Digital BW, The Print

Olivier,

I mistakenly thought the Piezo inkset you were using was a matte 
version.  I missed the fact that Jon had released the glossy MPS 
inkset.  So, some of my answers need clarification.  Sorry for the 
confusion.


> > We're using Glop (the MIS version ... both in the first pass and 
> > as a second-pass overcoat.

With a glossy set, you might be fine with a single pass.  With a 
matte inkset like the 1800 3-MK, the second pass is needed.

In the 3-MK glossy workflow, the second pass is a solid, even over-
coat of Glop that covers an image area larger than the printed 
image.  As such there are no registration problems.  It's just like a 
liquid laminate.

 
 
> ... I use Piezo MPS. For some reasons, 
> I "feel" K is different from the other inks, but overall it's a 
> glossy set.

I have no experience with that particular inkset.  

The results Carl and I have been experimenting with is a matte inkset 
that would be more similar to the older Piezo matte inksets.


> > With a K6 [matte inkset] setup,  
> > you'd have to ... substitute a PK ...

> > In my latest QTR profile, the Glop curve is as follows: 0;0	25;5
> > 	50;10	75;24	80;27	85;30	90;30	92.5;27	95;22	100;0


With a matte inkset one needs a lot of Glop overcoat to equalize the 
gloss across the grayscale evenly.  

With a glossy underlying set, the uses of an overcoat would include 
different factors.  If there is any bronzing or gloss differential, 
however, the Glop might still help, and you'd probably be able to 
kick the dmax up.  Weighing whether it'd be worth it would be very 
different than for a matte inkset, where it's really necessary.



> > My PK curve is as follows: 0;0	10;1	20;1.5	30;1.5	
> >     40;2     50;1.5
> > 	60;1.5	65;2	70;1.5	75;1	80;4.25	85;8	90;15
> > 	92.5;22	95;35	98;60	100;100	  (Ink limit 100)


I believe that with the overcoat of Glop we can usually put down a 
higher load of black pigment than we could without the overcoat.

 
> > In general, I think it's a mistake to have any 
> > other inks in the 100% spot 

> Do you care to expand on this.

My experience with matte paper was that If I just measure the 100% 
spot, I find the 100% Eboni and no other ink beats any combination of 
Eboni with another lighter or color ink.


With a glossy papers I have found that the addition of "blue" (cyan 
plus magenta or R800 blue in various ratios) pigment ink often raises 
the dmax.  In fact, I'm more inclined to not care about a bit of blue 
in the PK for dmax purposes.  The tone shifts at that low level would 
be insignificant, and the density drop will not cause any 
posterization.  And there may be situations where just filling in for 
another ink helps no matter if it is a somewhat lower load ink.

> > The second pass is done with a 100% Glop overcoat, 
> > split between 2 channels.  
> > With the 1800 I was able to see some microbanding in the 
> > glop if only one channel was used.  
> > That would probably not happen in a 3.5 pl printer.


> Why not go the PrintShield route ...

The printer-applied spray with Glop is easier.

I hope this clarifies any confusion I may have causes.

Paul         
www.PaulRoark.com