QTR-Quadtone RIP

Tyler,

> Mike, you are up to some very cool things, really impressive. Very
> interested in hearing about the ink.
>
I like it more than I expected. Paul Roark has done all the hard work, I am
just standing on his shoulders. Works great in R1900. I am using18% Eboni as
toner in 3/4 tones.

> I think I know what you mean regarding my question... I'd import a
> different toner curve based on tests, which requires another start
> linearization, and then the proportion of toner to grays in various tonal
> areas has changed from that which I had used to base the curve edit upon...
> round and round. That's ok, I accept that for this particular project, if
> I'm getting the picture.
>
Yes that's exactly the issue, round and round we go and there is no way to
predict the outcome, though you can guesstimate better after the first
linearization.

>  Let us know how your work goes, really intriguing. Can you overlap
> progressively less moving down to the low end? So you have K only at 100%?
> Everything get's a bit jammed up down there and it's hard to control...
>
I am not sure,  I think not for maximum smoothness. So I may just generate
two curve sets one for maximum smoothness based on Cone style overlapping
ink curves and one for maximum dmax based on QTR curves.

Mike

>
> Tyler
>
>
> --- In QuadtoneRIP@yahoogroups.com <QuadtoneRIP%40yahoogroups.com>,
> Michael King <drmrking@...> wrote:
> >
> > Hi Tyler,
> >
> > I think the answer to your question is yes, but ...
> >
> > Having experimented over the last few months with HP-C6 aiming for
> neutral
> > and needing to warm it up in the 3/4 tones to achieve that, I got very
> > frustrated with the inflexibility of QTR to re-linearise after editing a
> > toning curve.
> >
> > The problem is that you can add a toner as you describe below, but when
> you
> > linearise the tone curve will change and you can't edit it further, you
> can
> > only start again with a new tone curve. There is no way, I can see, to do
> > sequential linearizations in QTR and that's a real pain.
> >
> > My solution was to write my own linearization program that takes a set of
> > QTR curves (actual ink values in Quad file) and linerarizes them. This
> let's
> > me edit a toner curve ink values (often manually in Excel) and
> relinearize
> > them again. It even allows me to look at the predicted re-linearized ab
> > curves before I print them and decide if I need to tweak them further.
> >
> > Through testing this HP-C6 approach I also discovered that the QTR curve
> > model that doesn't use many overlapping inks, is suspectable to
> > posterization. I had a print that posterized and someone suggested is was
> > possibly a problem with QTR curve model.
> > So I created another curve model that was more like Cone's model where
> the
> > inks overlap much more and indeed the posterization problem was solved.
> BUT
> > the cost of this overlapping ink approach is reduced dmax. On Canon Rag
> 310
> > the dmax drops from L=15.3 to L=16 due to the other inks polluting the
> > darkest ink. So you've got to choose between the limitations of the two
> > approaches.
> >
> > Learn't a lot about QTR in the last few months.
> >
> > Mike
> >
> >
> >
> >
> > On 5 March 2010 23:06, tboleyyh <tyler@...> wrote:
> >
> > >
> > >
> > > after going through all the references I can find, it looks to me like
> the
> > > Photoshop curve import function in the Windows version with curve
> creation
> > > is the most straightforward, current, and viable approach to making
> unique
> > > toner setups..
> > > Would you QTR experts here agree?
> > > Thanks,
> > > Tyler
> > >
> > >
> > >
> >
> >
> > [Non-text portions of this message have been removed]
> >
>
>  
>


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