Digital BW, The Print

I know you can't tell me exactly what kind of paper this simply by my 
description...and you may not be able to identify it even if you held 
it in your hands...but I emailed my file to a place that offered to 
print it for me as a free sample of what they can do in B&W prints.
That was before I got my R2400 for Christmas.  Well now that I have my 
R2400 I printed the same exact file on Epson Enhanced Matte.  Major 
diference.  Either they tweeked my file or this paper is wicked 
diferent than EEM.  Here's the diferences between EEM and Mys (Mys 
equals mystery paper)

EEM - whiter paper based on the borders
Mys - warmer paper based on the unprinted borders
EEM - cooler or more newtral skin tone
Mys - warmer skin tone
EEM - thinner paper
Mys - roughly double the thickness and stiffer
EEM - physically feels smoother and looks smoother texture
Mys - physically feels and looks rougher textured.  not a pattern but 
randomized texture like drywall
EEM - blacks are black
Mys - blacks are far deeper and blacker like a deep dark velvet

what is your best guess to what this mystery paper is?  I just want to 
try some diferent papers based on your best guess.  I won't hold you to 
it cause I know it's hard to identify this way.