QTR-Quadtone RIP

Josh,

You might be a tad picky, but only a tad. Notice that the ink 
separation page prints in 5% steps, yet you are linearizing in 2%. 
Nothing wrong in that per-se, but you are more likely to find 
anomalies.

The true pure K limit may be somewhere between 75 and 80%. QTR 
proabaly lays down some LK ink down to 98% patch and that may be 
interacting with the maximum K the paper is capable of handling.

So I would set the K limit to 75%, and leave the K boost empty. Or 
else, K limit=70, K Boost=75. If this solves the 98-100 reversal, 
you should be good to go. To eke out the last ounce of Dmax may 
require some interations. I personally don't get too bothered by 
1.65 versus 1.62 densities.

Tell us how it goes.

Shilesh

--- In QuadtoneRIP@yahoogroups.com, "joshhackney" <joshhackney@g...> 
wrote:
>
> I'm having difficulty achieving the Dmax that I think the 
following ink/paper combination 
> should be able to achieve:
> 
> 7800, K3, Innova PSC.
> 
> When printing the ink separation page, the K values where as 
follows
> 
> 65.00	17.93
> 70.00	17.89
> 75.00	17.41
> 80.00	17.15
> 85.00	17.20
> 90.00	17.59
> 95.00	17.36
> 100.00	17.53
> 
> Therefore, I have set the K ink limit to 75 and black boost to 
80.  No matter what I try, I 
> can't get anything close to 17.15 when printing the 51 step random 
target with the non-
> linearized curve I have created.  I'm also getting reversals on 
the 100%K patch.  The 
> following is the end of the data produced by QTR-Linearize-
Data.app.  
> 
> 90.00	1.589	18.26	0.82	2.00	-         
L                   |  a    b                     +
> 92.00	1.596	18.07	0.81	2.13	-         
L                   |  a    b                     +
> 94.00	1.599	18.01	0.79	2.17	-         
L                   |  a    b                     +
> 96.00	1.603	17.89	0.84	2.13	-         
L                   |  a    b                     +
> 98.00	1.605	17.83	0.76	2.40	-         
L                   |  a     b                    +
> 100.00	1.594	18.13	0.71	2.50	-         
L                   | a       b                   +
> 
> Even the 98.00 patch is at 17.83 - a far cry from 17.15 . . . or 
am I being too picky?  It 
> seems that with the K ink limit of 75 and boost of 80, that the 
100 patch generated with 
> the curve should be the same as the 80 patch on the ink separation 
page, or am I missing 
> something? 
> 
> Thanks for any insight you can provide.
> 
> Best.
> 
> Josh
>