Digital BW, The Print

Hi Joost,


> Thanks, this sounds like VERY cost-effective approach.

Carbon-6 is definitely still in the experimental stage.  On the R220 I
get very nice prints.  Yesterday I set up a 2200 with one of those
super-cheap SuperJetUSA CISs sold on eBay.  The CIS is rather lacking in
instructions (a CD was of some help, but did not cover the 2200 nor how
to prime the empty carts -- more on that below).  I'm not sure what the
European CIS situation is.

So far I've only made a single test strip with the 2200 Epson driver and
no profile, but under a loupe there appears to be some microbanding.  I
don't think it's visible in normal prints, but we'll have to see if a
proper profile takes care of it.

In general, I know the Photo Flo surfactant is a bit weaker than what is
usually used in inkjet inks.  It looked like it'd be OK for non-1.5
picoliter printers, but that is one of the things we'll have to
determine.  In general, it appears that the smaller the droplet and the
faster the printer, the better the surfactant needs to be.  Of course,
this also warms up the print, as the warmth appears to come from the
edges, which spread more if the surface tension is lower.  This warmth
is not desirable with carbon if you want to print a neutral B&W.   So,
the selection of base and surfactant type and amount is a double edged
sword.  The base used for Eboni-6 is actually an old formula.  The newer
ones don't work well in terms of keeping the warmth down because they
are made for the newer, faster machines with smaller nozzles.

If C-6 needs re-working with respect to the surfactant, Eboni-6 is the
commercial version that is close to the same (slightly different mixing
ratios).   It prints very smoothly in all the printers I've tested,
including the 1.5 pl models.  It is now available in bulk from MIS.  (I
have not tested a mix of the two bases.)

With respect to surfactants, I've found 1% isopropyl alcohol provides a
very marginal improvement in the smoothness.  That will be the first
thing I try if it turns out the Photo Flo by itself is not smooth enough
in the 2200.

The first Dow surfactant I tested worked great, but has a couple defects
that that caused it to be dropped.  I have a second one for testing now.
However, one reason I'd like to stick with the Photo Flo is that it's so
well known and tested long term in imaging products, where we'd know if
it had negative effects.  Keeping the chemistry, mixing and profiling as
simple as possible are clearly goals here.

With respect to the SuperJet CIS, I found it easy to prime (get the ink
in) by just filling the tanks and then using a syringe with a modified
MIS bottom fill adapter on it (see
http://www.paulroark.com/BW-Info/Mod_Bot_Fill.jpg
<http://www.paulroark.com/BW-Info/Mod_Bot_Fill.jpg>  ) to pull the ink
through and into the carts.  I held the cart upside down so the air
would be pulled out of it.  (The bevel cut on that bottom fill adapter
shown above can be done with sharp scissors.)

An interesing aspect of the CIS design is that the syringes they profide
fit tightly in the tank air inlet hole.  As such, I had one channel
where the nozzles were mostly gone.  Clearly I had a major air bell in
the system.  To avoid having to do too many cleanign cycles to get the
air out, I used the syringe to pressurize the tank of the mis-firing
channel during a cleaning cycle.  It appeared to work well.  The first
page through the printer after this had some ink on it, but I'm guessing
pressurizing the tank saved a lot of cleaning cycles.


> How would you position the Carbon-6 versus the K4+ for the 2100?

C-6 and Eboni-6 are matte paper only, 100% carbon pigment inksets.  So,
while they have a nice range of tones on matte papers, there will not be
the flexibility of an inkset that has color channels available for tone
profiling.  Of course, being 100% carbon monotones makes the C-6 or
Eboni-6 inksets much easier to profile and more stable, with no color
artifacts or weaknesses in that respect at all.  In the 220, they are
the smoothest inksets I've ever used, comparable to the K7 test strips I
have.

> ...I can
> can also see a hybrid: 3-5 carbon densities + some LM and (L)LC to
> get the ultimate neutral.

Eboni-6 appears to be incompatible with some modern inks.  Carbon-6 has
not been tested with such.  Base compatibility is one of the issues with
respect to clogging.  When incompatible bases mix on the parking pad
they can lead to clogs.  If you ever had a used 1280 that you put Eboni
in you'll know what I mean.  Until the dyes were rinsed from the pad,
the result was bad nozzle checks rather regularly.

> I've not so much interest in toning any more ...

That's one of the things that happened to me also.  The novelty of print
tone control wore off.  Now I'm more in the mode of getting "back to
basics" -- B&W photography and printing.  Getting the color out is part
of that.  But, the usual carbon pigments were just too warm when
diluted.  So, these 2 inksets -- Eboni-6 and Carbon-6 -- basically use
the most neutral carbon I've found with bases that preserve most of that
neutrality on at least some papers -- not all.  Paper choice becomes key
to tone here.

Paul

www.PaulRoark.com <http://www.PaulRoark.com>







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