QTR-Quadtone RIP

Jamie

I see you have xrite's toolcrib and a densitometer. What I do, is print a
step wedge (I use the 21 step), and then measure the density of each step.
Using toolcrib, I pop the density readings into an excel spreadsheet that
displays the densities as a graph. I can see how the density of each step
increases over the 0% to 100% black range. It should be uniformly increasing
over the range (i.e. it should not decrease). I usually end up printing the
stepwedge several times as I adjust the Highlight, Shadow, and Gamma
parameters to bring the density curve nearer to linear. My spreadsheet is
set up to store and plot the density values from a number of runs as I
(hopefully) get closer to my final curve. Plotting several stepwedges lets
you see the effect of changing the parameters.

The spreadsheet also can compute L* values from density so I can use Roy's
utility to create an ICC profile of the final curve for previewing in
Photoshop.

Tom Moore

> -----Original Message-----
> From: QuadtoneRIP@yahoogroups.com [mailto:QuadtoneRIP@yahoogroups.com] On
> Behalf Of Jamie
> Sent: Sunday, August 28, 2005 12:30 PM
> To: QuadtoneRIP@yahoogroups.com
> Subject: [QuadtoneRIP] Re: Curve building?
> 
> Thank you Tom,
> 
> I don't really understand "if you plot your density curve prior to
> linearizing" could you elaborate. I've spent the last couple of days
> and nights absorbing you superb User Guide and feel i'm pretty close
> to getting the output I really want,
> 
> regards, Jamie
> 
> 
> --- In QuadtoneRIP@yahoogroups.com, "Tom Moore" <r.t.moore@r...>
> wrote:
> > Jamie
> >
> > You need to get your curve closer to linear by "hand" before you
> linearize. Roy will know the specific cause of your error message,
> but in general, if you plot your density curve prior to linearizing,
> it should be more or less uniformly increasing over the density
> range. If there are dips or large bumps in the grey or toner curves,
> use the Highlight, Shadow or Gamma values to smooth them out.  Once
> the curves are fairly smooth then use the Linearize to finish them.
> 
> > Tom Moore
> 
> 
> > > -----Original Message-----
> > > From: QuadtoneRIP@yahoogroups.com
> [mailto:QuadtoneRIP@yahoogroups.com] On
> > > Behalf Of Jamie
> > > Sent: Sunday, August 28, 2005 11:55 AM
> > > To: QuadtoneRIP@yahoogroups.com
> > > Subject: [QuadtoneRIP] Curve building?
> 
> while trying my hand at a little curve building, and then trying
> to linearise the curve, I keep getting an error "linearization
> failed - not constantly....."
> 
>  Anybody got any ideas?
> 
>  regards, Jamie
> 
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> 
> Yahoo! Groups Links
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