QTR-Quadtone RIP

Hi -

I'm working will all grey inks and want to use black ONLY for the densest of the dense...

I don't see any discussion of the BOOST_K= variable and am trying to get a good 
calibration but with denser blacks - I'm hoping that this variable holds the key.

If I set the black ink limits to 100 then I get a denser black but the calibration procedure 
seems to rely on having the ink limit set to the "paper coverage" point. I don't want to get 
a dull, lifeless black, I want to get a very dense black.

if I set the ink limit to 100 then the black percentages used in the calibration process 
seem to get very weird (they all come in at less than 50% - going down to less than 1%)

So, how do I get all the tonal range that is provided by a quad-black ink, but still get a full 
dense black with 100% or more ink covereage at 0,0,0?

Any suggestions?

Tom Stratton

With BOOST_K the darkest ink (usually K) increases towards the ink limit,
but at the end you get a sudden increase towards whatever value you set fopr
BOOST_K. Let's say your ink limit is 60 and BOOST_K is 100. The the black
will increase towards 60, and then just before reaching that point it will
suddenly increase and end up with an ink limit of 100.

BOOST_K sometimes works well, but not always. Particularly on glossy papers
I've noticed that a big difference between BOOST K and ink limit can cause
an abrupt transition to black in the shadows. In those cases I've found it
far better to just set the ink limit to 100 and controlling the shape of the
curve with the shadow, highlight and gamma settings before linearizing.

Also make sure OVERLAP is set to 0 if you want only black in the blacks.
Otherwise some of the next darkest ink is going to mix into the black by
whatever value you specify.

--
Daniel Staver
http://daniel.staver.no 

> I'm working will all grey inks and want to use black ONLY for 
> the densest of the dense...
> 
> I don't see any discussion of the BOOST_K= variable and am 
> trying to get a good calibration but with denser blacks - I'm 
> hoping that this variable holds the key.
> 
> If I set the black ink limits to 100 then I get a denser 
> black but the calibration procedure seems to rely on having 
> the ink limit set to the "paper coverage" point. I don't want 
> to get a dull, lifeless black, I want to get a very dense black.
> 
> if I set the ink limit to 100 then the black percentages used 
> in the calibration process seem to get very weird (they all 
> come in at less than 50% - going down to less than 1%)
> 
> So, how do I get all the tonal range that is provided by a 
> quad-black ink, but still get a full dense black with 100% or 
> more ink covereage at 0,0,0?
> 
> Any suggestions?