Digital BW, The Print

Just ordered some more MIS ink and an extra cart to try this workflow. 
Just curious but can you see any difference in the finished print or is 
it just a question of longevity. When I print a 100 stepwedge using 
different ABW settings I find it difficult to see a totally neutral 
print. Hence a previous post asking for guidance. Maybe its my eyes but 
I see some colour. Would appreciate what you see. Perhaps I'm being to 
fussy!!

Peter

Hello Peter,

>When I print a 100 stepwedge using different ABW settings I find it 
>difficult to see a totally neutral print. Maybe its my eyes but 
>I see some colour. Would appreciate what you see. Perhaps I'm being 
>to fussy!!

No you aren't being to fussy, it's one of the challenges of making BW
with color inks.   As good as the ABW system is, it isn't perfect.  At
any given setting, the color balance may shift slightly along the
ramp.   I've found that these instances of what I call coloration are
most often apparent in the middle gray zones.  A high contrast print
with few grays areas can look neutral, while another print with same
setting on same paper but with large middle gray areas can look
pinkish/greenish, etc (this has been discussed here before - Tyler or
someone else might pop in here with a better explanation...).  

There also seems to be some sort of interaction between the colors. 
For example, when increasing the H value (towards magenta), at certain
points the print may look a bit less pink than on a lower setting.  My
theory is that certain colors "harmonize" at certain ratios, and there
is a balancing or canceling effect (I'm not saying this is what's
actually happening, it's just my attempt to describe an effect I see).

Suppose, for example, I want to increase warmpth and my goal is a
brown that looks brown, without any pink or green tinge.  I find that
at any given increased H setting, the amount of non-brown coloration
varies according to the V setting.   An H value of 6 for example, can
look less pinkish than at 5, depending on the V setting.

To complicate matters, these effects differ on various papers.  So
what works beautifully on VFA may not work as well on Dourian or
Merlin Natural.  And I'm assuming that K3 and K4 will be different (I
haven't used K4).  

So the bottom line is we have to experiment systematically and take
notes.  My experience is that every paper can have one or more sweet
spots where everything harmonizes and produces what I call a
convincing photographic tone that looks even across the ramp. 
sometimes they are easy to find, others more challenging.

BTW, this problem is not the exclusive domain of color inks.  I found
essentially the same problem, in a slightly different form, with UT7
on my 2200.  I was never fully satisfied with any of it's tones. 
There was always a bit of tinge or dullness of some sort that
I never could eliminate, and spent countless hours tinkering with QTR,
curves and ink mixtures (not to mention $ on ink/paper), only to crawl
back in failure to BO printing after each round to rest up and lick my
wounds before trying something else.  

I saw the same thing in print exchanges with prints from all the
different systems in use at the time (various inks, RIPS, papers,
printers and techniques).  Seeing a really convincing tone was a rare
occurance.  Nearly four years of constant frustration, which ended
with the 2400.  It took me a few months to figure it out (actually
still learning new things), but I finally arrived at a place where I'm
getting convincing tones and most of my energy is focused on the
photography and not on printing struggles.  

Aside from the tone issue, the 2400 has a really nice combination of
smooth gradation and luminance, avoiding the dull look of many full
ink systems.  ABW isn't perfect, but for me it's several orders of
magnitude better than what we had before.  I finally am back to being
a photographer and not a mad scientist tinkering endlessly in a
laboratory <g>.


Regards,
Clayton


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

Thanks Clayton for your thoughts. I remember you talking about this problem and the 
reason you liked BO printing. I tried BO when I had my 2100. I like the neutrality of the 
prints but those dots always worried me. When the 2400 came along it seemed that at 
long last I had a printer that could produced neutral BW prints. Metamerism has gone. 
Neutral prints nearly !! I have had a bit of a break from this forum due to work and am 
only just catching up with what you guys are trying. When going through old posts I was 
intrigued to read about the yellow cart trick. Have you tried this ? If anyone else has I 
would like to hear what you think. 

Peter

Peter,

>I was intrigued to read about the yellow cart trick. Have you tried 
>this ? 

Sorry, no.  I've been swamped with work and basically don't want to
rock the boat right now.  It sounds like a good idea, but would
certainly initiate a whole new round of testing to find the sweet spot
settings on all my favorite papers.  The prime motivation for it is a
longevity issue, and while I'd like to eliminate the yellow, ABW K3 is
still rated at least 110 years worst case, so it's not a pressing
issue for me.  I may do it some day, but right now I'm up to my
eyeballs in work and am extremely happy with the results I'm getting.
 So I'm going to stay put for now.

Regards,
Clayton


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

Peter,

>Just ordered some more MIS ink and an extra cart to try this workflow.

Did you notice my 9/11 and 9/13 posts?  It looks like the MIS EZW Yellow is
the easiest and best way to go.  The C84-88 yellow chip even works in the
2400, and the results are smoother than with LLK in the Y spot.  So, it's
very easy to try this. Just buy an EZW-Y cart (with chip), and plug it into
the 2400 Yellow spot.

>Just curious but can you see any difference in the finished print or is 
>it just a question of longevity.

The longevity issue is rather clear and is important to me.  

I suspect there are also issues of differential fade with more color in the
image, as sell as artifacts like metamerism.  The lower metamerism with less
color inks in the image is hard to quantify.  Several who have tried this
method report that they see the difference.

When it comes to the visual impression of an image, it's probably going to
take some double-blind tests to get the subjective dislike for color dots
out of the picture (so to speak).  As with the question of how sensitive
people are to the smoothness of the tonal distribution curves, it's hard to
get data. 

> When I print a 100 stepwedge using 
>different ABW settings I find it difficult to see a totally neutral 
>print. ... Maybe its my eyes but I see some colour. 

I think you are not alone in this feeling.  See page 2 of
http://home1.gte.net/res09aij/3D-Comparison.pdf

The "ABW" mode prints do not have a particularly flat tonal response curve.
I think an RGB workflow with dedicated B&W inks are the only way to get to
the evenness the purists are going to demand.  On the other hand, I have no
doubt that the vast majority of B&W printers will use one of the easier
approaches that use color inks and OEM drivers.

Paul
www.PaulRoark.com

Thanks Paul. Just bought a bottle of EZW ink. Will give this a go and 
let you know what I think. 

Regards Peter.