QTR-Quadtone RIP

I'm trying to figure out by myself how this works :-( 

Well I compared my values with values for other curves (those provided) and they do look different, i could blame my cheap scanner but really don't know.  Any idea?

Now I made some experimenting. If I change the value 54 (step 15) in the array for just 55, then it works.

My values: 95 94 93 91 90 88 86 84 82 80 77 74 72 64 54 46 37 25 16 6 1

The curves are still ugly, kind of "knee" in the middle, as compared with  the pretty ones provided by QTR (that is another problem), but I wondered how come that a slight change in ONE value makes the difference between "valid" and "invalid".

Help, hints, comments,  would be appreciated :-)









________________________________

From: rabanito <rabsanito@...>
To: QuadtoneRIP@yahoogroups.com
Sent: Tuesday, January 27, 2009 10:18:00 PM
Subject: [QuadtoneRIP] Linearization Fails


I'm trying to create a curve using my flatbed scanner. I did
everything as instructed, I think :-)

When at least I put the L values in the linearization array:

95 94 93 91 90 88 86 84 82 80 77 74 72 64 54 46 37 25 16 6 1

I click "show curve" and get "invalid linearize curve - not constantly
increasing"

Thanks for any help

    


      

[Non-text portions of this message have been removed]

I don't know the details of the algorithm, but indeed the 
linearization sometimes fails if the curve is too far of a linear one 
and some numbers are too close together. This seems the be case in 
our data. Frankly, expecially the first three-five numbers seem too 
close together. The best approach is to work a bit more on the non-
linearized curve. This gives much better control anyhow.

Joost

--- In QuadtoneRIP@yahoogroups.com, jorge caruso <rabsanito@...> 
wrote:
>
> I'm trying to figure out by myself how this works :-( 
> 
> Well I compared my values with values for other curves (those 
provided) and they do look different, i could blame my cheap scanner 
but really don't know.  Any idea?
> 
> Now I made some experimenting. If I change the value 54 (step 15) 
in the array for just 55, then it works.
> 
> My values: 95 94 93 91 90 88 86 84 82 80 77 74 72 64 54 46 37 25 16 
6 1
> 
> The curves are still ugly, kind of "knee" in the middle, as 
compared with  the pretty ones provided by QTR (that is another 
problem), but I wondered how come that a slight change in ONE value 
makes the difference between "valid" and "invalid".
> 
> Help, hints, comments,  would be appreciated :-)
> 
> 
> 
> 
> 
> 
> 
> 
> 
> ________________________________
> From: rabanito <rabsanito@...>
> To: QuadtoneRIP@yahoogroups.com
> Sent: Tuesday, January 27, 2009 10:18:00 PM
> Subject: [QuadtoneRIP] Linearization Fails
> 
> 
> I'm trying to create a curve using my flatbed scanner. I did
> everything as instructed, I think :-)
> 
> When at least I put the L values in the linearization array:
> 
> 95 94 93 91 90 88 86 84 82 80 77 74 72 64 54 46 37 25 16 6 1
> 
> I click "show curve" and get "invalid linearize curve - not 
constantly

> increasing"
> 
> Thanks for any help
> 
>     
> 
> 
>       
> 
> [Non-text portions of this message have been removed]
>