Digital BW, The Print

Cdtobie <CDTobie@...> wrote:
>
> I worked on the SG inks with Joe and with Lyson, (I was the second person in the US to receive a set) and have revisited them with Joe more recently. The real issues are as follows:
> 
> Low saturation inks are made by mixing color with neutral pigments,

Is this Lyson inkset pigment or dye?  I thought they had an older dye small gamut inkset.  They may present different issues.

> and keeping both equally in solution is difficult

If they are dyes, they may not separate.  If they are pigments, they may well.  HP went to great lengths, apparently, to match the electrostatic signature of the different pigments that make up its neutralized carbon Z3100/3200 PK and grays.

With the dyes I'm working with, I'm leaning to not using the blended black plus magenta due to an unknown risk of catalytic interactions.  I see no evidence of such, but dyes have been known to react even on the paper.  Presumably Epson, well aware of this, designed these pigments so that would not be a problem.  But, it just raises an issue that casts a shadow on the approach.

> (just ask Paul; he and I worked on several sets based on this premise for MIS).


See page 4 of http://www.paulroark.com/BW-Info/4K+.pdf .  The graphs there show what I consider a significant tone change rate for the blended MIS inkset I was using.  My reading on this issue indicated it was a known issue of electrostatic dispersion approaches, which most of our pigments use.  Note that this will not be a problem with desktop units where the inks are regularly agitated.  For wide format users, it probably means that the blended B&W pigments inks ought to be agitate, perhaps weekly -- which is what I do with Eboni-6 also.  It's not that much of a problem -- for those aware of it.  

Paul
www.PaulRoark.com