QTR-Quadtone RIP

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

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
> 
> 
> 
> 
> 
> 
> Yahoo! Groups Links
> 
> 
> 
> 
>

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

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
> 
> 
> 
> 
> 
> 
> 
> 
> 
> Yahoo! Groups Links
> 
> 
> 
> 
>

Tom,

WOW, thanks indeed for the pointers, I'll get to work straight away 
and try to get excel doing what you say.

I'm not familiar with Roy's utility (being quite new to QTR) is 
there a link available?

regards, Jamie



--- 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


 
> > -----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

> 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?

Which stepwedge are you using when you print?

Are you starting the meaurements from the white patch, and ending white the
black?

Could you post the readings that you are trying to put into QTR?

--
Daniel Staver
http://daniel.staver.no

Jamie Creed wrote:

> > 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?

----------------------------------------------------------------
> Which stepwedge are you using when you print?
> 
> Are you starting the meaurements from the white patch, and ending 
white the
> black?
> 
> Could you post the readings that you are trying to put into QTR?
> 
> 
> Daniel Staver
> http://daniel.staver.no

Daniel

----------------------------------------------------------------

I'm using the 21step file from the QTR image select menu, and am not 
forgeting the white patch (good poiny.)

Here are the readings which wouldn't work:

0.04  0.08  0.13  0.19  0.24  0.30  0.36  0.42  0.48  0.54  0.62  
0.70  0.77  0.87  0.96  1.06  1.17  1.29  1.43  1.55  1.72

I must say Tom Moore has just posted some great pointers concerning 
this which have brought me instant success.

I'm new to this curve building game and appreciate your reply,

Jamie Creed