Digital BW, The Print

Jerry,

You wrote:

>Paul, hasn't Cone repeatedly stated his inks are pure pigment?
>I thought he had.

I thought his position was that there had to be some dyes in the pigmented
inks to give them proper color.  For example, the carbon black is said to be
brown with if no "dyes" are added.  I think that MIS or Media Street
originally came out with a black ink that was pure carbon, and it was not
well received -- too warm and not dark enough.

MIS has also stated that their inks contain about .5% "dye."  However, MIS
characterizes the "dye" in their inks as the colorant that coats the carbon
particle, which is the core of the pigment particle.  I have gotten the
impression that all these desktop pigments are carbon particles at the
center.  Even the color pigments apparently are carbon coated with a
colorant -- which MIS calls a "dye."  (Note, this is contrary to my
understanding that "dye" usually means in this industry a colorant that is
dissolved in the solution as opposed to a pigment particle that is merely in
suspension -- and hopefully kept there by the Brownian motion of the fluid
base.)

My understanding from MIS is that the coating on the carbon particle is the
only "dye" in their inks.  This is unlike some "pigmented" inks from other
companies, however, where there are also dyes added to the mix in addition
to the colorant/coating that is on the particle.  In these inks, the dye
would be dissolved into the solution, not a separate particle in suspension.
I suspect that Piezo is in this category, and that is why we see the
separation in the chromatography experiment.

However, I, again, am not a chemist and could be totally wrong on how these
inks are made.

Paul
http://www.PaulRoark.com









Paul Roark wrote:

> Andre wrote:
>
> >Here's a snippet from a recent Jon Cone message on the other list.
>
> >"DO NOT PRINT ON EPSON ARCHIVAL MATTE!  IT IS KNOWN TO TURN GREEN IN
> >THE PRESENCE OF OZONE"
>
> >So, what's a good replacement for EAM ?
>
> I suspect it is an ink problem more than an Archival Matte problem.  The
> context of Cone's statement is a battle over the increasingly famous
"green
> cast" problem(s) of Piezo prints.
>
> Look again at the comparison of ink dots made with Piezo magenta v. MIS VM
> magenta inks.  This is in the Files section of this forum.  Go to
>
> http://groups.yahoo.com/group/DigitalBlackandWhiteThePrint/files/
>
> then hit "Message Related Files" and look at file "Piezo-MISdots.jpg."
>
> The Piezo ink, I believe, has a fair amount of greenish dyes in it.  I
> beleive this "Kleenex Chromatography" experiment shows those dyes.  My
> interpretation is that the dyes, which I believe are in solution migrated
> through the Kleenex further than the pigment particles.  Now, again, I'm
no
> chemist and may be mis-reading this experiment's results.  However, my
fade
> testing also seems to indicate that there is a substantial dye component
to
> Piezo ink.  In my experiments it fades substantially faster than MIS inks.
>
> We know that dyes are susceptible to ozone.  We also know that dyes work
> better (fade less) on Epson Heavy Weight matte paper.  Archival Matte
paper
> was designed specifically for pigments, not dyes.
>
> So, I think what we have with the Piezo ink is a fair amount of dye and
> perhaps a mismatch between those dyes and the Archival Matte paper.
>
> Is there an easy and cheap solution?
>
> I found one that works for me -- switch inks.
>
> Of course, if it turns out other pigments also turn green on EAM paper,
then
> I stand corrected and will re-consider my generally positive view toward
> that paper.  However, until I find a paper that performs as well as EAM in
> my fade tester, I'm reluctant to give up what appears to be a great
bargain
> and excellent performer.
>
> Paul
> http://www.PaulRoark.com