Digital BW, The Print

On a simpler note: EAM (acidic? paper) + Piezotone black ink + direct 
sunlight/UV radiation = brassing/brownish tints???

I would test the MIS inks and the other quadtone inks on EAM to see 
whether the EAM paper is at fault. After all the Epson inks are fine 
on EAM so far but EAM wasn't designed for Piezotones so any potential 
risk of printing piezography on it is bound to be unpredictable.