Digital BW, The Print

Maybe the final word on his ink belongs to Jon Cone (from the 
Color Piezo newsgroup):

"We have thought about coming out with a more traditional 
pigmented BW ink  which would incorporate more dye into the 
mix; supplied to those who wish to print on glossy materials. But 
longevity of such an ink would be compromised in favor of 
compatibility with more traditional looking photo gloss materials. 
Our current BW ink, being a very heavy and concentrated pigment
base is just too dense for gloss materials (and we have had the 
best minds in paper development working on alternative gloss 
technology to no avail...)

Pros and Cons:

Pros of a dye in a pigmented ink, is tinting strength as it reflects 
back less white light than pigment - it appears darker or more 
saturated to the eye. It allows for customization of a 
monochromatic ink. If heavy in presence will allow printing on 
gloss coatings and allow for greatest paper compatibility.

Cons of a dye in a pigmented ink: metamerism, reactions to 
paper coatings disproportionate to their presence (i.e the 
chemical compound of the dye molecule and the coating mix 
produce a reaction - this can occur whether lots of dye or trace 
dye.
-- 
Jon Cone"

     Jon had perfectly good reasons for going with pure 
pigment--deciding, that is, not to use a black ink that "appears 
darker or more saturated to the eye." How critical the difference 
in apparent blackness is to an individual printer is a subjective 
matter. The fact that the difference exists seems indisputable.

I'm still very interested in seeing samples of the deepest blacks 
people have produced with Piezography inks, using white matte 
fine art papers. I'd be happy to pay for them. I'm not actually a 
fanatic about these things--I'm just looking for the best ink/paper 
combination for my work.

--David