Digital BW, The Print

Hello Howard,

Sorry to come into this so late.  Have been busy all day & evening.

There are several things going on here.  First the dmax.  As Carl
said, Eboni has slightly better dmax than MK on most matte papers
except Epson ones.  So if you tried it on VFA the result might be
different.  Also, Eboni is a bit cooler than MK, which can make the
blacks appear darker to the eye.  Another thing is that in BO prints
the blacks are made from pure black ink.  With full ink systems there
is usually a mixture of MK and LK way down into the darkest zones,
only getting to pure black ink at RGB 0 and 1, maybe 2 (above 99%).  

Dmax tests that print patches of pure black usually show just as good
a dmax with full ink systems.  But in most real world prints even the
darkest areas only get all the way to RGB 0 in small areas, so there's
often very few places that contain pure black ink.  The end result of
this varies with different combinations of ink, paper, printer and
driver, but in general, most of the systems I've tried or viewed
produce slightly less dmax than BO, with normal images.  This is why I
use Eboni BO for all my tests in the Paper Chase article.

Next, the general look and feel.  BO prints are famous for their
intensity, or "pop", or whatever you want to call it.  Besides the
excellent dmax, there a clarity to the ink tones that comes from the
pure K ink without anything else blended in.  There is also the
incredible luminance or "glow", which is caused by the bare paper that
shows between the dots.  Because BO prints don't get to full paper
coverage (no more white specs showing) until around 85% or so (it
varies with the paper), this luminance extends way down into the lower
mid-tones.  The paper is reflective, so the resulting prints have this
wonderful clear, open and radiant look to them.  

Full ink systems don't allow this bare paper to show and as a result
have a slightly veiled or opaque look.  The degree of this effect, as
with dmax, varies with different combinations of ink, paper, printer
and driver.  The result is that a full ink print can look great until
you put a BO print next to it, and suddenly it looks weak in comparison.

What I like about the 2400 is that its prints have better luminance
than many full ink systems I've seen.  It allows more bare paper to
show between the ink dots in the highlights than many other systems. 
For example, I'm using the R2 ink sets in my R200, so I can do Eboni
BO and smooth full ink prints with it.  It's really quite good, but
the R2 prints are more veiled and opaque looking than ABW/K3 prints
because there is no bare paper showing anywhere except at RGB 254 and
255 (0%).   The ABW prints show bare paper down to around RGB 190 (25%).  

The resulting K3 prints are not as clear and glowing as BO prints, but
they are much better than many other full ink systems.  BO's great
weakness of course is the graininess, which can be a curse or a
blessing, depending on the image.

I'm very pleased with the R200/2400 combination.  I still use BO for
prints that look good with it, and the 2400 is producing really
beautiful prints that are wonderfully smooth with the three blacks. 
I'm finding it a good combination, but I do miss my trusty old 2200
because now I'm limited to letter size BO prints.

So you might as well give up trying to make a K3 print look like a BO
one.  It's just an excercise in frustration.  Just learn to wring the
most you can out of the 2400 and be thankful.

ps - there is still the possibility of getting good BO from a 2400
using a RIP.  I tried it with QTR last fall but the results were poor
due to a very coarse dot pattern.  Roy says the later versions have
better 2400 handling and maybe it's improved.  I've been too busy to
try it, but hope to get to it after the end of May when I'll have more
time.  I haven't given up on it yet.

Regards,
Clayton


Info on black and white digital printing at    
http://www.cjcom.net/digiprnarts.htm