Hi Andre,
>Epson 1430 ... Eboni-6 inks, v1.1, from MIS ...
>Epson Ultra Premium Presentation Paper Matte ... 2880 dpi (and unidirectional printing)... the ink density higher,... the color cast is stronger.
That sounds normal.
>;Black-only is more neutral with b* values in mid 3s, compared to mid 5s or 6s ...
Yes, the dilute inks are warmer than the 100% MK. The Eb6-C (30% MK) is somewhat more neutral than the more dilute inks on many papers.
Unlike the original Eb6, the 2% Eb6-Y in the newer version 1.1 inkset is not more neutral than the other dilute inks. Overall the version 1.1 inkset is warmer than the original but still not as warm as most 100% carbon inks. Due to this increased warmth with the newer MK, the recent variants of Eb6 I'm made have a light blue toner ink in one of the positions to get us a good range of print tones from the carbon warm to neutral or even cool. These inksets are those with "Variable tone" in the names.
> Microbanding at the 1-inch margins seems to be worse with 2880dpi ...
Many of the modern Epson printers need 1 inch (at least) borders. I have not compared the different printing resolutions. I just use the wider borders to avoid the problem.
Looking at overall print quality, my past testing seemed to indicate the advantages of the highest print quality were worth the time waiting for the print. It's a trade off and may vary with the particular printer.
> [I]s there a black-only QTR calibration chart, where only the first strip is printed?
I always print the first, 100% Calibration Mode print because I want to see the full range of all the inks. I never print the second Calibration Mode print because all we generally use is the Black test strip printed at its ink limit. To do that, I make profiles that I call, for example, "K-0-45", that print just the MK ink and only to the ink limit indicated by the profile name. You can pull up one of these from my Profiles Zip file and see how it is made. Basically, if you just specify the starting and ending coordinates, for example (0,0) and (100, 45) (I use the Windows Curve Creator GUI to do this) QTR will print a straight line curve between these points.
>To find the initial black ink limit, where you only look at the black channel ...
Use the first Calibration print. The ultimate dmax is going to be shown there, where the print no longer gets darker with more ink. You want what I call the left edge of the shelf. After the ultimate ink limit the values will start to seesaw (swing up and down). You don't want to go there. As a practical matter, I often if not usually set the ink limit a bit below the ultimate dmax and then use the Black Boost for that final segment. It has a somewhat steeper slope and can be changed easily without affecting the rest of the profile. For example, if the ultimate dmax was at 45, I might set the K limit at 35 and Black Boost to 45.
To find the relative "density" values of the other inks, you use the first Calibration Mode print and compare them to the MK printed at it's ink limit -- for example, using the K-0-45 profile if 45 was your ink limit.
Determining the ink limits of the dilute inks is a bit subjective. For simplicity, try just setting the default ink limit at where the MK dmax was hit. Then use that for all of the dilute inks. The higher load MK always "clogs" the paper before the others.
So, for example, if the MK max'd out at 45, set the default ink limit there and measure all the dilute inks on the first Calibration Mode print at 45. Compare those values directly to the K-0-45 MK second print. Interpolate between the patches to get the intermediate values. Don't bother with more than 2 digit accuracy. The program is flexible enough to absorb some slop here. The cross-overs are very well designed.
Epson Hot Press is a good paper to use as a standard. (Note that third parties often make and/or package papers for other companies. The quality of the packaging, particularly for the larger sizes, is one element of competition. We don't like mashed corners.)
It sounds like you're on your way to very good printing. It's a long learning curve, but well worth the effort.
Paul