QTR-Quadtone RIP

Tim

I see John Moody has provided the formulas you're looking for. My
implementation is different (mines a VBA function that can be used in a
spreadsheet) but both implementations give the same result to 14 decimal
places, except for the discontinuity area when we agree to "only" five
decimal points :-).

I updated my spreadsheet to include LAB density curves down for dmax down to
1.35. If you want a copy rather than making your own, email me and I'll send
it back.

Tom

> -----Original Message-----
> From: QuadtoneRIP@yahoogroups.com [mailto:QuadtoneRIP@yahoogroups.com] On
> Behalf Of timlbatten
> Sent: Monday, August 29, 2005 3:08 PM
> To: QuadtoneRIP@yahoogroups.com
> Subject: [QuadtoneRIP] Re: Curve building?/Spreadsheet
> 
> --- In QuadtoneRIP@yahoogroups.com, "Tom Moore" <r.t.moore@r...> wrote:
> > 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
> 
> Hi Tom
> 
> What is the formula to convert dMax to *L? -or- can you share the
> spreadsheet.
> 
> Also, does anyone know if there is an "Ideal Densities for Various
> DMax" chart available that goes as los as dMax 140. I have some not so
> great matte paper that maxes out at 142 on my UC 7600.
> 
> Thanks!!
> tim
> 
> 
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> 
> Yahoo! Groups Links
> 
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