... which was easily
distinguishable to 90 and barely to 100.

[Ink030], [Ink030-{Warm,Cool}-v1{Linear}] – Limited ink separation for
030 and first two curves plus linearizations.  Great shadow detail,
but disappointing dMax (1.54 warm, 1.49 cool).  What to do?  Duane had
cautioned against pushing Black Boost any further and had mentioned
limiting Light Black instead.  I didn't pick up on that at first. 
Instead, I decided to go back to 045 and explore increasing Shadow
(ultimately a dead end, as we will see).

[Ink045-{Warm,Cool}-v[2-5]] – Versions for Shadow = 12, 18, 24, 300
(maximum allowed), all with Default Ink Limit (045) for Light Black. 
Still too muddy in the shadows.  Finally decided to tinker with LK Limit.

[Ink045-{Warm,Cool}-v[6-11]] – Versions with Shadow = 300 (mostly) and
LK Limit = 40, 36, 30, 25, 20.  V11 (Shadow = 300, LK Limit = 20) was
nice.  Good shadow detail and impressive (for this matte paper) dMax
(1.64 warm, 1.62 cool).

[Ink045-{Warm,Cool}-v11Linear] – Now linearized and compared with
ideal.  Not bad.  Tempted to push LK Limit below 20, but that seemed
extreme.  Should I have gone lower?  Tempted to stop and declare
victory, but wondered if Shadow = 300 was really necessary.

[Ink045-{Warm,Cool}-v12] – LK Limit still at 20, but Shadow back to 6.
 Graphed against earlier v11 with Shadow at 300.  Unlinearized curves
clearly show some Shadow contribution to lightening – but more in
midtones than shadows, where I had expected it.

[Ink045-{Warm,Cool}-v11..12Linear] – Both v11 and v12 linearized and
compared with ideal.  Surprise!  Essentially no difference between
Shadow = 6 and Shadow = 300.  By Occam's Razor, v12 wins (the version
uploaded to Files).

Conclusions:

1.  Choose Default Ink Limit when density increment falls below 0.03.

2.  Black Boost no more than 1.15 * Default Ink Limit (actually 1.22
for my Warm version because I was using the old heuristic of +5 for
cool boost and +10 for warm boost).

3.  Leave Shadow alone.  By implication, leave Highlight alone?

4.  Try alternative LK Limits to maximize dMax and unblock shadows. 
With more gray inks than Black and Light Black, this would require
some actual understanding of what is going on when ink meets paper. 
Otherwise, the number of combinations would get out of hand quickly. 
How do you folks deal with that?

5.  In the end, the only important goal would seem to be to maximize
dMax and to mimic the ideal density curve for that value.  Are there
any other ancillary goals?

Additional comments and observations would be much appreciated...
because the next quest is to streamline this process and apply it to
the new kids on the block:

	Hahnemuhle Fine Art Baryta
	Harman Fiber-Base Alumina
	Ilford Galerie Gold Fiber Silk

No doubt their glossy natures will impact ink limits significantly. 
Any tips about that?  I also dread problems with bronzing and gloss
differential, but perhaps PremierArt PrintShield will help.  More
later as insights develop.  Thanks again for your patience and helpful
comments.