QTR Curve Question

Although I have been getting some decent results creating digital negatives (cyano and Kallitype) by using the B&S curves and judicious/iterative use of the Epson 3880 ABW controls ( color density, contrast, brightness, etc), I have made the plunge into Quadtone RIP world. After playing with the program for a day and reading about how it works - I can see it is a clever program and how it can improve your digital negative quality. I also made some really nice toned B&W prints that were quite striking!

However since I am starting from zero ( or perhaps less than zero), is there a repository of "starting" curves for the various process ( and possibly paper combinations) to begin the iterative improvement to your curves. I found the Yahoo quadtone group, but not much there - as I understand you need a .qidf and .acv file to start. Can anyone point me in the right direction of such a set of curves. Of course if anyone would like to "lend" me their curves for cyanotype and Kallitype using the Epson 3880/K3 inkset I would be grateful for a starting point.

Dave Najewicz

There is a Pt/Pd .qidf/.acv set for 3800 in the file section of the QTR group.io forum. It may work for kallitype as a starting point (I don't know how different 3800 is from 3880, though.)

On the other hand if you want to go first class, get Richard Boutwell's QCDN program that will handhold the whole process for you. (disclaimer: I have never used it.)

:Niranjan.

nmp said:

There is a Pt/Pd .qidf/.acv set for 3800 in the file section of the QTR group.io forum. It may work for kallitype as a starting point (I don't know how different 3800 is from 3880, though.)

On the other hand if you want to go first class, get Richard Boutwell's QCDN program that will handhold the whole process for you. (disclaimer: I have never used it.)

:Niranjan.

Click to expand...

I use Richard's QCDN software, and it makes easy work of calibrating several different alt processes. Disclaimer: I use it only for pt/pd.

Alan9940 said:

I use Richard's QCDN software, and it makes easy work of calibrating several different alt processes. Disclaimer: I use it only for pt/pd.

Click to expand...

I use QCDN as well, for kallitypes — it makes the process a lot simpler. Dave, If you are still attending Clay Harmon’s photogravure workshop this weekend, you will see it in action there — Clay swears by it.

Thanks to all for your timely/helpful responses.

Niranjan - I will look at the Pt/Pd curves for the 3800, it uses the same inkset at the 3880, apparently the 3880 has improved "dithering" and other minor change from the 3800 but otherwise identical, so the difference should be minimal. I will probably try the curves to see if I like them and use as a starting point. I had been using a the B&S Pt/Pl .acv curve with PS and as I said getting fairly good results, so this makes sense. Basically I just want to learn the "mechanics" of using QTR to see how it works before taking Clay Harmon's photogravure course.

There seems to be unanimity regarding the QCDN, which is good because it must be a excellent solution if all of you talented alt-photo printers are using it. I will definitely look into getting it after the course.

Sanders - as I noted I will be at Clay's course but the second one, Aug 5-6 .... I really look forward to learning the process.

My summer has been very busy with a lot of trips - last weekend I was in California - San Diego, visiting my brother - I was poking around the local area and went up to Escondido , and I happened into a Photography Gallery - "The Photographer's Eye", and to my amazement they were hosting an Alt Photography Show with some great work - if you ever get out that way check it out. Apparently there is an active alt photo community in the San Diego area. You may find the attached announcement interesting -

I think the 3880 also added the Vivid Magenta ink over the 3800’s older magenta ink. So it may make a difference if the curves use the magenta inks.

L Gebhardt said:

I think the 3880 also added the Vivid Magenta ink over the 3800’s older magenta ink. So it may make a difference if the curves use the magenta inks.

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Larry,

You are absolutely right - I did a quick count - both are 9 cartridge printers so I assumed....it should be a non issue for digital negs since all the information I have seen uses Pk, Lk, LLK and Y for digital negs that use UV light....

KYsailor said:

However since I am starting from zero ( or perhaps less than zero), is there a repository of "starting" curves for the various process ( and possibly paper combinations) to begin the iterative improvement to your curves.

Click to expand...

Why not do it 'right' and actually linearize your own process for your own materials, methods etc? QTR includes a linearization tool that can create a curve based on measurements of a test chart. You can scan the densities (the L value of a Lab* sample, taken in e.g. Photoshop or GIMP) of a test chart you print with your process (cyano, Van Dyke etc.) using a non-linearized QTR curve. These density values can then be used to create a linearization curve for your process, materials etc. It's a lot faster than iteratively 'tweaking' a curve, which moreover brings the risk of going round in circles (been there, done that...) It seems a little daunting or technical at first, but ultimately, it's a more efficient approach especially if you want to linearize several processes.

Thanks for the advice - that seems to be consensus that I need to just go off and do this.....

KYsailor said:

Thanks for the advice - that seems to be consensus that I need to just go off and do this.....

Click to expand...

Richard Boutwell's software makes it as easy as possible. Another tip: Instead of investing in an expensive densitometer or colorimeter, there is a $60 tool called a Color Muse that is sold at hardware stores and online to people trying to match paint colors. Clay Harmon has instructions for using the Color Muse on his website, and even provides a step chart created specifically for it, and a web app for collecting the device's readings for use in Boutwell's software. Easy and inexpensive.

That's right. In addition to the Color Muse, if you already have a flatbed scanner, that will work for monochrome purposes as well.

Personally, I always had problems when trying to use a flatbed scanner for digital negative calibration. I probably didn't fully understand how to get "good numbers" and, eventually, switched to using my ColorMunki to obtain real L*A*B values. It was dicey getting this data into Richard's early Excel-based program, but it got much easier with the later native program. However you decide to work you want to be confident of the numbers.

Alan9940 said:

Personally, I always had problems when trying to use a flatbed scanner for digital negative calibration. I probably didn't fully understand how to get "good numbers" and, eventually, switched to using my ColorMunki to obtain real L*A*B values. It was dicey getting this data into Richard's early Excel-based program, but it got much easier with the later native program. However you decide to work you want to be confident of the numbers.

Click to expand...

Speaking of ColorMunki, so do you have a way of exporting the L*ab data automatically to Excel.

:Niranjan

Alan9940 said:

using my ColorMunki to obtain real L*A*B values

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Is this still supported in present versions of the ColorMunki software? This comment here by Calvin Grier raises some doubts: https://groups.io/g/carbon/message/13799

koraks said:

Is this still supported in present versions of the ColorMunki software? This comment here by Calvin Grier raises some doubts: https://groups.io/g/carbon/message/13799

Click to expand...

If you use the software that came with the ColorMunki Photo, yes. If you try to use their "new and improved" i1Studio software - no. It can do both a single patch in the Spot mode as well as scan a bunch of patches at a time.

:Niranjan.

Thanks, that's useful to know!

nmp said:

Speaking of ColorMunki, so do you have a way of exporting the L*ab data automatically to Excel.

:Niranjan

Click to expand...

Yes...sort of. I haven't used the Excel-based version of QCDN for quite awhile, so please bear with me as I'm churning the 'ole gray matter. I got a separate tool from Richard (not included with the original package) that stripped the luminance values for each patch out of an exported file from the ColorMunki software. Then, it was simply a matter of cut-n-paste to get those values into QCDN. The process was all terribly confusing when I first started, but, once you did it a few times, it got pretty straightforward. One major reason for my initial confusion was that QCDN was advertised as working with ColorMunki "out of the box" and...to put it mildly, NOT! That said, Richard was a tremendous help and after many email exchanges I got everything I needed to make it work.

Not too much later, I moved on to the Mac native version, still utilizing the ColorMunki, and that worked out much better for me. As a matter of fact, I just got a new Epson P700 printer so one day soon I'm going to have to fire up QCDN and build some profiles for this printer.

koraks said:

Is this still supported in present versions of the ColorMunki software? This comment here by Calvin Grier raises some doubts: https://groups.io/g/carbon/message/13799

Click to expand...

I see that Narinjan already answered you.

Yes, nevertheless thank you Alan!

Alan9940 said:

Yes...sort of. I haven't used the Excel-based version of QCDN for quite awhile, so please bear with me as I'm churning the 'ole gray matter. I got a separate tool from Richard (not included with the original package) that stripped the luminance values for each patch out of an exported file from the ColorMunki software. Then, it was simply a matter of cut-n-paste to get those values into QCDN. The process was all terribly confusing when I first started, but, once you did it a few times, it got pretty straightforward. One major reason for my initial confusion was that QCDN was advertised as working with ColorMunki "out of the box" and...to put it mildly, NOT! That said, Richard was a tremendous help and after many email exchanges I got everything I needed to make it work.

Not too much later, I moved on to the Mac native version, still utilizing the ColorMunki, and that worked out much better for me. As a matter of fact, I just got a new Epson P700 printer so one day soon I'm going to have to fire up QCDN and build some profiles for this printer.

Click to expand...

Thanks Alan.

Yeah, on Macs apparently the export to Excel is straightforward as explained by Keith Cooper here. No such luck with PC. I end up just reading the values from each patch and manually enter them in a spread sheet.

:Niranjan.