Digital BW, The Print

----- Original Message -----
From: "Robert Morrison" <rmorrison@...>
To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
Sent: Thursday, December 19, 2002 10:23 PM
Subject: Re: [Digital BW] UltraChrome Photo Black dmax


> On 12/19/02 9:08 AM, "Paul Roark" <paul.roark@...> wrote:
>
> >>> Does anyone have a good reading of the dmax of the UC photo black on
> >>> EAM/EEM? ...
> >>> The Archival K is producing only 1.48 ...
> >
> > Robert wrote:
> >
> >> 1.48
> >
> > So, are the Archival K and UC Photo Black the same stuff?  Epson told me
the
> > UC photo black had a higher dmax, but then Epson seems to say lots of
> > inconsistent things.  I'm guessing the two inks come out of the same
pot.
> >
> It is suspicisious...isn't it?!  I have a half full photo black 2200 cart
if
> you want it.  I don't really like the luster output...and have switched my
> machine over to the matte black so you are welcome to it if you want to
> test.
>
> Robert

Not without speculation but:

Reading the MSDS sheets of both inks there are some differences:
The proprietary organic materials (glycols and additives?) are at 18 % for
Archival black and at 8 % for Ultrachrome Photo Black. Both have more than
3% Carbon black but Photo Black has more than 5% proprietary black/pigment
as well. Archival Black just more than 1%. If there's dye in the Photo Black
then it isn't so strange that the organic materials content is lower in
percentage. Add the dye + the organic content and you get 18 % again. The
base then will be thick enough to keep more pigment suspended like in the
Archival Black.

One would think that there's no extra pigment needed when dye is already in
the mix. If you check the Grey Ultrachrome MSDS you will see stranger
percentages. The carbon black is <1% but there's <8% proprieatery
dye/pigment in the mix. The Matte Black has a proprietary dye/pigment as the
only colorant at <7%, no carbon black mentioned. So I guess the Matt Black
colorant is mixed into the other two blacks to a degree that makes gloss
printing still possible.

For the Grey you don't need any extra black to get density so there must
have been another reason.
Next to the Archival Yellow I still think that the transparent encapsulation
on the pigment particles played a role in metamerism of the Archival inks.
You either color that transparent resin or make the ink base less
transparent.
I thought they had done the first but it may have been the second after all.

Can this be checked with a chromatography paper test ?

When mixing quads of Ultrachrome inks it is worth checking what happens when
the base added is transparent. Is metamerism appearing again or not.

18 % or 8% are not written in the sheets but 15 - 20% and 5-10%, I
simplified that.

Ernst