Digital BW, The Print

Hi Ernst,


>Paul Roark wrote:
>> I added a scan of a C86 MIS EZ test strip to the comparison 
>> between the R1800 and 2400. ...
>> See http://www.paulroark.com/BW-Info/R1800.pdf at p. 2.


>With the Multihead BO 1.5 picoliter printing there should be 
>more influence of dotgain by changing paper coating batches 
>and air humidity.

I'm not sure about the causation but what I see is more of a difference in
smoothness between paper types than I was at least aware of with the dilute
ink approaches.  Of course, I'm looking for artifacts, particularly
roughness due to the obvious fact that we're accustomed to dense inks not
printing smoothly.  Among the various batches of, for example, the Premier
Art 205 paper, including Epson's "Scrapbook" version of it, I'm not seeing
any significant differences.  I also print test strips from foggy mornings
to dry afternoons and after drying the previous test strip on the paper with
a hair drier, which I'm guessing simulates a very low humidity condition.
So, at this point I'd have to say that I'm not seeing sensitivity to
humidity or paper batch.  It may be that the amount of water that needs to
be absorbed by the coating is so much less than it is designed for that
humidity is a minor influence.

(Then again don't expect Somerset Enhanced to have smooth midtone grays --
or a competitive dmax -- in any conditions.)

One other thing I'm seeing that might be relevant to this issue is that some
papers that showed blotchiness with dilute inks look fine with the 3-Eboni
approach.  MIS Alpha, which is the Innova un-brightened coating on an alpha
cellulose base, is a dramatic case in point.  My favorite paper for several
years was the PermaJet Alpha, which was this same coating, but on a cotton
base.  It printed smoothly with dilute inks and had a wonderfully creamy
tone.  Then PermaJet pulled out of the U.S. market (when Jobo USA folded).
MIS tried to replace this, using the "Alpha" name on the alpha cellulose
base, but it never printed well.  It was a huge disappointment.  Now,
however, it's back.   The MIS Alpha looks terrific with the drier printing.

I've also noticed that I reach, at least with some papers, the dmax using
less total ink with 3 channels firing evenly than I do when I have one
channel carrying most of the load.  This reduces ink usage and makes
optimizing dmax much easier than it was when the Eboni channels were not
firing equally.  

> First of all its ratio between dot surface 
> and total dot circumference shows changes faster

I'm not sure I follow why they'd change faster.

>and the black ink has little transparency

That, I think, is the key.  Ideally, I'd like little black holes.  It's the
minor transparency at the edges that is, I believe, one of the remaining
sources of warmth.  When you look at the 100% black tones, it looks like
Eboni has very little warmth.  At the other extreme, when diluted, it's as
warm as any.  I think the smaller the edge transparency the less influence
on tone the carbon will have.  As such, the ratio between the area and
circumference is probably why the 3.5 pl 2200 dots print a bit more neutral.


> so its dotgain will have a 
>high density while the spots from where there ink migrated 
>will not become more transparent either.

Again, I'm not sure.

> Quite a difference 
>to large dots with diluted inks where the lower dotgain and 
>more ink transparency dampens dotgain influences (but 
>affects detail contrast). I thought way back when we 
>discussed this in theory that it could be a problem. I 
>wonder what it is in practice.

>At the same time the small black dots give the graphic 
>qualities Clayton liked: paper color less filtered overall, 
>ink color hardly visible, high detail contrast.

The less-filtered paper is mostly what I'm seeing.  The paper becomes even
more important.  Again, I'd like little black holes with no color at all.
Eboni may be the best we can do with current technology.  (I would like to
test some other black inks, however.)  It's rather ironic that after all the
variable tone inksets I've made to help control the tone of the print, I'm
now taking a totally different direction.  However, it was really fighting
that carbon warmth that was behind all of the other efforts.

>An interesting advantage could be the very low use of ink 

Yes.  As I've mentioned, a purist B&W printer could have 2 bottles -- Eboni
and cleaning fluid, and keep a printer running a very long time for very
little money.

The reaction of the old darkroom B&W printers (of which I'm one) has been
particularly gratifying.  Getting away from any color inks or color
profiling really appeals to them (and me).  "Black and white" once again
means just that -- black image forming substance (even if carbon particles
instead of silver grains) and white paper.

>and by that of inkmedia so reducing outgassing to a minimum 
>when framed.

I've never had a problem with matte paper outgassing.  The glycols that
cause the outgassing apparently have a great affinity for cellulose.  So, on
the non-barrier papers, they seem to latch onto the paper and just stay
there.  I have wondered, however, what impact they have on longevity. 

Paul
www.PaulRoark.com