Digital BW, The Print

From: Clayton Jones <cj@...>
 To: DigitalBlackandWhiteThePrint@yahoogroups.com
 Sent: Thu, 06 Oct 2005 05:09:36 -0000
 Subject: [Digital BW] Re: question about CFS systems - K7?

 Hello Bill,

 >With respect to smooth tonality and local contrast, can you describe
 the difference between K3 ABW and K7? Any other comparisons you think
 are worth mentioning?

  Clayton, I'm not qualified to answer all the questions in your post 
but there are a couple of observations and opinions I can pass along.

  It seems that many questions about grayscale printing with inkjets are 
rooted in two basic and overlapping issues:
  1. The color tint of the print and any color cross-over issues that 
might be apparent when printing grayscale with color ink sets.
  2. The tonal structure of the print. This includes dmax and dmin 
("print black" and "print white"), controlling the transition points 
between the inks (tonal smoothness), and the issue of local contrast.

I guess we could consider matching the on-screen display of the image 
to the print to that list, but for brevities sake I'll ignore it for 
the now.

  Color first. I've always had trouble with the concept of a "neutral" 
print. To my eye, Cone's K7 inks are the "most neutral" I've seen and 
there is no observable color cross-over. There still is with K3/ABW but 
its marginal and easily camouflaged, making it an excellent OEM 
solution (and I think there is a lot of merit to that). It may be worth 
mentioning that recently I did a series of test using IP, QTR (older 
version) and Bowhaus, with the respective canned print profiles, to 
print grayscale using the UC inks in a 2200. All produced good, 
acceptable prints. Minimal color-crossover and acceptable color tint 
(each print was a different color, none where neutral to my eye, but 
all were okay). Using the canned print profiles with each RIP, the 
Bowhaus produced better tonal structure: tonal transition seemed more 
or less equal but Bowhaus produce a print with better internal or local 
contrast. I thought that was an important difference.

The best results, printing grayscale with UC inks, came from using 
ColorBurst. The canned ColorBurst environments (a linearization file 
coupled with a print profile) are excellent. Our custom authored 
environments demonstrated an observable difference, but not one you'd 
likely notice unless you had the prints side-by-side. I like ColorBurst 
because I can print grayscale and color through the same machine, ink 
set, and RIP. Our custom profiles were authored with an EyeOne 
spectrophotometer and MonacoProof software. I should also clarify that 
the IP, QTR and Bowhaus test prints did not benefit from linearization, 
like the ColorBurst prints did.

Right now, I like the K7 inks enough to consider dedicating my 7600 to 
them and purchasing a 7800 when they become available.


 >My understanding is that K7 has
 enough cool toner added to be neutral on PR. If that is correct, it
 means that K7 is cooler than Eboni. So how warm can K7 get? What
 does it look like on PHP? And what happens to it on a cold paper like
 CBW? How wide a tonal range does K7 have?

So far I've printed on Photo Rag, Bradford Bright White, Bradfore 
Bright White dual sided, and Bradford Natural White (and a couple of 
other odd papers I found in the studio). The print color is decided 
unique with each. The Bright White dual sided is scary close to the old 
Oriental Seagull or Kodak Elite papers toned in selenium. The Natural 
White reminds me of a ligthly toned Kodak Ektalure print. I'd have to 
say that the Photo Rag print is the most "neutral" to my eye; but the 
print on Epson Enhanced Matt is also good.

The nice thing about this system is that you can standardize on the 
inks and experiment to find a paper stock that works best for you.

 >Related to this, in BO printing where uncoated paper shows through
 between the dots, the paper color is an active and major contributor
 to the over all tone, and also adds BO's characteristic luminance. In
 full ink systems much less bare paper shows so there is a more opaque
 look and the paper color is subdued a bit (doesn't have as much
 influence), but some systems are better than others. For example, I
 am pleased with the luminance of the 2400 K3 prints. It's really
 quite good for a full ink system, but of course paper color is less
 influential than in BO. Can you describe how K7 does in these areas?

I know this is completely subjective but I've always thought that 
well-made quadtone prints have a luminance that is generally missing 
 from grayscale prints made with color ink sets. There is a difference 
in the density of color (even using the best custom profiles through a 
good RIP).

 >Again re color tone, does K7 shift equally in mid tones and darker
 zones when going from paper to paper? I guess what I mean is do all
 the inks shift equally?

I believe they do. Cone could certainly provide more insight to this 
question. I'd like to know, for example, if what I'm seeing is directly 
related to the ink or to the way the ink is applied to the paper. Hope 
that makes sense.

 >When changing to other papers, there is more going on than color
 shifts. There can also be changes in contrast, density and dmax. How
 do you adjust for these other differences in your workflow? Do the
 profiles take care of that or must you make some image adjustments?

So far Cone's canned profiles through QTR are working very well, which 
does allow one to make reasonable, if subjective, judgements. There are 
differences in dmax and the color of the paper stock definately 
influences the eye. But the overall density and contrast of the test 
prints were very well matched.

 >With K3 I find that there are certain critical ABW settings for each
 paper that eliminate the "colorized" look (where the print has a color
 tinge to it). I wrestled somewhat unsuccessfully with this with UT7,
 but with ABW I can make minute adjustments to find a setting that
 eliminates it. Since K7 must have toners in it, is this ever a
 problem? Do you feel handicapped not having variable tone control?

I think the K3/ABW and K7/QTR approaches are very different. Ideally, 
you'd like to produce test prints on both. I've done this and like the 
results both ways. As I've mentioned previously, ABW is--in my 
opinion--a signficant development. Its the first OEM grayscale solution 
that I could use and be happy with. I also like the fact that I could 
make excellent grayscale and color prints from the same machine without 
the expense of a third-party RIP. Very nice. I could easily envision a 
project where using ABW would be appropriate. Given a choice, however, 
I prefer the prints I'm making with K7.  It's nice having the option.

Let me know if you have any other questions. I do have one idea: I'd be 
happy to produce a set of test prints with K7, when my CFS and bottle 
inks arrive. I could send them to you, Clayton, and you could then pass 
them along to anyone else on the list that is seriously interested. It 
would certainly help to suppliment my opinion with others.

Bill Kennedy
Austin, Texas