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.quad on mac

.quad on mac

2016-03-29 by sw3457@...

Hi -- Anyone know how to edit a .quad text file on a Mac to make changes to the curve? I get the workflow for a .qidf but the .quad is confusing and I can't find any documentation for adjusting it (even though the text file will open). Thanks in advance! Scott

Re: [QuadtoneRIP] .quad on mac

2016-03-29 by Douglas Taylor

Scott,
You can't edit the .quad file.
Edit the .txt file.
The quad file is created from the txt file.
Doug
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> On Mar 29, 2016, at 10:41 AM, sw3457@comcast.net [QuadtoneRIP] <QuadtoneRIP@yahoogroups.com> wrote:
> 
> Hi -- Anyone know how to edit a .quad text file on a Mac to make changes to the curve?  I get the workflow for a .qidf but the .quad is confusing and I can't find any documentation for adjusting it (even though the text file will open).    Thanks in advance!  Scott
> 
>

Re: [QuadtoneRIP] .quad on mac

2016-03-29 by simone

Actually you can. 

For each ink you find 256 entries in the file. 0 means no ink. 65535 means 100%. So if you edit directly the file by changing the numbers, it will work. I have done that to get the mix on inks that allowed me to get paper white and put the values on the curve creation tool to get a new curve. I think it is of little usefullness to actually edit the file by yourself, but you can.

simone personal website:
www.lookinglass.it
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> Il giorno 29 mar 2016, alle ore 16:41, sw3457@... [QuadtoneRIP] <QuadtoneRIP@yahoogroups.com> ha scritto:
> 
> Hi -- Anyone know how to edit a .quad text file on a Mac to make changes to the curve?  I get the workflow for a .qidf but the .quad is confusing and I can't find any documentation for adjusting it (even though the text file will open).    Thanks in advance!  Scott
> 
>

Re: .quad on mac

2016-03-29 by richard@...

How much (and what kind) of a change are you trying to make to the .quad file?

There really isn't any documentation on how to edit the quad curves (although a few people have developed their own methods for doing it—myself included). You can open the .quad file in any text editor, and then cut and paste from there. I wrote a post a long time ago about how to remap ink curves to different positions, but editing the shape of the curve is another story. Here is a link to that first post on the subject: Quad Tone Rip .quad Files
Quad Tone Rip .quad Files
And how to edit them without setting the house on fire. For those using Quad Tone Rip, you know that you need to first create an ink descriptor file, and install i...
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But like I said, I've done quite a bit of work figuring out how to open, correct, and export a new .quad file using spreadsheets. Roy has built a similar feature into the new version of QTR (2.7.6-2.7.7) that will relinearize the quad curves when dropping the original curve and a measurement file onto the linearize-quad app. My approach is different in that I can map the ink curves to any shape density curve I want (rather than just making a straight line), so it it more versatile and less error prone than the QTR version. The actual formulas are too involved to get into here, and it took me several months of testing and refining to get it to work the way I wanted. I do offer this as a service through my site if you are interested it just getting something working (if the QTR app doesn't do what you want).


Hope that helps,
Richard Boutwell


Re: [QuadtoneRIP] .quad on mac

2016-03-29 by simone

Sorry I replied in a hurry and it came out quite cryptic. What I wanted to say is that looking directly into the quad file (and eventually editing it) can be useful in some cases and it can be done. In my case I printed a digital negative of a grey 100-step chart and to avoid a lenghty process of repeated guessing of what should have been the minimal density able to produce paper white in the final print, I put the quad values in an excel spreadsheet. Just as an example, if you know that your 75th step is already white, what you do not know (if not by a gross aprroximation given by the curve view tool) is the exact mix of inks put down by the printer at that specific point of the curve. That is where looking in the .quad file is very handy. Each color has 256 levels and fpr each level a number ranging from 0 to 65535 tells you how much of that specific ink is layed down by the printer. Just dividebthat number by 65535 and you have the % for each ink. In my case, those numbers became the new ink limits in the refined curve to get the smoothest possible gradient .
Hope that helps

simone personal website:
www.lookinglass.it
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> Il giorno 29 mar 2016, alle ore 16:41, sw3457@... [QuadtoneRIP] <QuadtoneRIP@yahoogroups.com> ha scritto:
> 
> Hi -- Anyone know how to edit a .quad text file on a Mac to make changes to the curve?  I get the workflow for a .qidf but the .quad is confusing and I can't find any documentation for adjusting it (even though the text file will open).    Thanks in advance!  Scott
> 
>

Re: [QuadtoneRIP] .quad on mac

2016-03-30 by sw3457@...

Thanks Simone. Now I understand what the numbers refer to and I can see how they represent the curves displayed in Curve View. So, each row for each ink in Excel refers to the same point on the X-axis in Curve View -- in other words the 256th row of each ink in Excel represents the 100% patch on the step wedge? That makes sense, and thanks for the explanation.

Re: [QuadtoneRIP] .quad on mac

2016-03-30 by Simone Simoncini

yes, that's correct. it's like the X axis on the curve view is divided into 256 levels. the last one is the amount of ink laid out at 100%. 65535 tells the printer to output 100% of that particular ink.
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On Wed, Mar 30, 2016 at 2:01 AM, sw3457@comcast.net [QuadtoneRIP] <QuadtoneRIP@yahoogroups.com> wrote:

Thanks Simone. Now I understand what the numbers refer to and I can see how they represent the curves displayed in Curve View. So, each row for each ink in Excel refers to the same point on the X-axis in Curve View -- in other words the 256th row of each ink in Excel represents the 100% patch on the step wedge? That makes sense, and thanks for the explanation.


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