Donald Qualls
Subscriber
I don't see how adding more channels to the mix would help any. That's just not the limiting factor.
From my limited reading, the major limiting factor is the opacity of the ink at normal application levels, as well as its UV absorption profile (the dyes in regular ink may not look the same in UV as in visible light). Ink with opaque nanoparticles at high density per droplet would be the densest -- but of course one is limited to what's compatible with the printer in use.