Digital BW, The Print

----- Original Message -----
From: "Paul Roark" <paul.roark@...>
To: "DigitalB&WPrint" <DigitalBlackandWhiteThePrint@yahoogroups.com>
Sent: Monday, September 02, 2002 1:57 PM
Subject: Re: [Digital BW] Media Street Black + FS-N was PiezoTone Selenium
300 Hr Fade test


> Martin,
>
> You wrote:
>
> >I really am beginning to wonder if the PT-K and the Gen-K are not the
same
> >ink. ...
>
> >Also check out Paul's fade testing of the Gen and Indelible blacks in
> >folder:
>
> >Files > Ink Sets > MIS
>
> >and then take a look at his fade test of the PT-K, PzoTone-VM-FS-K-100
> >hr fade test.jpg , in folder:
>
> >Files > Ink Sets > PiezoTones > PiezoTone vs MIS-FS
>
> >...
>
> Although comparing test strips from different runs of the fader increases
> the chances of other, random factors influencing the results, the two
tests
> you noted above suggest to me that PT-K and Gen-K are not the same.  The
Gen
> K seemed to perform much better.
>
> Note also that the control test strips (both K-only on EAM) are much
> different.  The Gen-K has a visual density of 1.82, while the PT-K has a
> visual density of 1.74.  The Gen-K also is 0.02 units cool at the 100%
spot,
> whereas the PT-K is 0.03 units warm.  Note that the cool black of the
Gen-K
> would make it a better fit for the "selenium" tone due to this cool black.
> (This is on EAM.  Results on PhotoRag may be different.)
>
> Gen. Enhanced K is the one I recommend to others who want a deeper black.
>
> I do think the inks are similar in that they appear to be hybrid
pigment-dye
> inks.  That alone might make the separations you've seen in water appear
> similar.
>
Paul,

Thanks for the info on the inks and the Gen-K performance. Could the Dmax
difference is a driver issue? We know the Piezo plug-in always seems to give
up 0.1 in density.

My problem is that I like the warmth of the black in the ink but I guess
that I could duplicate that by adding a touch of M and Y pigment ink to the
Gen-K or VM-K with out getting into the tricky density issues associated
with tinting the gray inks.

Where does the MIS Double Density Black fall in comparison to the Gen, VM
and PT blacks?

I looking at the VM-K and ST-PT-K there are no visual clues but as soon as
you start to rinse the ST-PT-K the water goes red/purple in the dilute areas
which would seem to indicate that the warm component is a separate
component, possibly a water soluble dye or possibly a pigment but that water
dilution causes separate from the dispersion due to particle size or surface
tension differences.

I tried a drop on a piece paper towel and on EAM test. There is no
separation at the edges of the drop like we saw with the original Piezo so
that would seem to indicate that it is not a dye or that it is tightly held.
I also tried putting a single drop of ST-K into an ounce of MIS Clear Base
and let it slowly disperse a bit. It showed no sign of separating and after
mixing produced a very, very light gray when swabbed on paper with no
separation. The ST-K is visible warm to my eye at full strength and diluted
once it is on paper.

Does that give you enough info as to chemical compatibility between the PT
and VM inks? The small 50/50 mixture I made last night seems fine today.
Hasn't turned into super glue or anything odd. Hard to say with out real
data but the viscosity and surface tension seem unchanged.

Martin