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QTR-Quadtone RIP

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linearization problems

linearization problems

2014-04-06 by Jacques Caron

Hi

On a Mac, with QTR and a Epson 1430 with Eb6 config. I managed to create or redo some exiting curves. I got one that's nearly perfect (except for some bumps in the dark end).

After reading the patches (51 steps) I exported the text file. When I want to linearize the file, the script tells me that the Lab values are not in order (they are). I know that minor changes in the lab values can stop the script.

My question, can I copy this text file, change the numbers by hand (lab values) save the new file and make a quad file?

Many thanks

Jacques Caron

Re: [QuadtoneRIP] linearization problems

2014-04-06 by Roy Harrington

Sure you can edit the .txt file. If you see values that seem off just tweak them a little.
Actually I think 51 steps is too many for most situations. I'd use the 21step and even
better is to use the 21x4 where you get an average of 4 values for each step level.

Roy

Show quoted textHide quoted text
On Sun, Apr 6, 2014 at 6:48 AM, Jacques Caron <jacques.caron@...> wrote:


Hi

On a Mac, with QTR and a Epson 1430 with Eb6 config. I managed to create or redo some exiting curves. I got one that's nearly perfect (except for some bumps in the dark end).

After reading the patches (51 steps) I exported the text file. When I want to linearize the file, the script tells me that the Lab values are not in order (they are). I know that minor changes in the lab values can stop the script.

My question, can I copy this text file, change the numbers by hand (lab values) save the new file and make a quad file?

Many thanks

Jacques Caron
Photographe
jacques.caron@...








--
Roy Harrington
roy@...
www.harrington.com

Re: [QuadtoneRIP] linearization problems

2014-04-07 by Jacques Caron

Many thanks

I'll redo my test prints with the 21x4 (although I'm reading my samples three times to see if everything is OK).

Thanks again

Le 2014-04-06 à 14:21, Roy Harrington <roy@harrington.com> a écrit :



Sure you can edit the .txt file. If you see values that seem off just tweak them a little.
Actually I think 51 steps is too many for most situations. I'd use the 21step and even
better is to use the 21x4 where you get an average of 4 values for each step level.

Roy



On Sun, Apr 6, 2014 at 6:48 AM, Jacques Caron <jacques.caron@...> wrote:


Hi

On a Mac, with QTR and a Epson 1430 with Eb6 config. I managed to create or redo some exiting curves. I got one that's nearly perfect (except for some bumps in the dark end).

After reading the patches (51 steps) I exported the text file. When I want to linearize the file, the script tells me that the Lab values are not in order (they are). I know that minor changes in the lab values can stop the script.

My question, can I copy this text file, change the numbers by hand (lab values) save the new file and make a quad file?

Many thanks

Jacques Caron






--
Roy Harrington
roy@...
www.harrington.com



Jacques Caron

Re: linearization problems

2014-04-07 by Joseph Fammartino

Roy
I am having the same issue with Lab values not linear. I did what you suggested and tweak them in order. Saved the.txt, when I when I put it in QTR linearize it gives the same non linear Lab values even though they are corrected. What should I do with the .txt file?
Joe Fammartino
Jfammartino@gmail.com

Sent from my iPhone

Re: [QuadtoneRIP] Re: linearization problems

2014-04-07 by Roy Harrington

The values are connected with a "smooth" curve. If the variations are too rough you
get swings that are too big (think Curves in Photoshop). The pre-linearized values have
to be good enough. Either tweak the values a little or adjust the curve for a better
approximation.

Reading the values into a spread-sheet and graphing them tends to show what's happening.

Roy
Show quoted textHide quoted text
On Mon, Apr 7, 2014 at 7:32 AM, Joseph Fammartino <jfammartino@...> wrote:
Roy
I am having the same issue with Lab values not linear. I did what you suggested and tweak them in order. Saved the.txt, when I when I put it in QTR linearize it gives the same non linear Lab values even though they are corrected. What should I do with the .txt file?
Joe Fammartino
Jfammartino@gmail.com

Sent from my iPhone

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