I haven't tested the Epson Hot Press, but I've measured countless ink separation images over the last few years. I've been doing tests all day today with Canson Edition Etching shows that the STS Matte Black (v1.1) reaches 1.71 at 30% and a Dmax of 1.73 at 65% before falling back down to 1.56 at 100%. I've included a series of Lab_L measurements of the black channel's ink separation image as an example, but after checking a handful of measurement files I keep for different papers, they all exhibit similar densities for the black channel.
96.93
46.98
38.75
27.95
21.46
18.81
17.50
16.67
16.30
16.14
15.93
15.82
15.72
15.72
15.65
15.63
15.71
15.92
16.41
16.69
17.24
Take a look at this post I wrote a few years ago. The graphs can illustrate what I'm talking about here: Comparing Cone Piezography Shade 1 and MIS Ebony Shade 1. The post uses the old version of the MIS MK, but I have STS MK v 1.1 in the K channel now. I will do an updated post with the new ink at some point... I don't have a full set of the v 1.1 inks here, but I do have some clear base on hand I could use to mix up the STS MK. We'll see how distracted I get this week...
Richard Boutwell
http://www.richardboutwell.com/