Digital BW, The Print

"Paul Whiting" <paulmwhiting@...> wrote:

> > It is easy to keep in suspension -- a defect with the Eboni-based 
> > inksets.
> 
> I didn't know this...

Nor did I -- thus the centrifuge to, hopefully, not get caught this 
way again.  The range of Lab L changes in a 30 minute spin range from 
0.03 % (HP-C6 LK [30% dilution]) to 30% (guess -- choke).

> does that mean we should agitate the cartridges
> from time to time?

Yes.  In normal use, desktop printers keep the dilute Eboni (both 
Eboni-6 and Carbon-6) well suspended.  However, if the carts are 
sitting on a shelf, they should be agitated, probably weekly.

> I use refillable cartridges and a friend tells me
> that their back and forth motion at start-up serves 
> to agitate them.

Exactly.  It's the wide format printers that are the more likely 
problem area.  I do still have Eboni-6 in my 7500, but the carts 
require manual agitation.  In all my PDFs I stopped recommending 
these inksets for wide format as soon as I discovered the problem.

> I know that with CIS you can shake the bottles occasionally.

Yes, and the problem really didn't show up in the 2200 I had with 
Carbon-6 for 9 months.  I agitated the bottles occasionally, and the 
carts do have ink in them that gets agitated.  So, the fluctuations 
in density appear to get averaged out.

It does not appear that the "settlement" is causing significant 
agglomerations of Eboni, it just gets darker at the bottom and 
lighter at the top.

Note that I'm still a big fan of Eboni MK.  I probably will never be 
able to test it long enough, but I would not at all be surprised if 
it could beat the HP neutral grays in a fade test.  The HP PK and 
grays are, after all, blended carbon-colol pigment inks.  The things 
HP has done, however, that I was not able to do with third party 
inks, include using very lightfast colors, balancing the fade rates 
to avoid tonal shift (see a discussion of my early efforts at 
http://tech.groups.yahoo.com/group/DigitalBlackandWhiteThePrint/messag
e/58048), and advanced pigment suspension via a new coating that 
stops the different types of pigments from stratifying.  

So, it looks like we have a new and superior PKN.  But, I still 
believe a good carbon that can actually print neutral without color 
inks (i.e., Eboni with a 1.5 pl printer and not diluted) will be a 
better neutral matte inkset.  But, until Epson makes a 1.5 pl wide 
format printer, I need a more stable insket for the 7500 (I'm tired 
of picking up the 7500 and shaking it), and I think many will 
appreciate an advanced, neutral and affordable inkset for their 
Epsons. 

 

> 
> I've been in touch with the National Register of Historic Places
> lately, and sent them a few 3MK prints on Moab Lasal done on 
> my R1800. It's tough to keep a dialogue going, they're rather 
> busy, but they do seem interested.

Do they do their own testing?

> After studying Wilhelm's site, I see he approves of
> the R1800 with K3 ...

Do you have a URL for what you're looking at?  I assumed he just 
tested the 1800 with OEM color inks in it.

> ...doesn't
> the K3 process, although carbon-based, still use some color pigment
> inks, thus weakening their longevity over against pure carbon?

The 2400 3K B&W "ABW" mode prints definitely use color.  I don't know 
of a 3K 1800 approach aside from the 3-MK one using Eboni, and I know 
of no fade tests of that by any commercial testing group.

> My basic thinking is that since carbon-based 3MK, with touches of
> color pigment, easily meet Register standards then pure carbon 
> should be a no-brainer.

Yes.  I'm curious where the "3MK, with touches of color" is coming 
from.


> I wish there were some way to get the 3MK process on 
> Wilhelm's charts.

So do I.  I've never had any significant contact with him.  My 
impression is that his tests are just too expensive for little 
outfits like MIS.  (It's a shame the supplier hasn't picked up this 
ball -- hint.)
 
> I'll be interested to see how your HP work develops. Perhaps that
> process will eventually make Wilhelm's list.

While I am convinced Wilhelm is very reputable and a very good 
person, I don't think he's a charity.  It would be great if he'd do 
some "pro bono" work, but I've never seen any indication of this with 
respect to the inks we use. 

Paul
www.PaulRoark.com