QTR-Quadtone RIP

Sure I'll do some tests with the bullseye.
I am checking the smoothness of the linearity and I didn't see any flat
spots.
More on this after some testing. But also its a tough image to print.
As I said I'll upload the section that tends to posterize for people to test
if they want.

Mike

On 30 March 2010 00:36, Roy Harrington <roy@...> wrote:

>
>
> I think Shilesh has a valid point. With the standard QTR transitions when
> you use more inks the slope of the transitions are steeper since there are
> more up and downs. With just 3 grays the transitions are naturally wider.
> Graph Piezo K7 curves and QTR UCk3 curves and note that the slopes a pretty
> comparable. What all this means is that you need to be more accurate
> in the relative density measurements with K7 inks and QTR curves.
> (I take it you are creating your own curves with K7 inks using QTR curves).
>
> I must admit I haven't made many K7 curves since Cone provides them,
> but like Shilesh says with K3 inks I've never had issue with smoothness.
> What I think you are calling posterization is actually flat spots in a what
> should be a smooth gradient.
>
> In the new release I've included a bullseye.tif pattern in the Eye-One
> folder.
> Print that out with your setup. This shows anomalies very easily in the top
> half. Then the bottom half makes it easy to see where the issue is.
> With a graph of the curves you can see which inks are in transition at that
> point. If its a flat spot the lighter ink is marked lighter that it really
> is.
>
> Roy
>
>
> On Mon, Mar 29, 2010 at 4:07 PM, Michael King <drmrking@...<drmrking%40gmail.com>>
> wrote:
> > Hi Shilesh,
> >
> >> I must say I have never ecountered posterization issues with customary
> inks
> >> that use K, LK, and LLK alone, or as backbone followed by LM, LC, and
> others
> >> for toning via use of "toner" or "copy curve from" in QTR ink setup.
> >>
> > Tomorrow I'll upload the section of the image that tends to posterise and
> > you can try for yourself :)
> > I'll email when its done. You might be surprised....
> >
> >>
> >> I think Cone type overlap may (perhaps) be required when using 4+ gray
> >> inks, which in my opinion is at best an overkill, and technical mas@
> #$%^tion
> >> at worst. I have not seen a print that was better simply because it had
> 6 or
> >> 7 shades of gray. Try to reduce the number of gray inks in your set up,
> and
> >> use standard QTR curves design tools. I am curious what your eyes will
> see.
> >>
> > I don't think there's a particular reason why more overlap is required
> with
> > more inks, but maybe as the ink curves bunch more together. I think its
> more
> > about smoothing the tonal change in the inks sets, especially the splits.
> >
> > But the one place that overlap is required with some papers is at dmax.
> Some
> > papers require both #1 and #2 ink densities to reach dmax, maybe 30 on
> the
> > QTR graph scale for #2 ink, Canson Photorag is such a paper. With #1 ink
> > only you achieve at best approx L= 1.0 less. On the other hand on other
> > papers such as Epson Hot Press Bright, dmax can be achieved easiest
> without
> > any #2 ink @ dmax.
> >
> > Mike
> >
> >
> > [Non-text portions of this message have been removed]
> >
> >
> >
> > ------------------------------------
> >
> > Yahoo! Groups Links
> >
> >
> >
> >
>
>  
>


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