QTR-Quadtone RIP

--- In QuadtoneRIP@yahoogroups.com, Howard Shaw <glassman@...> wrote:
> I'm still not clear why you have rejected the "take existing curve for 
> similar paper/adjust ink limit at print time (if necessary)/make
> ICC for new paper" method that Roy suggested. It sounds a lot simpler.
 
Perhaps because I misunderstood something.  I didn't quite understand
Roy's comment at the time.  I thought that you had to extract the
underlying curve shape and input it into the curve editor in order to
be able to set limits.  Reading again I understand.  Thanks.

Question - how do I judge the ink limit setting in the print dialog? 
Is this measured in the same units as ink limits in the curve creator?
 I.e. so that -10 is like 90 in the curve creator, or is it entirely
suck it and see?

It's a neat solution, assuming that I can select a sufficiently
similar paper.  I'll probably use it for VFA.  The basic shape of
Cone's curves don't seem to vary all *that* much, so I am hoping that
the linearisation works well enough.

However I am not so optimistic about using this technique for
EpEnhMatte.  The shape of the black in Cone's curve is quite different
(lower) from his other curves and I'm already having trouble with ink
overloading.  I suspect that I'll need to be able to specifically
tweak the black.  For this paper I may attempt to simulate his curves
in the curve editor.

> > Perhaps another way of asking this question is whether the individual
> > curves that you enter for each ink are absolute or relative curves? 
> 
> You just need to use lower ink limits with 2880dpi, probably in the 
> region of 35-60% lower.

This might prove to be irrelevant, but I there's something I still
don't understand, and I can't seem to describe it properly.  If I
enter a set of curves for an ink in the curve creator, either through
an AVC or by points, how do I know how to scale those curves?  I could
extract the shape of the curves from the .quad, reduce them to 50
points, but I've got to scale them somehow.  If I scale them too low,
adjusting the limits isn't going to help me, as I can't use a limit
more than 100, can I?
 
> > (i)  Are there any software or Excel tricks for taking two columns of
> > data and producing the "xx.xxx;yy.yyy" pair that are required for
> > entering points in QTR?  And conversely, i.e. for taking the pairs and
> > producing columns in a spreadsheet?

Again, I had difficulty stating my question clearly.  I wanted to take
the points from the curve creator and paste them into Excel and
manipulate the curves.  Then turn them back into points and past them
into the curve creator.  I've worked out how to split the two numbers
separated by a ";" into two separate cells and how to recombine them
using a simple formula.

Thanks for your patience.

Ferdinand