Digital BW, The Print

Hello,

I remember reading an email from Paul Roark mentioning that the 3MK
approach was built with the idea that the conversion would still allow
full MK color printing. And that the process could be a little bit
smoother having another MK channel firing. 

Paul said optimal would be like 3.5...

Anyone also heard about this or experimented with more than 3MK channels?

Paul if you can find the time, could you develop more on the 3 and a
half MK? :-)

Or could a diluted Eboni 4th MK channel would help? Like the toning
color channels one can find in the QTR 3MK curves?

Thanks all,

Denis Bouchard

>... the 3MK approach was built with the idea that the 
> conversion would still allow full MK color printing. 

> And that the process could be a little bit
> smoother having another MK channel firing.

I've only heard of a few samples that needed the 4th channel.  For most 
the difference between 3 and 4 is not worth dealing with.

 
> ... could a diluted Eboni 4th MK channel would help? 

It would be warmer than teh 100% Eboni.  But, a dilute gray could 
definitely add to smoothness.  For most of my shots, the 3MK is just 
fine, however.

Paul
www.PaulRoark.com

Paul, I aligned the heads once again, nozzle check is perfect.

Printed 6x9 images centered on 11x14 Polar Matte (with the PA BW curve
which is perfect for it). So micro banding near the top and bottom
edges should not be an issue. And I get micro banding.

So I can safely assume my R1800 sample is one of the few that would
benefit from a 4th channel.

How would one go about using a 4th channel?

I'd really appreciate your advice on this and I am sure others in my
situation could benefit too.

Many thanks for your contribution to this community.

Denis

> > And that the process could be a little bit
> > smoother having another MK channel firing.
> 
> I've only heard of a few samples that needed the 4th channel.  For most 
> the difference between 3 and 4 is not worth dealing with.
> 


>

>... my R1800 sample is one of the few that would
> benefit from a 4th channel.
> 
> How would one go about using a 4th channel?

I think there is at least one list member who might have made some 4-
MK curves.  Unfortunately, no longer have the ones I experimented 
with.

I'd first see if there are channels that print smoother than others 
by putting the carts in different locations and printing 21-step test 
strips with each of the channels independent of the others.  It may 
be that you'll find there are some that are quite good and, when they 
are used as the 3 channels, are enough.

After finding the best 3, if there is still microbanding, I'd focus 
on where it is in the 21-step test prints and start the fourth MK a 
little before that, reducing the other three from that point on by 
1/3 the amount of the new channel's values.  This will have to be 
polished and linearized, but I think this basic approach will get you 
there.

Hope this helps.

Paul
www.PaulRoark.com

I am happy to report that after testing every single channel with the
21 steps file using custom curves in QTR that Paul Roark was right
(again? ;-) ).

I was surprised to notice that the worst channels in my R1800 where
MK, K and GL. Then C. The best where Y and M followed closely by R and B.

So I am now using 3MK with these channels: Y, M and R.

I assigned the largest values covering curve to the Y channel. Then
the 2nd one to M and third to R.

It prints... amazingly better! No more micro banding and seems overall
a bit smoother too.

I imagine R1800 sample variations do exist and that those who are
having issues with their current channels selection might benefit from
this channel testing and swapping.

Thanks Paul!

Denis


--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "pr_roark"
<pr_roark@...> wrote:

...
> I'd first see if there are channels that print smoother than others 
> by putting the carts in different locations and printing 21-step test 
> strips with each of the channels independent of the others.  It may 
> be that you'll find there are some that are quite good and, when they 
> are used as the 3 channels, are enough.

...

> 
> Paul
> www.PaulRoark.com
>