Digital BW, The Print

Hi Denis,

>I print on a brand new Epson R1800 loaded with 3 Eboni MK 
>and cleaning fluid in the 5 remain color positions on 
>Epson EEM and get horizontal banding in the midtones. 
>QTR, 2880, uni-directional, ordered.

...
>I did notice that I do not get banding when printing 
>on Hahnemuhle Museum Etching 350gsm.

>I am wondering if this banding is simply just an 
>ink/paper combination. 

>I am assuming that OEM color inks might have a 
>dot gain that is a little larger than MIS Eboni. 
>Thus the OEM color prints
>"hide" the banding with a bit of ink spread?

...

>I did another test print on EEM
>using the MIS ALPHA curve.
>Strangely NO banding appears.

I agree with Carl with respect to both different channels being of different
qualities and paper transport being a suspect.  Others have also noted that
different 1800s are of different quality.

I also agree with your analysis that the Eboni dot gain is so little
compared to the OEM inks that it probably does not hide the defects as well.
(While it may not be the same, I've noticed on draw-down tests that the
Epson inks spread more than the MIS inks.)  And, I think different paper
coatings affect this.

I have found some banding at the top and bottom edges of 8x10 prints with my
1800.  My conclusion was that the paper transport is so critical with this
setup that it does best when both rollers are engaged.  So, I print more
like 9 x 7 on letter size printers.

I've also heard some comments that the 1800 3-MK approach seems to show
image file defects more.  I had an example of that yesterday.  I'd taken
some cloud shots with my Canon Rebel XT and saw what appeared to be
horizontal and vertical microbanding in the 3-MK print.  I tried the R260
with a full B&W inkset, and the visibility of the artifacts was less, but
they were there.  On examining the file at 100%, the artifacts were
definitely in the file.  The inkset with dilute inks just did not show them
as clearly, perhaps due to the dilute inks spreading more and hiding the
very fine details of the file.



>Apart from that the prints are AMAZING. Compared to 
>Piezography NK7, they appear more neutral (and perfectly 
>warmer) to me, more sharp (dot grain seems to add 
>perceive sharpness), more luminous and much better
>linearized when testing using circular gradients.

The R260 inkset that is about to be released with allow -- with QTR -- that
system to have a black only approach that is not quite as good as the 1800
3-MK, but still very good given how easy and cheap it is.  Oddly, multiple
channels of MK do not improve the 260, but a single channel on the 260 has
significantly less microbanding than a single 1800 channel -- but with a
bit more graininess.  

I've made some PKNs for the 260 RC inkset -- 2 levels of toning -- that make
very nice glossy prints.  The 260 will also have a full B&W inkset for
extremely smooth prints -- again with 2 levels of toning in addition to warm
carbon.  It'll be interesting to see how many go with the full inkset or
just use the BO approach with color inks installed.  

I might add that I expect the 260 inkset ("UT-RC" [R series printers with
Claria inks]) to run in the 1800 with QTR.  One or more PKN channels for the
FB glossy types of papers might be something I'll do with the extra channels
in my 1800. 

Paul
www.PaulRoark.com